wheat cakes, crackers, and other food materials made principally from
flour, have practically the same food value as bread. It makes but
little difference in what way flour is prepared as food, for in its
various forms it has practically the same digestibility and nutritive
value.

194. Toast.--When bread is toasted there is no change in the
percentage of total nutrients on a dry matter basis. The change is in
solubility and form, and not in amount of nutrients available. Some of
the starch becomes dextrine, which is more soluble and digestible.[5]
Proteids, on the other hand, are rendered less soluble, which appears to
slightly lower the digestion coefficient. They are somewhat more readily
but not quite so completely digested as those of bread. Digestion
experiments show that toast more readily yields to the diastase and
other ferments than does wheat bread. Toasting brings about ease of
digestion rather than increased completeness of the process. Toast is a
sterile food, while bread often contains various ferments which have not
been destroyed by baking. These undergo incubation during the process of
digestion, particularly in the case of individuals with diseases of the
digestive tract. With normal digestion, however, these ferment bodies do
not develop to any appreciable extent, as the digestive tract disinfects
itself. When the flour is prepared from well cleaned wheat and the
ferment substances which are present mainly in the bran particles have
been removed, a flour of higher sanitary value is secured.

CHAPTER XII

BAKING POWDERS

195. General Composition.--All baking powders contain at least two
materials; one of these has combined carbon dioxid in its composition,
the other some acid constituent which serves to liberate the gas. The
material from which the gas is obtained is almost invariably sodium
bicarbonate, NaHCO_{3}, commonly known as "soda" or "saleratus."
Ammonium carbonate has been used to some extent, but is very seldom used
at the present time. The acid constituent may be one of several
materials, the most common being cream of tartar, tartaric acid, calcium
phosphate, or alum. These may be used separately or in combination. The
various baking powders are designated according to the acid constituent,
as "cream of tartar," "phosphate," and "alum" powders. All of them
liberate carbon dioxid gas, but the products left in the food differ
widely in nature and amount[69].

Baking powder is a chemical preparation which, when brought in contact
with water, liberates carbon dioxid gas. The baking powder is mixed dry
with flour, and when this is moistened the carbon dioxid that is
liberated expands the dough. The action is similar to that of yeast
except that in the case of yeast the gas is given off much more slowly
and no residue is left in the bread. When baking powder is used, there
is a residue left in the food which varies with the material in the
powder. It is the nature and amount of this residue that is important
and makes one baking powder more desirable than another.

[Illustration: FIG. 51.--INGREDIENTS OF A BAKING POWDER.

1, baking powder; 2, cream of tartar; 3, baking soda; 4, starch.]

196. Cream of Tartar Powders.--The acid ingredient of the cream of
tartar powders is tartaric acid, H_{2}C_{4}H_{4}O_{6}. Cream of tartar
is potassium acid tartrate, KHC_{4}H_{4}O_{6}; it contains one atom of
replaceable hydrogen, which imparts the acid properties, and it is
prepared from crude argol, a deposit of grape juice when wine is made.
The residue from this powder is sodium potassium tartrate,
NaKC_{4}H_{4}O_{6}, commonly known as Rochelle salt. This is the active
ingredient of Seidlitz powders and has a purgative effect when taken
into the body. The dose as a purgative is from one half to one ounce. A
loaf of bread as ordinarily made with cream of tartar powder contains
about 160 grains of Rochelle salt, which is 45 grains more than is found
in a Seidlitz powder, but the amount actually eaten at any one time is
small and its physiological effect can probably be disregarded. When a
cream of tartar baking powder is used, the reaction takes place
according to the following equation:

          188            84             210              44       18
  HKH_{4}C_{4}O_{6} + NaHCO_{3} = KNaC_{4}H_{4}O_{6} + CO_{2} + H_{2}O.

The crystallized Rochelle salt contains four molecules of water, so
that, even allowing for some starch filler, there is very nearly as much
weight of material (Rochelle salt) left in the food as there was of the
original powder. If free tartaric acid were used instead of potassium
acid tartrate, the reaction would be as follows:

          150              168              230                           88
  H_{2}C_{4}H_{4}O{6} + 2NaHCO_{3} = Na_{2}C_{2}H_{4}O_{6}.2 H_{2}O + 2CO_{2}.

But the residue, sodium tartrate, is less in proportion. It has
physiological properties very similar to Rochelle salt. Tartaric acid is
seldom used alone, but very often in combination with cream of tartar.
It is more expensive than cream of tartar; but not so much is required,
and it is more rapid in action.

197. Phosphate Baking Powders.--Here the acid ingredient is phosphoric
acid and the compound usually employed is mono-calcium phosphate,
CaH_{4}(PO-{4})_{2}. This is made by the action of sulphuric acid on
ground bone (Ca_{3}(PO_{4})_{2} + 2 H_{2}SO_{4} = CaH_{4}(PO_{4})_{2} +
2 CaSO_{4}), and it is difficult to free it from the calcium phosphate
formed at the same time; hence such powders contain more or less of this
inert material. The reaction which occurs with a phosphate powder is as
follows:

       234                 168           136
  CaH_{4}(PO_{4})_{2} + 2 NaHCO_{3} = CaHPO_{4}

           88         36           142
      + 2 CO_{2} + 2 H_{2}O + Na_{2}HPO_{4}.

Sodium phosphate, according to the United States Dispensatory, is
"mildly purgative in doses of from 1 to 2 ounces." The claim is made by
the makers of phosphate baking powders that the phosphates of sodium and
calcium, products left after the baking, restore the phosphates which
have been lost from the flour in the bran. This baking powder residue
does not restore the phosphates in the same form in which they are
present in grains and it does furnish them in larger amounts--nearly
tenfold. However, the residue from these powders is probably less
objectionable than that from alum powders. The chief drawback to the
phosphate powders is their poor keeping qualities.

198. Alum Baking Powders.--Sulphuric acid is the acid constituent of
these powders. The alums are double sulphates of aluminium and an
alkali metal, and have the general formula _x_Al(SO_{4})_{2} in which
_x_ may be K, Na, or NH_{4}, producing respectively a potash, soda, or
ammonia alum. Potash alum is most commonly used, soda and ammonia alums
to a less extent. The reaction takes place as follows:

           475                 504             157
  2 NH_{4}Al(SO_{4})_{2} + 6 NaHCO_{3} = Al_{2}(OH)_{6}

              426                132            264
      + 3 Na_{2}SO_{4} + (NH_{4})_{2}SO_{4} + 6 CO_{2}.

If it is a potash or soda alum, simply substitute K or Na for NH_{4}
throughout the equation. The best authorities regard alum baking powders
as the most objectionable. Ammonia alum is without doubt the worst form,
since all of the ammonium compounds have an extremely irritating effect
on animal tissue. Sulphates of sodium and potassium are also
objectionable. Aluminium hydroxide is soluble in the slightly acid
gastric juice and has an astringent action on animal tissue, hindering
digestion in a way similar to the alum itself. Many of the alum powders
contain also mono-calcium phosphate; the reaction is as follows:

           475                   234                   336
  2 NH_{4}Al(SO_{4})_{2} + CaH_{4}(PO_{4})_{2} + 4 NaHCO_{3}

          245              136              132
  = Al_{2}(PO_{4})_{2} + CaSO_{4} + (NH_{4})_{2}SO_{4}

           284         176          72
  + 2 Na_{2}SO_{4} + 4 CO_{2} + 4 H_{2}O.

These are probably less injurious than the straight alum powders,
although the residues are, in general, open to the same objection.

199. Inspection of Baking Powders.--Many of the states have enacted
laws seeking to regulate the sale of alum baking powders. Some of these
laws simply require the packages to bear a label setting forth the fact
that alum is one of the ingredients; others require the baking powder
packages to bear a label naming all the ingredients of the powder.

200. Fillers.--All baking powders contain a filler of starch. This is
necessary to keep the materials from acting before the powder is used.
The amount of filler varies from 15 to 50 per cent; the least is found
in the tartrate powders and the most in the phosphate powders. The
amount of gas which a powder gives off regulates its value; it should
give off at least 1/8 of its weight.

201. Home-made Baking Powders.--Baking powders can be made at home for
about one half what they usually cost and they will give equal
satisfaction. The following will make a long-keeping powder: cream of
tartar, 8 ounces; baking soda, 4 ounces; corn starch, 3 ounces. For a
quick-acting powder use but one ounce of starch. The materials should be
thoroughly dry. Mix the soda and starch first by shaking well in a glass
or tin can. Add the cream of tartar last and shake again. Thorough
mixing is essential to good results. Cream of tartar is often
adulterated, but it can be obtained pure from a reliable druggist. To
insure baking powders remaining perfectly dry, they should always be
kept in glass or tin cans, never in paper.

CHAPTER XIII

VINEGAR, SPICES, AND CONDIMENTS

202. Vinegar.--Vinegar is a dilute solution of acetic acid produced by
fermentation, and contains, in addition to acetic acid, small amounts of
other materials in solution, as mineral matter and malic acid, according
to the material from which the vinegar was made. Unless otherwise
designated, vinegar in this country is generally considered to be made
from apples. Other substances, however, are used, as vinegar can be
manufactured from a variety of fermentable materials, as molasses,
glucose, malt, wine, and alcoholic beverages in general. The chemical
changes which take place in the production of vinegars are: (1)
inversion of the sugar, (2) conversion of the invert sugars into
alcohol, and (3) change of alcohol into acetic acid. All these chemical
changes are the result of ferment action. The various invert ferments
change the sugar into dextrose and glucose sugars; then the alcoholic
ferment produces alcohol and carbon dioxid from the invert sugars, and
finally the acetic acid ferment completes the work by converting the
alcohol into acetic acid. The chemical changes which take place in these
different steps are:

            sucrose                   dextrose             levulose
  (1) C_{12}H_{22}O_{11} + H_{2}O = C_{6}H_{12}O_{6} + C_{6}H_{12}O_{6};

        dextrose              alcohol
  (2) C_{6}H_{12}O_{6} = 2 C_{2}H_{5}OH + 2 CO_{2};

         alcohol               acid
  (3) C_{2}H_{5}OH + 2 O = HC_{2}H_{3}O_{2} + H_{2}O.

[Illustration: FIG. 52.--ACETIC ACID FERMENTS. (After KÖNIG.)]

The acetic acid organism, _Mycoderma aceti_, can work only in the
presence of oxygen. It is one of the aerobic ferments, and is present in
what is known as the "mother" of vinegar and is secreted by it. When
vinegar is made in quantity, the process is hastened by allowing the
alcoholic solution to pass through a narrow tank rilled with shavings
containing some of the ferment material, and at the same time air is
admitted so as to secure a good supply of oxygen. When vinegar is made
by allowing cider or wine to stand in a warm place until the
fermentation process is completed, a long time is required--the length
of time depending upon the supply of air and other conditions affecting
fermentation.

In some countries malt vinegar is common. This is produced by allowing a
wort made from malt and barley to undergo acetic acid fermentation,
without first distilling the alcohol as is done in the preparation of
spirit vinegar. In various European countries wine vinegar is in general
use and is made by acetification of the juice of grapes. Sometimes
spirit vinegar is made from corn or barley malt. Alcoholic fermentation
takes place, the alcohol is distilled so that a weak solution remains,
which is acetified in the ordinary way. Such a vinegar can be produced
very cheaply and is much inferior in flavor to genuine wine or cider
vinegar.

Vinegar, when properly made, should remain clear, and should not form a
heavy deposit or produce any large amount of the fungous growth,
commonly called the "mother" of vinegar. In order to prevent the vinegar
from becoming cloudy and forming deposits, it should be strained and
stored in clean jugs and protected from the air. So long as air is
excluded further acetic acid fermentation and production of "mother" of
vinegar cannot take place. When the vinegar is properly made and the
fermentation process has been completed, the acid already produced
prevents all further development of acetic acid ferments. When vinegar
becomes cloudy and produces deposits, it is an indication that the
acetic fermentation has not been completed.

The national standard for pure apple cider vinegar calls for not less
than 4 grams acetic acid, 1.6 grams of apple solids, and 0.25 grams of
apple ash per 100 cubic centimeters, along with other characteristics,
as acidity, sugar, and phosphoric acid content. Many states have special
laws regarding the sale of vinegar.

203. Adulteration of Vinegar.--Vinegar is frequently adulterated by
the addition of water, or by coloring spirit vinegar, thus causing it to
resemble cider vinegar. Formerly vinegar was occasionally adulterated by
the use of mineral acids, as hydrochloric or sulphuric, but since acetic
acid can be produced so cheaply, this form of adulteration has almost
entirely disappeared. Colored spirit vinegar contains merely a trace of
solid matter and can be readily distinguished from cider vinegar by
evaporating a small weighed quantity to dryness and determining the
weight of the solids. Occasionally, however, glucose and other materials
are added so as to give some solids to the spirit vinegar, but such a
vinegar contains only a trace of ash[18]. Attempts have also been made
to carry the adulteration still further by adding lime and soda to give
the colored spirit vinegar the necessary amount of ash. Malt, white
wine, glucose, and molasses vinegars when properly manufactured and
unadulterated are not objectionable, but too frequently they are made to
resemble and sell as cider vinegar. This is a fraud which affects the
pocketbook rather than the health. For home use apple cider vinegar is
highly desirable. There is no food material or food adjunct, unless
possibly ground coffee and spices, so extensively adulterated as
vinegar.

Vinegar has no food value whatever, and is valuable only for giving
flavor and palatability to other foods, and to some extent for the
preservation of foods. It is useful in the household in other ways, as
it furnishes a dilute acid solution of aid in some cooking and baking
operations for liberating gas from soda, and also when a dilute acid
solution is required for various cleaning purposes.

Vinegar should never be kept in tin pails, or any metallic vessel,
because the acetic acid readily dissolves copper, tin, iron, and the
ordinary metals, producing poisonous solutions. Earthenware jugs,
porcelain dishes, glassware, or wooden casks are all serviceable for
storing vinegar.

204. Characteristics of Spices.[70]--Spices are aromatic vegetable
substances characterized as a class by containing some essential or
volatile oil which gives taste and individuality to the material. They
are used for the flavoring of food and are composed of mineral matter
and the various nitrogenous and non-nitrogenous compounds found in all
plant bodies. Since only a comparatively small amount of a spice is used
for flavoring purposes, no appreciable nutrients are added to the food.
Some of the spices have characteristic medicinal properties.
Occasionally they are used to such an extent as to mask the natural
flavors of foods, and to conceal poor cooking and preparation or poor
quality. For the microscopic study of spices the student is referred to
Winton, "Microscopy of Vegetable Foods," and Leach, "Food Inspection and
Analysis."

205. Pepper.--Black and white pepper are the fruit of the pepper plant
(_Piper nigrum_), a climbing perennial shrub which grows in the East and
West Indies, the greatest production being in Sumatra. For the black
pepper, the berry is picked before thoroughly ripe; for the white
pepper, it is allowed to mature. White pepper has the black pericarp or
hull removed. Pepper owes its properties to an alkaloid, piperine, and
to a volatile oil. In the black pepper berries there is present ash to
the extent of about 4.5 per cent, it ought not to be above 6.5 per cent;
ether extract, including piperine and resin, not less than 6.5 per cent;
crude fiber not more than 16 per cent; also some starch and nitrogenous
material. The white pepper contains less ash and cellulose than the
black pepper. Ground pepper is frequently grossly adulterated; common
adulterants being: cracker crumbs, roasted nut shells and fruit stones,
charcoal, corn meal, pepper hulls, mustard hulls, and buckwheat
middlings. The pepper berries wrinkle in drying, and this makes it
difficult to remove the sand which may have adhered to them. An
excessive amount of sand in the ash should be classed as adulteration.
Adulterants in pepper are detected mainly by the use of the microscope.
The United States standard for pepper is: not more than 7 per cent total
ash, 15 per cent fiber, and not less than 25 per cent starch and 6 per
cent non-volatile ether extract.[71]

206. Cayenne.--Cayenne or red pepper is the fruit pod of a plant,
_capsicum_, of which there are several varieties,--the small-fruited
kind, used to make cayenne or red pepper; and the tabasco sort, forming
the basis of tabasco sauce. It is grown mainly in the tropics, and was
used there as a condiment before the landing of Columbus, who took
specimens back to Europe. Cayenne pepper contains 25 per cent of oil,
about 7 per cent of ash, and a liberal amount of starch. The adulterants
are usually of a starchy nature, as rice or corn meal, and the product
is often colored with some red dye.

207. Mustard.--Mustard is the seed of the mustard plant, and is most
often found in commerce in the ground form. The black or brown mustard
has a very small seed and the most aroma. White mustard is much larger
and is frequently used unground. For the ground mustard, only the
interior of the seed is used, the husk being removed in the bolting.
Mustard contains a large amount of oil, part of which is usually
expressed before grinding, and this is the form in which spice grinders
buy it. In mustard flour there is: ash from 4 to 6 per cent, volatile
oil from 0.5 to 2 per cent, fixed oil from 15 to 25 per cent, crude
fiber from 2 to 5 per cent, albuminoids from 35 to 45 per cent, and a
little starch. The principal adulterants are wheat, corn, and rice
flour. When these are used, the product is frequently colored with
turmeric, a harmless vegetable coloring material.

208. Ginger.--Ginger is the rhizome or root of a reed-like plant
(_Zingiber officinale_), native in tropical Asia, chiefly India. It is
cultivated in nearly all tropical countries. When unground it usually
occurs in two forms: dried with the epidermis, or with the epidermis
removed, when it is called scraped ginger. Very frequently a coating of
chalk is given, as a protection against the drug store beetle. Jamaica
ginger is the best and most expensive. Cochin, scraped, African, and
Calcutta ginger range in price in the order given. Ginger contains from
3.6 to 7.5 per cent of ash, from 1.5 to 3 per cent of volatile oil, and
from 3 to 5.5 per cent of fixed oil. There is a large amount of starch.
The chief adulterants are rice, wheat, and potato starch, mustard hulls,
exhausted ginger from ginger-ale and extract factories, sawdust and
ground peanut-shells, and turmeric is frequently used for coloring the
product. The United States standard for ginger is not more than 42 per
cent starch, 8 per cent fiber, and 6 per cent total ash.[71]

209. Cinnamon and Cassia.--The bark of several species of plants
growing in tropical countries furnishes these spices. True cinnamon is a
native of Ceylon, while the cassias are from Bengal and China. In this
country there is more cassia used than cinnamon--cinnamon being rarely
found except in drug stores. Cassia bark is much thicker than cinnamon
bark. The ground spice contains about 1.5 per cent volatile oil and the
same amount of fixed oil, 4 per cent of ash, and some fiber, nitrogenous
matter, and starch. Cereals, cedar sawdust, ground nutshells, oil meal,
and cracker crumbs are the chief adulterants.

210. Cloves.--Cloves are the flower buds of an evergreen tree that
grows in the tropics. These are picked by hand and dried in the sun. In
the order of value, Penang, Sumatra, Amboyna, and Zanzibar furnish the
chief varieties. Cloves rarely contain more than 8 per cent ash, or less
than 10 per cent volatile oil and 4 per cent fixed oil, and 16 to 20 per
cent of tannin-yielding bodies. No starch is present. The chief
adulterants of ground cloves are spent cloves, allspice, and ground
nutshells. Clove stems are also sometimes used and may be detected by a
microscopical examination, since they contain many thick-walled cells
and much fibrous tissue.

211. Allspice.--Allspice, or pimento, is the fruit of an evergreen
tree common in the West Indies. It is a small, dry, globular berry,
two-celled, each cell having a single seed. Allspice contains about 2.5
per cent volatile oil, 4 per cent fixed oil, and 4.5 per cent ash.
Because of its cheapness, it is not generally adulterated, cereal
starches being the most common adulterants.

212. Nutmeg.--Nutmeg is the interior kernel of the fruit of a tree
growing in the East Indies. The fruit resembles a small pear. A fleshy
mantle of crimson color, which is mace, envelopes the seed. Nutmeg
contains about 2.2 per cent ash, 2.5 to 5 per cent volatile oil, and 25
to 35 per cent fixed oil. Mace has practically the same composition.
Extensive adulteration is seldom practiced. The white coating on the
surface of the nutmeg is lime, used to prevent sprouting of the germ.

CHAPTER XIV

TEA, COFFEE, CHOCOLATE, AND COCOA

[Illustration: FIG. 53.--TEA LEAF. (After
WINTON.)]

213. Tea is the prepared leaf of an evergreen shrub or small tree
cultivated chiefly in China and Japan. There are two varieties of
plants. The Assamese, which requires a very moist, hot climate, yields
in India and Ceylon about 400 pounds per acre, and may produce as high
as 1000 pounds. From this plant a number of flushes or pickings are
secured in a year. The Chinese plant grows in cooler climates and has a
smaller, tougher, and darker leaf, which is more delicate than that of
the Assamese and is usually made into green tea. The Chinese tea plant
yields only four or five flushes a year. About 40 per cent of the tea
used in this country comes from Japan and 50 per cent from China. The
tea industry of India and Ceylon has developed rapidly in late years,
and is now second only to that of China. Tea has been raised upon a
small scale in the United States. The quality or grade of the tea
depends upon the leaves used and the method of curing.

214. Composition of Tea.--Black and green teas are produced from the
same species of plant, but owe their difference in color as well as
flavor and odor to methods of preparation. The same plant may yield
several grades of both green and black tea. To produce black tea, the
leaves are bruised to liberate the juices, allowed to ferment a short
time, which develops the color, and then dried.[73] For green tea the
fresh leaves are roasted or steamed, then rolled and dried as quickly as
possible to prevent fermentation. The smaller leaves and the first
picking produce the finest quality of tea. The characteristic flavor and
odor of tea are imparted by a volatile oil, although the odor is
sometimes altered by the tea being brought in contact with orange
flowers, jessamine, or the fragrant olive. There are also present in tea
an alkaloid, theine, which gives the peculiar physiological properties,
and tannin, upon which depends largely the strength of the tea infusion.
The composition of tea is as follows:

  ===========================================
                    |ORIGINAL| GREEN | BLACK
                    |  TEA   |  TEA  |  TEA
  -------------------------------------------
  Tannin, per cent  |  12.91 | 10.64 |  4.89
  Theine, per cent  |   3.30 |  3.20 |  3.30
  Ash, per cent     |   4.97 |  4.92 |  4.93
  Fiber, per cent   |  10.44 | 10.06 | 10.07
  Protein, per cent |  37.33 | 37.43 | 38.90
    (all insoluble) |        |       |
  ===========================================

It will be noticed that green tea contains twice as much tannin as black
tea; during the fermentation which the black tea undergoes, some of the
tannin is decomposed. There is a large amount of protein in tea, but it
is of no food value, because of its insolubility. About half of the ash
is soluble. The tannin is readily soluble, and for this reason green tea
especially should be infused for a very short time and never boiled.
Tannin in foods in large amounts may interfere with the normal digestion
of the protein compounds, because it coagulates the albumin and peptones
after they have become soluble, and thus makes additional work for the
digestive organs.

215. Judging Teas.--Teas are judged according to: (1) the tea as it
appears prepared for market, (2) the infusion, and (3) the out-turn
after infusion. The color should be uniform; if a black tea, it should
be grayish black, not a dead black. The leaves should be uniform in size
or grade. The quality and grade are dependent upon flavor, and, with the
strength of the infusion, are determined by tasting. This work is
rapidly done by the trained tea taster. The out-turn should be of one
color; no bright green leaves should be present; evenness of make is
judged by the out-turn. The flavor of a tea is largely a matter of
personal judgment, but from a physiological point of view black teas are
given the preference.

216. Adulteration of Tea.--A few years ago tea was quite extensively
adulterated, but the strict regulation of the government regarding
imported tea has greatly lessened adulteration. The most common form
was the use of spent leaves, _i.e._ leaves which had been infused.
Leaves of the willow and other plants which resemble tea were also used,
as well as large quantities of tea stems. Facing or coloring is also an
adulteration, since it is done to give poor or damaged tea a brighter
appearance. "Facing consists in treating leaves damaged in manufacture
or which from age are inferior, with a mixture containing Prussian blue,
turmeric, indigo, or plumbago to impart color or gloss, and with a
fraudulent intent. There is no evidence that the facing agents are
deleterious to health in the small quantities used, but as they are used
for purposes of deception, they should be discouraged."[73] Facing and
the addition of stems are the chief adulterations practiced at present.

217. Food Value and Physiological Properties of Tea.--Tea infusion
does not contain sufficient nutrients to entitle it to be classed as a
food. It is with some persons a stimulant. The caffein or theine in tea
is an alkaloid that has characteristic physiological properties. In
doses of from three to five grains, according to the United States
Dispensatory, "it produces peculiar wakefulness." Larger doses produce
intense physical restlessness, mental anxiety, and obstinate
sleeplessness. "It has no effect upon the motor nerves, but is believed
to have a visible effect upon the sensatory nerves." (United States
Dispensatory.) Experiments with animals show that it causes elevation
of the arterial pressure. It is used as a cardiac stimulant. The
quantity of theine consumed in a cup of tea is about 4/5 of a grain, or
1/4 of a medicinal dose.

[Illustration: FIG. 54.--COFFEE BERRIES.

1, Mocha; 2, Java; 3, Rio.]

218. Composition of Coffee.--The coffee tree is an evergreen
cultivated in the tropics. It grows to a height of 30 feet, but when
cultivated is kept pruned to from 6 to 10 feet. The fruit, which
resembles a small cherry, with two seeds or coffee grains embedded in
the pulp, is dried and the seeds removed, cleaned, and graded. Coffee
has an entirely different composition from tea; it is characterized by
a high per cent of fat and soluble carbohydrates, and also contains an
essential oil and caffein, an alkaloid identical with theine. Tannic
acid, not as free acid, is combined with caffein as a tannate.

  ======================================
              |RAW COFFEE|ROASTED COFFEE
  --------------------------------------
              | Per Cent | Per Cent
  Water       |  11.23   |   1.15
  Ash         |   3.92   |   4.75
  Fat         |  12.27   |  14.48
  Sugar, etc. |   0.66   |   8.55
  Protein     |  12.07   |  13.98
  Caffein     |   1.21   |   1.24
  ======================================

The high per cent of sugar and other soluble carbohydrates in roasted
coffee is caused by the action of heat upon the non-nitrogenous
compounds. Coffee cannot be considered a food, because only a
comparatively small amount of the nutrients are soluble and available.
It is a mildly stimulating beverage. With some individuals it appears to
promote the digestive process, while with others its effect is not
beneficial. Coffee is more extensively used in this country than tea,
and is subject to greater adulteration. It is adulterated by facing and
glazing; _i.e._ coloring the berries to resemble different grades and
coating them with caramel and dextrine. Spent coffee grains and coffee
that has been extracted without grinding are also used as adulterants.
Imitation berries made of rye, corn, or wheat paste, molded, colored
with caramel, and baked have been found mixed with genuine coffee
berries. Roasted cereals and chicory are used extensively to adulterate
ground coffee. Chicory is prepared from the root of the chicory plant,
which belongs to the same family as the dandelion. It is claimed by some
that a small amount of chicory improves the flavor of coffee. However,
when chicory is added to coffee, it should be so stated on the label and
the amount used given. The dextrine and sugar used in glazing are
browned or caramelized during roasting and impart a darker color to the
infusion, making it appear better than it really is. The glazing also
makes the coffee retain moisture which would otherwise be driven off
during roasting. Coffee contains such a large per cent of oil that the
berries generally float when thrown on water, while the imitation
berries sink. Chicory also sinks rapidly and colors the water brown,
while the coffee remains floating for some time.

There are three kinds of coffee in general use: Java, Mocha, and Rio or
Brazil. The Brazil coffee has the largest berry and is usually styled by
dealers as "low" or "low middlings." The Java coffee berries are smaller
and paler in color, the better grades being brown. Mocha usually
commands the highest price in commerce. The seeds are small and dark
yellow before roasting.

219. Cereal Coffee Substitutes.

     "A few of these preparations contain a little true coffee, but for
     the most part they appear to be made of parched grains of barley,
     wheat, etc., or of grain mixed with pea hulls, ground corncobs, or
     wheat middlings. It is said that barley or wheat parched, with a
     little molasses, in an ordinary oven, makes something
     indistinguishable in flavor from some of the cereal coffees on the
     market. If no coffee is used in the cereal preparations, the claim
     that they are not stimulating is probably true. As for the
     nutritive value, parching the cereals undoubtedly renders some of
     the carbohydrates soluble, and a part of this soluble matter passes
     into the decoction, but the nutritive value of the infusion is
     hardly worth considering in the dietary."[56]

220. Cocoa and Chocolate Preparations.--Cocoa and chocolate are
manufactured from the "cocoa bean," the seed of a tree native to
tropical America. The beans are inclosed in a lemon-yellow, fleshy pod.
They are removed from the pulp, allowed to undergo fermentation, and
dried by exposure to the air and light, which hardens them and gives
them a red color. This method produces what is known as the "fermented
cocoa." For the "unfermented cocoa," the beans are dried without
undergoing fermentation. Fermentation removes much of the acidity and
bitterness characteristic to the unfermented bean, and when properly
regulated develops flavor. The original bean contains about 50 per cent
fat, part of which is removed in preparing the cocoa. This fat is sold
as cocoa butter. In the preparation of some brands of cocoa, alkalies,
such as soda and potash, are used to form a combination with the fat to
prevent its separating in oily globules. This treatment improves the
appearance of the cocoa, but experiments show the albumin to be somewhat
less digestible and the soap-like product resulting not as valuable a
food as the fat. Such preparations have a high per cent of ash. There
is no objection from a nutritive point of view to a cocoa in which the
fat separates in oily globules.

221. Composition of Cocoa.--The cocoa bean, when dried or roasted and
freed from its husk and ground, is sold as cracked cocoa, or cocoa nibs.
From cocoa nibs the various cocoa and chocolate preparations are made.
Cocoas vary in composition according to the extent to which the fat is
removed during the process of manufacture and the nature and extent to
which other ingredients are added. An average cocoa contains about 20
per cent of proteids, and 30 per cent fat, also starch, sugar, gums,
fiber, and ash, as well as theobromine, a material very similar to
theine and caffein in tea and coffee, but not such an active stimulant.
Cocoa is not easily soluble, but it may be ground so fine that a long
time is required for its sedimentation; or sugar or other soluble
material may be added during the process of manufacture to increase the
specific gravity of the liquid to such an extent that the same object is
attained without such fine grinding. The first method is to be
preferred. Cocoa and its preparations are richer in nutritive substances
than tea and coffee and have this added advantage that both the soluble
and insoluble portions become a part of the beverage. Owing to the small
amount used for a cup of cocoa, independent of the milk it does not add
much in the way of nutrients to the ration.

222. Chocolate.--Plain chocolate is prepared from cocoa nibs without
"removal of the fat or other constituents except the germ." It differs
in chemical composition from cocoa by containing more fat and less
protein; it has nearly the same chemical composition as the cocoa nibs.
It is officially defined as containing "not more than 3 per cent of ash
insoluble in water, 3-1/2 per cent of crude fiber and 9 per cent of
starch, and less than 45 per cent cocoa fat."[71]

By the addition of sugar, sweet chocolates are made. They vary widely in
composition according to the flavors and amounts of sugar added during
their preparation. The average composition of cocoa nibs, standard
cocoa, and plain chocolate is as follows:

  ==============================================================
                  |  COCOA |  COMPOSITION OF  | COMPOSITION OF
                  |   NIBS |  STANDARD COCOA  |  PLAIN CHOCOLATE
                  |---------------------------------------------
                  |Per Cent|     Per Cent     |   Per Cent
  Water           |  3.00  |        --        |     3.09
  Ash             |  3.50  |       4.20       |     3.08
  Theobromine     |  1.00  |        --        |      --
  Caffein         |  0.50  |        --        |      --
  Crude Protein   | 12.00  |        --        |      --
  Crude fiber     |  2.50  |       5.02       |     2.63
  Fat             | 50.00  |      32.52       |    49.81
  Starch and other|        |                  |
   non-nitrogenous|        |                  |
   matter         | 27.50  |        --        |      --
  ============================================================

223. Adulteration of Chocolate and Cocoa.--The various chocolate and
cocoa preparations offer an enticing field for sophistication; they are
not, however, so extensively adulterated as before the enforcement of
national and state pure food laws. The most common adulterants are
starch, cocoa shells, and occasionally iron dioxid and other pigments to
give color, also foreign fats to replace the fat removed and to give the
required plasticity for molding.

224. Comparative Composition of Beverages.--Tea and coffee as
beverages contain but little in the way of nutrients other than the
cream and sugar used in them. The solid matter in tea and coffee
infusions amounts to less than 1.2 per cent. When cocoa is made with
milk, it is a beverage of high nutritive value due mainly to the milk.

COMPOSITION OF BEVERAGES[56]

  =============================================================================
                          |          |          |          |          | FUEL
      KIND OF BEVERAGE    |  WATER   | PROTEIN  |   FAT    |  CARBO-  | VALUE
                          |          |          |          | HYDRATES | PER LB.
  ------------------------|----------|----------|----------|----------|--------
                          | Per Cent | Per Cent | Per Cent | Per Cent |Calories
  Commercial cereal coffee|          |          |          |          |
    (0.5 ounce to         |          |          |          |          |
      1 pint water)       |   98.2   |    0.2   |    --    |   1.4    |    30
  Parched corn coffee     |          |          |          |          |
    (1.6 ounces to        |          |          |          |          |
       1 pint water)      |   99.5   |    0.2   |    --    |   0.5    |    13
  Oatmeal water (1 ounce  |          |          |          |          |
    to 1 pint water)      |   99.7   |    0.3   |    --    |   0.3    |    11
  Coffee (1 ounce         |          |          |          |          |
    1 pint water)         |   98.9   |    0.2   |    --    |   0.7    |    16
  Tea (0.5 ounce to       |          |          |          |          |
    1 pint water)         |   99.5   |    0.2   |    --    |   0.6    |    15
  Cocoa (0.5 ounce to     |          |          |          |          |
    1 pint milk)          |   84.5   |    3.8   |    4.7   |   6.0    |   365
  Cocoa (0.5 ounce to     |          |          |          |          |
    1 pint water)         |   97.1   |    0.6   |    0.9   |   1.1    |    65
  Skimmed milk            |   90.5   |    3.4   |    0.3   |   5.1    |   170
  =============================================================================

CHAPTER XV

THE DIGESTIBILITY OF FOODS

225. Digestibility, How Determined.--The term "digestibility," as
applied to foods, is used in two ways: (1) meaning the thoroughness of
the process, or the completeness with which the nutrients of the food
are absorbed and used by the body, and (2) meaning the ease or comfort
with which digestion is accomplished. Cheese is popularly termed
indigestible, and rice digestible, when in reality the nutrients of
cheese are more completely although more slowly digested than those of
rice. In this work, unless otherwise stated, digestibility is applied to
the completeness of the digestion process.

The digestibility of a food is ascertained by means of digestion
experiments, in which all of the food consumed for a certain period,
usually two to four days, is weighed and analyzed, and from the weight
and composition is determined the amount, in pounds or grams, of each
nutrient consumed.[72] In like manner the nutrients in the indigestible
portion, or feces, are determined from the weight and composition of the
feces. The indigestible nutrients in the feces are deducted from the
total nutrients of the food, the difference being the amount digested,
or oxidized in the body. When the food is digested, the various
nutrients undergo complete or partial oxidation, with the formation of
carbon dioxid gas, water, urea (CH_{4}N_{2}O), and other compounds. The
feces consist mainly of the compounds which have escaped digestion. The
various groups of compounds of foods do not all have the same
digestibility; for example, the starch of potatoes is 92 per cent
digestible, while the protein is only 72 per cent. The percentage amount
of a nutrient that is digested is called the digestion coefficient.

In the following way the digestibility of a two-days ration of bread and
milk was determined: 773.5 grams of bread and 2000 grams of milk were
consumed by the subject. The dried feces weighed 38.2 grams. The foods
and feces when analyzed were found to have the following
composition:[62]

  =====================================================================
      COMPOSITION    |    BREAD       |      MILK     |     FECES[A]
  ---------------------------------------------------------------------
  Water              |     44.13      |     86.52     |       --
  Crude protein      |      7.75      |      3.15     |      25.88
  Ether extract      |      0.90      |      4.63     |      18.23
  Ash                |      0.32      |      0.70     |      26.35
  Carbohydrates      |     46.90      |      5.00     |      29.54
  Calories per gram  |      2.450     |      0.79     |       5.083
  =====================================================================

[Footnote A: Results on dry-matter basis.]

STATEMENT OF RESULTS OF A DIGESTION EXPERIMENT

  =============================================================================
    FOOD CONSUMED   |  WEIGHT  |  PROTEIN |  ETHER  | CARBO- |       | HEAT OF
                    |    OF    | N × 6.25 | EXTRACT |  HY-   |  ASH  | COMBUS-
                    | MATERIAL |          |         | DRATES |       | TION
  ------------------+----------+----------+---------+--------+-------+---------
                    |   Grams  |   Grams  |   Grams |  Grams | Grams | Calories
  Bread             |    773.5 |    60.0  |     6.9 |  362.8 |   2.5 |  1895
  Milk              |   2000.0 |    63.0  |    92.6 |  100.0 |  14.0 |  1585
                    |          |  ------- + ------- + -------+-------+---------
        Total       |     38.2 |   123.0  |    99.5 |  462.8 |  16.5 |  3480
  Feces             |          |     9.9  |     7.0 |   11.3 |  10.1 |   194
                    |          |  ------- + ------- + -------+-------+---------
  Total amount      |          |   113.1  |    92.5 |  451.5 |   6.4 |  3286
    digested        |          |          |         |        |       |
  Per cent digested |          |          |         |        |       |
    or coefficients |          |          |         |        |       |
    of digestibility|          |    92.0  |    93.0 |  97.5  |  38.8 |  94.4
                    |          |          |         |        |       |
  Available energy  |          |     --   |     --  |   --   |   --  |  90.0
  =============================================================================

In this experiment 92 per cent of the crude protein, 93 per cent of the
ether extract, and 97.5 per cent of the carbohydrates of the bread and
milk ration were digested and absorbed by the body. In calculating the
available energy, correction is made for the unoxidized residue, as urea
and allied forms. It is estimated that for each gram of protein in the
ration there was an indigestible residue yielding 1.25 calories.

226. Available Nutrients.--A food may contain a comparatively large
amount of a compound, and yet, on account of its low digestibility, fail
to supply much of it to the body in an available form. Hence it is that
the value of a food is dependent not alone on its composition, but also
on its digestibility. The digestible or available nutrients of a food
are determined by multiplying the per cent of each nutrient which the
food contains by its digestion coefficient. For example, a sample of
wheat flour contains 12 per cent protein, 88 per cent of which is
digestible, making 10.56 per cent of available or digestible protein (12
× 0.88-10.56). Graham flour made from similar wheat contains 13 per cent
total protein, and only 75 per cent of the protein is digestible, making
9.75 per cent available (13 × 0.75 = 9.75). Thus one food may contain a
larger total but a smaller available amount of a nutrient than another.

227. Available Energy.--The available energy of a food or a ration is
expressed in calories. A ration for a laborer at active out-of-door work
should yield about 3200 calories. The calory is the unit of heat, and
represents the heat required to raise the temperature of a kilogram of
water 1° C., or four pounds of water 1° F. The caloric value of foods is
determined by the calorimeter, an apparatus which measures heat with
great accuracy. A pound of starch, or allied carbohydrates, yields 1860
calories, and a pound of fat 4225 (see Section 13). While a gram of
protein completely burned produces 7.8 calories, digested it yields only
about 4.2 calories, because, as explained in the preceding section, not
all of the carbon and oxygen are oxidized.[59] The caloric value or
available energy of a ration can be calculated from the digestible
nutrients by multiplying the pounds of digestible protein and
carbohydrates by 1860, the digestible fat by 4225, and adding the
results. For determination of the available energy of foods under
different experimental conditions, and where great accuracy is desired,
a specially constructed respiration calorimeter has been devised, which
is built upon the same principle as an ordinary calorimeter, except it
is large enough to admit a person, and is provided with appliances for
measuring and analyzing the intake and outlet of air.[74] The heat
produced by the combustion of the food in the body warms the water
surrounding the calorimeter chamber, and this increase in temperature is
determined by thermometers reading to 0.005 of a degree or less.

[Illustration: FIG. 55.--CALORIMETER.]

228. Normal Digestion and Health.--While the process of digestion has
been extensively studied, it is not perfectly understood. Between the
initial compounds of foods and their final oxidation products a large
number of intermediate substances are formed, and when digestion fails
to take place in a normal way, toxic or poisonous compounds are produced
and various diseases result. It is probable that more diseases are due
to imperfect or malnutrition than to any other cause. There is a very
close relationship between health and normal digestion of the food.

The cells in the different parts of the digestive tract secrete fluids
containing substances known as soluble ferments, or enzymes, which act
upon the various compounds of foods, changing them chemically and
physically so that they can be absorbed and utilized by the body. (See
Section 31.) Some of the more important ferments are: ptyolin of the
saliva, pepsin of the stomach, and pancreatin and diastase of the
intestines. In order that these ferments may carry on their work in a
normal way, the acidity and alkalinity of the different parts of the
digestive tract must be maintained. The gastric juice contains from 0.1
to 0.25 per cent of hydrochloric acid, imparting mildly antiseptic
properties; and while the peptic ferment works in a slightly acid
solution, the tryptic ferment requires an alkaline solution. To secrete
the necessary amount and quality of digestive fluids, the organs must be
in a healthy condition. Many erroneous ideas regarding the digestion of
foods are based upon misinterpretation of facts by persons suffering
from impaired digestion, and attempts are frequently made to apply to
normal digestion generalizations applicable only to diseased conditions.

229. Digestibility of Animal Foods.--The proteids and fats in animal
foods, as meats, are more completely digested than the same class of
nutrients in vegetables. In general, about 95 per cent of the proteids
of meats is digestible, while those in vegetables are often less than 85
percent digestible. The amount of indigestible residue from animal foods
is small; while from vegetables it is large, for the cellulose prevents
complete absorption of the nutrients and, as a result, there is much
indigestible residue. Animal foods are concentrated, in that they
furnish large amounts of nutrients in digestible forms. There is less
difference in the completeness with which various meats are digested
than in their ease of digestion; the proteins all have about the same
digestion coefficients, but vary with individuals as to ease of
digestion and time required. It is generally considered that the
digestible proteins, whether of animal or vegetable origin, are equally
valuable for food purposes. This is an assumption, however, that has not
been well established by experimental evidence. In a mixed ration, the
proteins from different sources appear to have the same nutritive value,
but as each is composed of different radicals and separated into
dissimilar elementary compounds during the process of digestion, they
would not necessarily all have the same food value.

There is but little difference between the fats and proteins of meats as
to completeness of digestion,--the slight difference being in favor of
the proteins. Some physiologists claim that the fat, which in some meats
surrounds the bundles of fiber (protein), forming a protecting coat,
prevents the complete solvent action of the digestive fluid. Very fat
meats are not as completely digested as those moderately fat. It is also
claimed that the digestibility of the meat is influenced by the
mechanical character, as toughness of the fiber.

230. Digestibility of Vegetable Foods.--Vegetable foods vary in
digestibility with their mechanical condition and the amount of
cellulose or fiber. In some the nutrients are so embedded in cellular
tissue as to be protected from the solvent action of the digestive
fluids, and in such cases the digestibility and availability are low.
The starches and sugars are more completely digested than any other of
the nutrients of vegetables; in some instances they are from 95 to 98
per cent digestible. Some cellular tissue, but not an excess, is
desirable in a ration, as it exerts a favorable mechanical action upon
the organs of digestion, encourages peristalsis, and is an absorbent and
dilutant of the waste products formed during digestion. For example, in
the feeding of swine, it has been found that corn and cob meal often
gives better results than corn fed alone. The cob contains but little in
the way of nutrients, but it exerts a favorable mechanical action upon
digestion. Occasionally too many bulky foods are combined, containing
scant amounts of nutrients, so that the body receives insufficient
protein. This is liable to be the case in the dietary of the strict
vegetarian. Many of the vegetables possess special dietetic value, due
to the organic acids and essential oils, as cited in the chapter on
fruits and vegetables. The value of such foods cannot always be
determined from their content of digestible protein, fat, and
carbohydrates. This is particularly evident when they are omitted from
the ration, as in the case of a restricted diet consisting mainly of
animal foods. Many vegetables have low nutritive value on account of
their bulky nature and the large amount of water and cellulose which
they contain, which tends to decrease digestibility and lower the amount
of available nutrients. Because of their bulk and fermentable nature,
resulting in the formation of gases, a diet of coarse vegetables has a
tendency to cause distention and enlargement of the intestinal organs.
The carbohydrates, which are the chief constituents of vegetables, are
digested mainly in the intestines, and require special mechanical
preparation in the stomach, hence the nutrients of vegetables are not,
as a rule, as easily digested as those of animal foods.

231. Factors influencing Digestion.--There are a number of factors
which influence completeness as well as ease of digestion, as: (1)
combination of foods; (2) amount of food; (3) method of preparation; (4)
mechanical condition of the food; (5) palatability; (6) physiological
properties; (7) individuality of the consumer; and (8) psychological
influences.

232. Combination of Foods.--In a mixed ration the nutrients are
generally more completely digested than when only one food is used. For
example, milk is practically all digested when it forms a part of a
ration, and it also promotes digestibility of the foods with which it is
combined, but when used alone it is less digestible.[27] Bread alone and
milk alone are not as completely digested as bread and milk combined.
The same in a general way has been observed in the feeding of farm
animals,--better results are secured from combining two or more foods
than from the use of one alone. The extent to which one food influences
the digestibility of another has not been extensively studied.

In a mixed ration, consisting of several articles of food of different
mechanical structure, the work of digestion is more evenly distributed
among the various organs. A food often requires special preparation on
the part of the stomach before it can be digested in the intestines, and
if this food is consumed in small amounts and combined with others of
different structure, the work of gastric digestion is lessened so that
the foods are properly prepared and normal digestion takes place. The
effect which one food exerts upon the digestibility of another is
largely mechanical.

233. Amount of Food.--Completeness as well as ease of digestion is
influenced by the amount of food consumed. In general, excessive amounts
are not as completely digested as moderate amounts. In digestion
experiments with oatmeal and milk, it was found that when these foods
were consumed in large quantities the fat and protein were not as
completely absorbed by the body as when less was used, the protein being
7 per cent and the fat 6 per cent more digestible in the medium ration.
Experiments with animals show that economical results are not secured
from an excess of food.[5] Some individuals consume too much food, and
with them a restricted diet would be beneficial, while others err in not
consuming enough to meet the requirements of the body. Quite frequently
it is those who need more food who practice dieting. When there is
trouble with digestion, it is not always the amount or kind of food
which is at fault, but other habits may be such as to affect digestion.
The active out-of-door laborer can with impunity consume more food,
because there is greater demand for nutrients, and the food is more
completely oxidized in the body and without the formation of poisonous
waste products. The amount of food consumed should be sufficient to meet
all the demands of the body and maintain a normal weight.

234. Method of Preparation of Food.--The extent to which methods of
cooking and preparation influence completeness of digestion has not been
extensively investigated. As is well known, they have great influence
upon ease and comfort of digestion. During cooking, as discussed in
Chapter II, extensive physical and chemical changes occur, and these in
turn affect digestibility. When the cooking has not been sufficient to
mechanically disintegrate vegetable tissue, the digestive fluids fail to
act favorably upon the food. Cooking is also beneficial because it
renders the food sterile and destroys all objectionable microörganisms
which, if they remain in food, readily undergo incubation in the
digestive tract, interfering with normal digestion. Prolonged heat
causes some foods to become less digestible, as milk, which digestion
experiments show to be more completely digested when fresh than when
sterilized. Pasteurized milk, which is not subjected to so high a
temperature as sterilized milk, is more completely digested. See Chapter
VII for discussion of sterilizing and pasteurizing milk.[38] The
benefits derived from the destruction of the objectionable bacteria in
foods are, however, greater than the losses attendant on lessened
digestibility due to the action of heat. The method of preparation of a
food affects its digestibility mainly through change in mechanical
structure, and modification of the forms in which the nutrients are
present.[5]

235. Mechanical Condition of Foods.--The mechanical condition of foods
as to density and structure of the particles and the extent to which
they are disintegrated in their preparation for the table influences
digestibility to a great extent. The mechanics of digestion is a subject
that has not been extensively investigated, and it is one of great
importance, as biological and chemical changes cannot take place if the
food is not in proper mechanical condition. In general, the finer the
food particles, the more completely the nutrients are acted upon by the
digestive fluids and absorbed by the body. Nevertheless, the diet should
not consist entirely of finely granulated foods. Some foods are valuable
mainly because of the favorable action they exert mechanically upon
digestion, rather than for the nutrients they contain.[62] Coarsely
granulated breakfast foods, whole wheat flour, and many vegetables
contain sufficient cellular tissue to give special value from a
mechanical rather than a chemical point of view. The extent to which
coarsely and finely granulated foods should enter into the ration is a
question largely for the individual to determine. Experiments with pigs
show that if large amounts of coarse, granular foods are consumed, the
tendency is for the digestive tract to become inflamed and less able to
exercise its normal functions. Coarsely granulated foods have a tendency
to pass through the digestive tract in less time than those that are
finely granulated, due largely to increased peristaltic action, and the
result is the food is not retained a sufficient length of time to allow
normal absorption to take place. In the feeding of farm animals, it has
been found that the mechanical condition of the food has a great
influence upon its economic use. Rations that are either too bulky or
too concentrated fail to give the best results. In the human ration, the
mechanical condition of the food is equally as important as its chemical
composition.

236. Mastication is an important part of digestion, and when foods are
not thoroughly masticated, additional work is required of the stomach,
which is usually an overworked organ because of doing the work of the
mouth as well. Although much of the mechanical preparation and mixing of
foods is of necessity done in the stomach, some of it may advantageously
be done in the mouth. The stomach should not be required to perform the
function of the gizzard of a fowl.

237. Palatability of Foods.--Many foods naturally contain essential
oils and other substances which impart palatability. These have but
little in the way of nutritive value, but they assist in rendering the
nutrients with which they are associated more digestible. Palatability
of a food favorably influences the secretion of the gastric and other
digestive fluids, and in this way the natural flavors of well-prepared
foods aid in digestion. In the feeding of farm animals it has been found
that when foods are consumed with a relish better returns are secured
than when unpalatable foods are fed. To secure palatability the
excessive use of condiments is unnecessary. It is possible to a great
extent during preparation to develop and conserve the natural flavors.
Some foods contain bitter principles which are removed during the
cooking, while in others pleasant flavors are developed. Palatability is
an important factor in the digestibility of foods.

238. Physiological Properties of Food.--Some food materials,
particularly fruits and vegetables, contain compounds which have
definite physiological properties, as tannin which is an astringent,
special oils which exert a cathartic action, and the alkaloids which
serve as irritants to nerve centers. Wheat germ oil is laxative, and it
is probable that the physiological properties of graham and whole wheat
breads are due in some degree to the oil which they contain.[67] The
use of fruits, herbs, and vegetables for medicinal purposes is based
upon the presence of compounds possessing well-defined medicinal
properties. As a rule food plants do not contain appreciable amounts of
such substances, and the use of food for medicinal effect should be by
the advice of a physician. The physiological properties of some foods
are due to bacterial products. See Chapter XX.

239. Individuality.--Material difference in digestive power is
noticeable among individuals. Digestion experiments show that one person
may digest 5 per cent more of a nutrient than another. This difference
appears to be due to a number of factors, as activity of the organs, as
affected by exercise and kind of labor performed; abnormal composition
of the digestive fluids; or failure of the different parts of the
digestive tract to act in harmony. Individuality is one of the most
important factors in digestion. Persons become accustomed to certain
foods through long usage, and the digestive tract adapts itself to those
foods, rendering sudden and extreme changes in the dietary hazardous.
Common food articles may fail to properly digest in the case of some
individuals, while with others they are consumed with benefit. What is
food to one may prove to be a poison to another, and while general
statements can be made in regard to the digestibility of foods,
individual differences must be recognized.

240. Psychological Factors.--Previously conceived ideas concerning
foods influence digestibility. Foods must be consumed with a relish in
order to secure the best results, as flow of the digestive fluids and
activity of the organs are to a certain extent dependent upon the nerve
centers. If it is believed that a food is poisonous or injurious, even
when the food is wholesome, normal digestion fails to take place. In
experiments by the author, in which the comparative digestibility of
butter and oleomargarine was being studied, it was found that when the
subjects were told they were eating oleomargarine, its digestibility was
depressed 5 per cent, and when they were not told the nature of the
material, but assumed that butter was oleomargarine, the digestibility
of the butter was lowered about 6 per cent.[13] Preconceived notions in
regard to foods, not founded upon well-established facts, but due to
prejudice resulting from ignorance, cause many valuable foods to be
excluded from the dietary. Many persons, like the foreign lady who,
visiting this country, said she ate only acquaintances, prefer foods
that have a familiar taste and appearance, and any unusual taste or
appearance detracts from the value because of the psychological
influence upon digestion.

CHAPTER XVI

COMPARATIVE COST AND VALUE OF FOODS

241. Cost and Nutrient Content of Foods.--The market price and the
nutritive value of foods are often at variance, as those which cost the
most frequently contain the least nutrients.[75] It is difficult to make
absolute comparisons as to the nutritive value of foods at different
prices, because they differ not only in the amounts, but also in the
kinds of nutrients. While it is not possible to express definitely the
value of one food in terms of another, approximate comparisons may be
made as to the amounts of nutrients that can be secured for a given sum
of money when foods are at different prices, and tables have been
prepared making such comparisons.

[Illustration: FIG. 56.--COMPOSITION OF FOODS.

(From Office of Experiment Stations Bulletin.)]

242. Nutrients Procurable for a Given Sum.[7]--To ascertain the
nutrients procurable for a given sum first determine the amount in
pounds that can be obtained, say, for ten cents, and then multiply by
the percentages of fat, protein, carbohydrates, and calories in the
food. The results are the amounts, in pounds, of nutrients procurable
for that sum of money. For example: if milk is 5 cents per quart, two
quarts or approximately four pounds, can be procured for 10 cents. If
the milk contains fat, 4 per cent, protein, 3.3 per cent, carbohydrates,
5 per cent, and fuel value, 310 calories per pound, multiplying each of
these by 4 gives the nutrients and fuel value in four pounds, or 10
cents worth of milk, as follows:

  Protein             0.13 lb.
  Fat                 0.16 lb.
  Carbohydrates       0.2 lb.
  Calories            1240

If it is desired to compare milk at 5 cents per quart with round steak
at 15 cents per pound, 10 cents will procure 0.66, or two thirds of a
pound of round steak containing on an average (edible portion) 19 per
cent protein, 12.8 per cent fat, and yielding 890 calories per pound. If
10 per cent is refuse, there is edible about 0.6 of a pound. The amounts
of nutrients in the 0.6 of a pound of steak, edible portion, or 0.66 lb.
as purchased would be:

  Protein          0.11 lb.
  Fat              0.08 lb.
  Calories          534

It is to be observed that from the 10 cents' worth of milk a little more
protein, 0.08 of a pound more fat, and nearly two and one half times as
many calories can be secured as from the 10 cents' worth of meat. This
is due to the carbohydrates and the larger amount of fat which the milk
contains. At these prices, milk should be used liberally in the dietary,
as it furnishes more of all the nutrients than does meat. It would not
be advisable to exclude meat entirely from the ration, but milk at 5
cents per quart is cheaper food than meat at 15 cents per pound. In
making comparisons, preference cannot always be given to one food
because of its containing more of any particular nutrient, for often
there are other factors that influence the value.

243. Comparing Foods as to Nutritive Value.--In general, preference
should be given to foods which supply the most protein, provided the
differences between the carbohydrates and fats are not large. When the
protein content of two foods is nearly the same, but the fats and
carbohydrates differ materially, the preference may safely be given to
the food which supplies the larger amount of total nutrients. A pound of
protein in a ration is more valuable than a pound of either fat or
carbohydrates, although it is not possible to establish an absolute
scale as to the comparative value of these nutrients, because they serve
different functional purposes in the body. It is sometimes necessary to
use small amounts of foods rich in protein in order to secure a balanced
ration; excessive use of protein, however, is not economical, as that
which is not needed for functional purposes is converted into heat and
energy which could be supplied as well by the carbohydrates, and they
are less expensive nutrients.

[Illustration: FIG. 57.--PECUNIARY ECONOMY OF FOOD.

(From Office of Experiment Stations Bulletin.)]

TEN CENTS WILL PURCHASE: (From Farmer's Bulletin No. 142, U. S.
Dept. of Agr.)

  =============================================================================
                          |       | TOTAL   |        |       |        |
                          |       | WEIGHT  |        |       |        |
    KIND OF FOOD          | PRICE | OF FOOD |        |       |  CAR-  |
      MATERIAL            |  PER  | MATE-   |PROTEIN |  FAT  |  BOHY- |  ENERGY
                          | POUND | RIAL    |        |       | DRATES |
  ------------------------+-------+---------+--------+-------+---------+-------
                          | Cents | Pounds  | Pound  | Pound | Pounds |Calories
  Beef, sirloin           |   25  |   0.40  |  0.06  |  0.06 |   --   |    410
      Do.                 |   20  |   0.50  |  0.08  |  0.08 |   --   |    515
      Do.                 |   15  |   0.67  |  0.10  |  0.11 |   --   |    685
  Beef, round             |   16  |   0.63  |  0.11  |  0.08 |   --   |    560
      Do.                 |   14  |   0.71  |  0.13  |  0.09 |   --   |    630
      Do.                 |   12  |   0.83  |  0.15  |  0.10 |   --   |    740
  Beef, shoulder clod     |   12  |   0.83  |  0.13  |  0.08 |   --   |    595
      Do.                 |    9  |   1.11  |  0.18  |  0.10 |   --   |    795
  Beef, stew meat         |    5  |   2.00  |  0.29  |  0.23 |   --   |   1530
  Beef, dried, chipped    |   25  |   0.40  |  0.10  |  0.03 |   --   |    315
  Mutton chops, loin      |   16  |   0.63  |  0.08  |  0.17 |   --   |    890
  Mutton, leg             |   20  |   0.50  |  0.07  |  0.07 |   --   |    445
      Do.                 |   16  |   0.63  |  0.09  |  0.09 |   --   |    560
  Roast pork, loin        |   12  |   0.83  |  0.11  |  0.19 |   --   |   1035
  Pork, smoked ham        |   22  |   0.45  |  0.06  |  0.14 |   --   |    735
      Do.                 |   18  |   0.56  |  0.08  |  0.18 |   --   |    915
  Pork, fat salt          |   12  |   0.83  |  0.02  |  0.68 |   --   |   2950
  Codfish, dressed, fresh |   10  |   1.00  |  0.11  |   --  |   --   |    220
  Halibut, fresh          |   18  |   0.56  |  0.08  |  0.02 |   --   |    265
  Cod, salt               |    7  |   1.43  |  0.22  |  0.01 |   --   |    465
  Mackerel, salt, dressed |   10  |   1.00  |  0.13  |  0.20 |   --   |   1135
  Salmon, canned          |   12  |   0.83  |  0.18  |  0.10 |   --   |    760
  Oysters, solids,        |       |         |        |       |        |
      50 cents per quart  |   25  |   0.40  |  0.02  |   --  |  0.01  |     90
      35 cents per quart  |   18  |   0.56  |  0.03  |  0.01 |  0.02  |    125
  Lobster, canned         |   18  |   0.56  |  0.10  |  0.01 |   --   |    225
  Butter                  |   20  |   0.50  |  0.01  |  0.40 |   --   |   1705
      Do.                 |   25  |   0.40  |   --   |  0.32 |   --   |   1365
      Do.                 |   30  |   0.33  |   --   |  0.27 |   --   |   1125
  Eggs, 36 cents per dozen|   24  |   0.42  |  0.05  |  0.04 |   --   |    260
  Eggs, 24 cents per dozen|   16  |   0.63  |  0.07  |  0.06 |   --   |    385
  Eggs, 12 cents per dozen|    8  |   1.25  |  0.14  |  0.11 |   --   |    770
  Cheese                  |   16  |   0.63  |  0.16  |  0.20 |  0.02  |   1185
  Milk, 7 cents per quart | 3-1/2 |   2.85  |  0.09  |  0.11 |  0.14  |    885
  Milk, 6 cents per quart |    3  |   3.33  |  0.11  |  0.13 |  0.17  |   1030
  Wheat flour             |    3  |   3.33  |  0.32  |  0.03 |  2.45  |   5440
      Do.                 | 2-1/2 |   4.00  |  0.39  |  0.04 |  2.94  |   6540
  Corn meal, granular     | 2-1/2 |   4.00  |  0.31  |  0.07 |  2.96  |   6540
  Wheat breakfast food    | 7-1/2 |   1.33  |  0.13  |  0.02 |  0.98  |   2235
  Oat breakfast food      | 7-1/2 |   1.33  |  0.19  |  0.09 |  0.86  |   2395
  Oatmeal                 |    4  |   2.50  |  0.34  |  0.16 |  1.66  |   4500
  Rice                    |    8  |   1.25  |  0.08  |   --  |  0.97  |   2025
  Wheat bread             |    6  |   1.67  |  0.13  |  0.02 |  0.87  |   2000
      Do.                 |    5  |   2.00  |  0.16  |  0.02 |  1.04  |   2400
      Do.                 |    4  |   2.50  |  0.20  |  0.03 |  1.30  |   3000
  Rye bread               |    5  |   2.00  |  0.15  |  0.01 |  1.04  |   2340
  Beans, white, dried     |    5  |   2.00  |  0.35  |  0.03 |  1.16  |   3040
  Cabbage                 | 2-1/2 |   4.00  |  0.05  |  0.01 |  0.18  |    460
  Celery                  |    5  |   2.00  |  0.02  |   --  |  0.05  |    130
  Corn, canned            |   10  |   1.00  |  0.02  |  0.01 |  0.18  |    430
  Potatoes,               |       |         |        |       |        |
      90 cents per bushel |  1-1/2|   6.67  |  0.10  |  0.01 |  0.93  |   1970
      60 cents per bushel |    1  |  10.00  |  0.15  |  0.01 |  1.40  |   2950
      45 cents per bushel |   3/4 |  13.33  |  0.20  |  0.01 |  1.87  |   3935
  Turnips                 |    1  |  10.00  |  0.08  |  0.01 |  0.54  |   1200
  Apples                  |  1-1/2|   6.67  |  0.02  |  0.02 |  0.65  |   1270
  Bananas                 |    7  |   1.43  |  0.01  |  0.01 |  0.18  |    370
  Oranges                 |    6  |   1.67  |  0.01  |   --  |  0.13  |    250
  Strawberries            |    7  |   1.43  |   .01  |  0.01 |  0.09  |    215
  Sugar                   |    6  |   1.67  |   --   |   --  |  1.67  |   2920
  =============================================================================

It is to be noted in the table that, ordinarily, for the same amount of
money the most nutrients can be obtained in the form of milk, cheese,
sugar, and beans, corn meal, wheat flour, oatmeal, and cereals in bulk.
While meats supply protein liberally, they fail to furnish carbohydrates
as the vegetables. As discussed in the chapter on Dietary Studies of
Families, unnecessarily expensive foods are often used, resulting either
in lack of nutrients or unbalanced rations.

EXAMPLES

1. Compute the calories and the amounts of protein, fat, and
carbohydrates that can be procured for 25 cents in cheese selling for 18
cents per pound; how do these compare with the nutrients in eggs at 20
cents per dozen?

2. Which food furnishes the larger amount of nutrients, potatoes at 50
cents per bushel or flour at $6 per barrel?

3. How do beans at 10 cents per quart compare in nutritive value with
beef at 15 Cents per pound?

4. How does salt codfish at 10 cents per pound compare in nutritive
value with lamb chops at 15 cents per pound?

5. Compare in nutritive value cream at 25 cents per quart with butter at
30 cents per pound.

6. Calculate the composition and nutritive value of a cake made of
sugar, 8 oz.; butter, 4 oz.; eggs, 8 oz.; flour, 8 oz.; and milk, 4 oz.;
the baked cake weighs one and three fourths pounds.

AVERAGE COMPOSITION OF COMMON AMERICAN FOOD PRODUCTS

(From Farmer's Bulletin, No. 142, U. S. Dept. of Agr.)

  =============================================================================
                                |      |      |      |      |     |     | F
                                |      |      |      |      |   h |     | u p
                                |  R   |      |  P   |      | C y |     | e e
                                |  e   |  W   |  r   |      | a d |     | l r
                                |  f   |  a   |  o   |  F   | r r |  A  |
      Food Material             |  u   |  t   |  t   |  a   | b a |  s  | v P
      (as purchased)            |  s   |  e   |  e   |  t   | o t |  h  | a o
                                |  e   |  r   |  i   |      | - e |     | l u
                                |      |      |  n   |      |   s |     | u n
                                |      |      |      |      |     |     | e d
  ------------------------------+------+------+------+------+-----+-----+------
                                |      |      |      |      |     |     | Calo-
         ANIMAL FOOD            |  %   |  %   |  %   |  %   |  %  |  %  | ries
                                |      |      |      |      |     |     |
  Beef, fresh:                  |      |      |      |      |     |     |
    Chuck ribs                  | 16.3 | 52.6 | 15.5 | 15.0 |  -- | 0.8 |  910
    Flank                       | 10.2 | 54.0 | 17.0 | 19.0 |  -- | 0.7 | 1105
    Loin                        | 13.3 | 52.5 | 16.1 | 17.5 |  -- | 0.9 | 1025
    Porterhouse steak           | 12.7 | 52.4 | 19.1 | 17.9 |  -- | 0.8 | 1100
    Sirloin steak               | 12.8 | 54.0 | 16.5 | 16.1 |  -- | 0.9 |  975
    Neck                        | 27.6 | 45.9 | 14.5 | 11.9 |  -- | 0.7 | 1165
    Ribs                        | 20.8 | 43.8 | 13.9 | 21.2 |  -- | 0.7 | 1135
    Rib rolls                   |  --  | 63.9 | 19.3 | 16.7 |  -- | 0.9 | 1055
    Round                       |  7.2 | 60.7 | 19.0 | 12.8 |  -- | 1.0 |  890
    Rump                        | 20.7 | 45.0 | 13.8 | 20.2 |  -- | 0.7 | 1090
    Shank, fore                 | 36.9 | 42.9 | 12.8 |  7.3 |  -- | 0.6 |  545
    Shoulder and clod           | 16.4 | 56.8 | 16.4 |  9.8 |  -- | 0.9 |  715
    Fore quarter                | 18.7 | 49.1 | 14.5 | 17.5 |  -- | 0.7 |  995
    Hind quarter                | 15.7 | 50.4 | 15.4 | 18.3 |  -- | 0.7 | 1045
  Beef, corned, canned,         |      |      |      |      |     |     |
        pickled, dried:         |      |      |      |      |     |     |
    Corned beef                 |  8.4 | 49.2 | 14.3 | 23.8 |  -- | 4.6 | 1245
    Tongue, pickled             |  6.0 | 58.9 | 11.9 | 19.2 |  -- | 4.3 | 1010
    Dried, salted, and smoked   |  4.7 | 53.7 | 26.4 |  6.9 |  -- | 8.9 |  790
    Canned boiled beef          |  --  | 51.8 | 25.5 | 22.5 |  -- | 1.3 | 1410
    Canned corned beef          |  --  | 51.8 | 26.3 | 18.7 |  -- | 4.0 | 1270
  Veal:                         |      |      |      |      |     |     |
    Breast                      | 21.3 | 52.0 | 15.4 | 11.0 |  -- | 0.8 |  745
    Leg                         | 14.2 | 60.1 | 15.5 |  7.9 |  -- | 0.9 |  625
    Leg cutlets                 |  3.4 | 68.3 | 20.1 |  7.5 |  -- | 1.0 |  695
    Fore quarter                | 24.5 | 54.2 | 15.1 |  6.0 |  -- | 0.7 |  535
    Hind quarter                | 20.7 | 56.2 | 16.2 |  6.6 |  -- | 0.8 |  580
  Mutton:                       |      |      |      |      |     |     |
    Flank                       |  9.9 | 39.0 | 13.8 | 36.9 |  -- | 0.6 | 1770
    Leg, hind                   | 18.4 | 51.2 | 15.1 | 14.7 |  -- | 0.8 |  890
    Loin chops                  | 16.0 | 42.0 | 13.5 | 28.3 |  -- | 0.7 | 1415
    Fore quarter                | 21.2 | 41.6 | 12.3 | 24.5 |  -- | 0.7 | 1235
    Hind quarter, without       | 17.2 | 45.4 | 13.8 | 23.2 |  -- | 0.7 | 1210
         tallow                 |      |      |      |      |     |     |
  Lamb:                         |      |      |      |      |     |     |
    Breast                      | 10.1 | 45.5 | 15.4 | 19.1 |  -- | 0.8 | 1075
    Leg, hind                   | 17.4 | 52.9 | 15.9 | 13.6 |  -- | 0.9 |  860
  Pork, fresh:                  |      |      |      |      |     |     |
    Ham                         | 10.7 | 48.0 | 13.5 | 25.9 |  -- | 0.8 | 1320
    Loin chops                  | 19.7 | 41.8 | 13.4 | 24.2 |  -- | 0.8 | 1245
    Shoulder                    | 12.4 | 44.9 | 12.0 | 29.8 |  -- | 0.7 | 1450
    Tenderloin                  |  --  | 66.5 | 18.9 | 13.0 |  -- | 1.0 |  895
  Pork, salted, cured, pickled: |      |      |      |      |     |     |
    Ham, smoked                 | 13.6 | 34.8 | 14.2 | 33.4 |  -- | 4.2 | 1635
    Shoulder, smoked            | 18.2 | 36.8 | 13.0 | 26.6 |  -- | 5.5 | 1335
    Salt pork                   |  --  |  7.9 |  1.9 | 86.2 |  -- | 3.9 | 3555
    Bacon, smoked               |  7.7 | 17.4 |  9.1 | 62.2 |  -- | 4.1 | 2715
  Sausage:                      |      |      |      |      |     |     |
    Bologna                     |  3.3 | 55.2 | 18.2 | 19.7 |  -- | 3.8 | 1155
    Pork                        |  --  | 39.8 | 13.0 | 44.2 |  1.1| 2.2 | 2075
    Frankfort                   |  --  | 57.2 | 19.6 | 18.6 |  1.1| 3.4 | 1155
  Soups:                        |      |      |      |      |     |     |
    Celery, cream of            |  --  | 88.6 |  2.1 |  2.8 |  5.0| 1.5 |  235
    Beef                        |  --  | 92.9 |  4.4 |  0.4 |  1.1| 1.2 |  120
    Meat stew                   |  --  | 84.5 |  4.6 |  4.3 |  5.5| 1.1 |  365
    Tomato                      |  --  | 90.0 |  1.8 |  1.1 |  5.6| 1.5 |  185
  Poultry:                      |      |      |      |      |     |     |
    Chicken, broilers           | 41.6 | 43.7 | 12.8 |  1.4 |  -- | 0.7 |  305
    Fowls                       | 25.9 | 47.1 | 13.7 | 12.3 |  -- | 0.7 |  765
    Goose                       | 17.6 | 38.5 | 13.4 | 29.8 |  -- | 0.7 | 1475
    Turkey                      | 22.7 | 42.4 | 16.1 | 18.4 |  -- | 0.8 | 1060
  Fish:                         |      |      |      |      |     |     |
    Cod, dressed                | 29.9 | 58.5 | 11.1 |  0.2 |  -- | 0.8 |  220
    Halibut, steaks or sections | 17.7 | 61.9 | 15.3 |  4.4 |  -- | 0.9 |  475
    Mackerel, whole             | 44.7 | 40.4 | 10.2 |  4.2 |  -- | 0.7 |  370
    Perch, yellow dressed       | 35.1 | 50.7 | 12.8 |  0.7 |  -- | 0.9 |  275
    Shad, whole                 | 50.1 | 35.2 |  9.4 |  4.8 |  -- | 0.7 |  380
    Shad, roe                   |   -- | 71.2 | 20.9 |  3.8 |  2.6| 1.5 |  600
  Fish, preserved:              |      |      |      |      |     |     |
    Cod, salt                   | 24.9 | 40.2 | 16.0 |  0.4 |  -- |18.5 |  325
    Herring, smoked             | 44.4 | 19.2 | 20.5 |  8.8 |  -- | 7.4 |  755
  Fish, canned                  |      |      |      |      |     |     |
    Salmon                      |   -- | 63.5 | 21.8 | 12.1 |  -- | 2.6 |  915
    Sardines                    |[A]5.0| 53.6 | 23.7 | 12.1 |  -- | 5.3 |  950
  Shellfish:                    |      |      |      |      |     |     |
    Clams                       |  --  | 80.8 | 10.6 | 1.1  | 5.2 |  2.3|  340
    Crabs                       | 52.4 | 36.7 |  7.9 | 0.9  | 0.6 |  1.5|  200
    Lobsters                    | 61.7 | 30.7 |  5.9 | 0.7  | 0.2 |  0.8|  145
  Eggs: Hen's eggs           [B]|11.2  | 65.5 | 13.1 | 9.3  | --  |  0.9|  635
  Dairy products, etc.:         |      |      |      |      |     |     |
    Butter                      |  --  | 11.0 |  1.0 |85.0  | --  |  3.0| 3410
    Whole milk                  |  --  | 87.0 |  3.3 | 4.0  | 5.0 |  0.7|  310
    Skim milk                   |  --  | 90.5 |  3.4 | 0.3  | 5.1 |  0.7|  165
    Buttermilk                  |  --  | 91.0 |  3.0 | 0.5  | 4.8 |  0.7|  160
    Condensed milk              |  --  | 26.9 |  8.8 | 8.3  |54.1 |  1.9| 1430
    Cream                       |  --  | 74.0 |  2.5 |18.5  | 4.5 |  0.5|  865
    Cheese, Cheddar             |  --  | 27.4 | 27.7 |36.8  | 4.1 |  4.0| 2075
    Cheese, full cream          |  --  | 34.2 | 25.9 |33.7  | 2.4 |  3.8| 1885
                                |      |      |      |      |     |     |
  VEGETABLE FOOD                |      |      |      |      |     |     |
                                |      |      |      |      |     |     |
  Flour, meal, etc.:            |      |      |      |      |     |     |
    Entire wheat flour          |  --  | 11.4 | 13.8 | 1.9  |71.9 |  1.0| 1650
    Graham flour                |  --  | 11.3 | 13.3 | 2.2  |71.4 |  1.8| 1645
    Wheat flour, patent         |      |      |      |      |     |     |
        roller process          |      |      |      |      |     |     |
      High-grade and medium     |  --  | 12.0 | 11.4 | 1.0  |75.1 |  0.5| 1635
      Low grade                 |  --  | 12.0 | 14.0 | 1.9  |71.2 |  0.9| 1640
    Macaroni, vermicelli, etc   |  --  | 10.3 | 13.4 | 0.9  |74.1 |  1.3| 1645
    Wheat breakfast food        |  --  |  9.6 | 12.1 | 1.8  |75.2 |  1.3| 1680
    Buckwheat flour             |  --  | 13.6 |  6.4 | 1.2  |77.9 |  0.9| 1605
    Rye flour                   |  --  | 12.9 |  6.8 | 0.9  |78.7 |  0.7| 1620
    Corn meal                   |  --  | 12.5 |  9.2 | 1.9  |75.4 |  1.0| 1635
    Oat breakfast food          |  --  |  7.7 | 16.7 | 7.3  |66.2 |  2.1| 1800
    Rice                        |  --  | 12.3 |  8.0 | 0.3  |79.0 |  0.4| 1620
    Tapioca                     |  --  | 11.4 |  0.4 | 0.1  |88.0 |  0.1| 1650
    Starch                      |  --  |  --  |  --  | --   |90.0 |  -- | 1675
  Bread, pastry, etc.:          |      |      |      |      |     |     |
    White bread                 |  --  | 35.3 |  9.2 | 1.3  |53.1 |  1.1| 1200
    Brown bread                 |  --  | 43.6 |  5.4 | 1.8  |47.1 |  2.1| 1040
  Bread, pastry, etc.:          |      |      |      |      |     |     |
   Graham bread                 |  --  | 35.7 |  8.9 |   1.8| 52.1| 1.5 | 1195
  Whole wheat bread             |  --  | 38.4 |  9.7.|   0.9| 49.7| 1.3 | 1130
  Rye bread                     |  --  | 35.7 |  9.0.|   0.6| 53.2| 1.5 | 1170
  Cake                          |  --  | 19.9 |  6.3.|   9.0| 63.3| 1.5 | 1630
  Cream crackers                |  --  |  6.8 |  9.7.|  12.1| 69.7| 1.7 | 1925
  Oyster crackers               |  --  |  4.8 | 11.3.|  10.5| 70.5| 2.9 | 1910
  Soda crackers                 |  --  |  5.9 |  9.8.|   9.1| 73.1| 2.1 | 1875
                                |      |      |      |      |     |     |
  Sugars, etc.:                 |      |      |      |      |     |     |
                                |      |      |      |      |     |     |
  Molasses                      |  --  |  --  |  --  |   -- | 70.0| --  | 1225
  Candy[C]                      |  --  |  --  |  --  |   -- | 96.0| --  | 1680
  Honey                         |  --  |  --  |  --  |   -- | 81.0| --  | 1420
  Sugar, granulated             |  --  |  --  |  --  |   -- |100.0| --  | 1750
  Maple sirup                   |  --  |  --  |  --  |   -- | 71.4| --  | 1250
                                |      |      |      |      |     |     |
  Vegetables:[D]                |      |      |      |      |     |     |
  Beans, dried                  |  --  | 12.6 | 22.5.|   1.8| 59.6| 3.5 | 1520
  Beans, Lima, shelled          |  --  | 68.5 |  7.1.|   0.7| 22.0| 1.7 |  540
  Beans, string                 |  7.0 | 83.0 |  2.1.|   0.3|  6.9| 0.7 |  170
  Beets                         | 20.0 | 70.0 |  1.3.|   0.1|  7.7| 0.9 |  160
  Cabbage                       | 15.0 | 77.7 |  1.4.|   0.2|  4.8| 0.9 |  115
  Celery                        | 20.0 | 75.6 |  0.9.|   0.1|  2.6| 0.8 |   65
  Corn, green (sweet),          |      |      |      |      |     |     |
          edible portion        |  --  | 75.4 |  3.1 |   1.1| 19.7| 0.7 |  440
  Cucumbers                     | 15.0 | 81.1 |  0.7.|   0.2|  2.6| 0.4 |   65
  Lettuce                       | 15.0 | 80.5 |  1.0.|   0.2|  2.5| 0.8 |   65
  Mushrooms                     | --   | 88.1 |  3.5 |   0.4|  6.8| 1.2 |  185
  Onions                        | 10.0 | 78.9 |  1.4.|   0.3|  8.9| 0.5 |  190
  Parsnips                      | 20.0 | 66.4 |  1.3.|   0.4| 10.8| 1.1 |  230
  Peas _(Pisum sativum),_       |      |      |      |      |     |     |
      dried.                    |  --  |  9.5 | 24.6 |   1.0| 62.0| 2.9 | 1565
      shelled                   |  --  | 74.6 |  7.0 |   0.5| 16.9| 1.0 |  440
  Cowpeas, dried                |  --  | 13.0 | 21.4.|   1.4| 60.8| 3.4 | 1505
  Potatoes                      | 20.0 | 62.6 |  1.8.|   0.1| 14.7| 0.8 |  295
  Vegetables:                   |      |      |      |      |     |     |
    Rhubarb                     | 40.0 | 56.6 |  0.4 |  0.4 |  2.2| 0.4 |   60
    Sweet potatoes              | 20.0 | 55.2 |  1.4 |  0.6 | 21.9| 0.9 |  440
    Spinach                     |  --  | 92.3 |  2.1 |  0.3 |  3.2| 2.1 |   95
    Squash                      | 50.0 | 44.2 |  0.7 |  0.2 |  4.5| 0.4 |  100
    Tomatoes                    |  --  | 94.3 |  0.9 |  0.4 |  3.9| 0.5 |  100
    Turnips                     | 30.0 | 62.7 |  0.9 |  0.1 |  5.7| 0.6 |  120
  Vegetables, canned:           |      |      |      |      |     |     |
    Baked beans                 |  --  | 68.9 |  6.9 |  2.5 | 19.6| 2.1 |  555
    Peas _(Pisum sativum),_     |      |      |      |      |     |     |
        green                   |  --  | 85.3 |  3.6 |  0.2 |  9.8| 1.1 |  235
    Corn, green                 |  --  | 76.1 |  2.8 |  1.2 | 19.0| 0.9 |  430
    Succotash                   |  --  | 75.9 |  3.6 |  1.0 | 18.6| 0.9 |  425
    Tomatoes                    |  --  | 94.0 |  1.2 |  0.2 |  4.0| 0.6 |   95
  Fruits, berries, etc.,        |      |      |      |      |     |     |
              fresh: [E]        |      |      |      |      |     |     |
    Apples                      | 25.0 | 63.3 |  0.3 |  0.3 | 10.8| 0.3 |  190
    Bananas                     | 35.0 | 48.9 |  0.8 |  0.4 | 14.3| 0.6 |  260
    Grapes                      | 25.0 | 58.0 |  1.0 |  1.2 | 14.4| 0.4 |  295
    Lemons                      | 30.0 | 62.5 |  0.7 |  0.5 |  5.9| 0.4 |  125
    Muskmelons                  | 50.0 | 44.8 |  0.3 |  --  |  4.6| 0.3 |   80
    Oranges                     | 27.0 | 63.4 |  0.6 |  0.1 |  8.5| 0.4 |  150
    Pears                       | 10.0 | 76.0 |  0.5 |  0.4 | 12.7| 0.4 |  230
    Persimmons, edible portion  |  --  | 66.1 |  0.8 |  0.7 | 31.5| 0.9 |  550
    Raspberries                 |  --  | 85.8 |  1.0 |  --  | 12.6| 0.6 |  220
    Strawberries                |  5.0 | 85.9 |  0.9 |  0.6 |  7.0| 0.6 |  150
    Watermelons                 | 59.4 | 37.5 |  0.2 |  0.1 |  2.7| 0.1 |   50
  Fruits, dried:                |      |      |      |      |     |     |
    Apples                      |  --  | 28.1 |  1.6 |  2.2 | 66.1| 2.0 | 1185
    Apricots                    |  --  | 29.4 |  4.7 |  1.0 | 62.5| 2.4 | 1125
    Dates                       | 10.0 | 13.8 |  1.9 |  2.5 | 70.6| 1.2 | 1275
  Fruits, dried:                |      |      |      |      |     |     |
    Rhubarb                     | 40.0 | 56.6 |  0.4 |  0.4 |  2.2| 0.4 |   60
                                |      |      |      |      |     |     |
    Figs                        |  --  | 18.8 |  4.3 |  0.3 | 74.2| 2.4 | 1280
    Raisins                     | 10.0 | 13.1 |  2.3 |  3.0 | 68.5| 3.1 | 1265
    Nuts:                       |      |      |      |      |     |     |
    Almonds                     | 45.0 |  2.7 | 11.5 | 30.2 |  9.5| 1.1 | 1515
    Brazil nuts                 | 49.6 |  2.6 |  8.6 | 33.7 |  3.5| 2.0 | 1485
    Butternuts                  | 86.4 |  0.6 |  3.8 |  8.3 |  0.5| 0.4 |  385
    Chestnuts, fresh            | 16.0 | 37.8 |  5.2 |  4.5 | 35.4| 1.1 |  915
    Chestnuts, dried            | 24.0 |  4.5 |  8.1 |  5.3 | 56.4| 1.7 | 1385
    Cocoanuts                [F]| 48.8 |  7.2 |  2.9 | 25.9 | 14.3| 0.9 | 1295
    Cocoanut, prepared          |  --  |  3.5 |  6.3 | 57.4 | 31.5| 1.3 | 2865
    Filberts                    | 52.1 |  1.8 |  7.5 | 31.3 |  6.2| 1.1 | 1430
    Hickory nuts                | 62.2 |  1.4 |  5.8 | 25.5 |  4.3| 0.8 | 1145
    Pecans, polished            | 53.2 |  1.4 |  5.2 | 33.3 |  6.2| 0.7 | 1465
    Peanuts                     | 24.5 |  6.9 | 19.5 | 29.1 | 18.5| 1.5 | 1775
    Piñon _(Pinus edulis)_      | 40.6 |  2.0 |  8.7 | 36.8 | 10.2| 1.7 | 1730
    Walnuts, black              | 74.1 |  0.6 |  7.2 | 14.6 |  3.0| 0.5 |  730
    Walnuts, English            | 58.1 |  1.0 |  6.9 | 26.6 |  6.8| 0.6 | 1250
  Miscellaneous:                |      |      |      |      |     |     |
    Chocolate                   |  --  |  5.9 | 12.9 | 48.7 | 30.3| 2.2 | 5625
    Cocoa, powdered             |  --  |  4.6 | 21.6 | 28.9 | 37.7| 7.2 | 2160
    Cereal coffee, infusion     |      |      |      |      |     |     |
       (1 part boiled in        |      |      |      |      |     |     |
       20 parts water)[G]       |  --  | 98.2 |  0.2 |  --  |  1.4| 0.2 |   30
  =============================================================================

[Footnote A: Refuse, oil.]
[Footnote B: Refuse, shell.]

[Footnote C: Plain confectionery not containing nuts, fruit, or
chocolate.]

[Footnote D: Such vegetables as potatoes, squash, beets, etc., have a
certain amount of inedible material, skin, seeds, etc The amount varies
with the method of preparing the vegetables, and cannot be accurately
estimated The figures given for refuse of vegetables, fruits, etc., are
assumed to represent approximately the amount of refuse in these foods
as ordinarily prepared.]

[Footnote E: Fruits contain a certain proportion of inedible materials,
as skin, seeds, etc., which are properly classed as refuse. In some
fruits, as oranges and prunes, the amount rejected in eating is
practically the same as refuse. In others, as apples and pears, more or
less of the edible material is ordinarily rejected with the skin and
seeds and other inedible portions. The edible material which is thus
thrown away, and should properly be classed with the waste, is here
classed with the refuse. The figures for refuse here given represent, as
nearly as can be ascertained, the quantities ordinarily rejected.]

[Footnote F: Milk and shell.]

[Footnote G: The average of five analyses of cereal coffee grain is:
Water 6.2, protein 13.3, fat 3.4, carbohydrates 72.6, and ash 4.5 per
cent. Only a portion of the nutrients, however, enter into the infusion.
The average in the table represents the available nutrients in the
beverage. Infusions of genuine coffee and of tea like the above contain
practically no nutrients.]

CHAPTER XVII

DIETARY STUDIES

244. Object of Dietary Studies.--The quantity of food which different
families purchase varies between wide limits; a portion being lost
mechanically in preparation and a still larger and more variable amount
in the refuse and non-edible parts. If a record is made of all foods
purchased and the waste and non-edible portions are deducted, the
nutrients consumed by a family may be calculated by multiplying the
weight of each food by the average composition. If such calculations be
made, it will be found that in some families nearly a half pound per day
of both protein and fat is consumed by adults, while in other families
less than half of this amount is used. The object of dietary studies is
to determine the source, cost, composition, and nutritive value of the
foods consumed by different families; they also enable comparisons to be
made of the amounts of nutrients purchased. Extensive dietary studies
have been made by the United States Department of Agriculture, and the
results have been published in various bulletins.[76]

245. Wide and Narrow Rations.--When the amount of carbohydrates in a
ration is small in comparison with the protein, it is called a narrow
ration, while a wide ration is one in which the carbohydrates are much
in excess of the protein. When a ration contains 0.40 of a pound of
protein, 0.40 of a pound of fat, and 1 pound of carbohydrates, it has a
nutritive ratio of 1 to 4.8 and is a narrow ration. To calculate the
nutritive ratio, the fat is multiplied by 2-1/4, the product added to
the carbohydrates, and this sum divided by the protein. It is not
possible to designate accurately the amount of protein and other
nutrients that should be in the daily ration of all persons, because the
needs of the body vary so with different individuals. Hard and fast
rules governing the amounts of nutrients to be consumed cannot as yet be
formulated, as our knowledge of the subject is too limited. It is known
that both excessive and scant amounts are alike injurious. While the
appetite may indicate either hunger or satiety, it alone cannot always
be relied upon as a safe guide for determining the amount and kind of
food to consume, although the demands of appetite should not be
disregarded until it has been demonstrated beyond a doubt that it is not
voicing the needs of nature. There has been a tendency which perhaps was
a survival of the Puritanical ideas of the early days to stamp as
hurtful whatever seemed desirable and pleasant; as examples might be
cited the craving for water by fever patients, and for sugar by growing
children, which have now been proven to be normal demands of nature.

246. Dietary Standards.--As a result of a large number of dietary
studies and digestion experiments, dietary standards have been
prepared. Atwater in this country and Voit in Germany have proposed such
standards for men employed at different kinds of labor, as follows:

  ==========================================================================
                                   |Protein| Fat|Carbo-  | Fuel   |Nutritive
                                   |       |    |hydrates| Value  |
  ---------------------------------|-------|----|-----------------|---------
                                   |  lb.  | lb.|   lb.  |Calories| Ratio
  Man with little physical exercise| 0.20  |0.20|  0.66  |  2450  |  5.5
  Man with light muscular work     | 0.22  |0.22|  0.77  |  2800  |  5.7
  Man with moderate muscular work  | 0.28  |0.28|  0.99  |  3520  |  5.8
  Man with active muscular work    | 0.33  |0.33|  1.10  |  4060  |  5.6
  Man with hard muscular work      | 0.39  |0.55|  1.43  |  5700  |  6.9
  ==========================================================================

In the table it will be seen that the quantity of nutrients increases
with the labor to be performed. In order to secure the necessary heat
and energy, rations for men at heavy labor contain proportionally more
fat and carbohydrates than are required for light work. All dietary
standards, however, should be regarded as tentative only. Opinions
differ greatly on different points; for example, as to the amount of
protein a ration should contain. This is a matter that can be determined
only from extended investigations under a variety of conditions, and as
yet results are too meager to formulate other than tentative standards.
Chittenden has found that the body can be sustained on very much less
protein than is called for in the standard ration.[77] The amount of
protein in the ration should be ample to sustain the body weight and
maintain a nitrogen equilibrium; that is, the income and outgo of
nitrogen from the body should be practically equal.

[Illustration: FIG. 58.--DIETARIES AND DIETARY
STANDARDS.

(From Office of Experiment Stations Bulletin.)]

     "While one freely admits that health and a large measure of
     muscular strength may be maintained upon a minimum supply of
     protein, yet I think that a dispassionate survey of mankind will
     show that races which adopt such a diet are lacking in what, for
     want of a better word, one can only describe as energy." [28]

On the other hand, excessive and unnecessarily large amounts of protein
are sometimes consumed, adding greatly to the cost of the ration and
necessitating additional labor on the part of the body for its
elimination.

247. Number of Meals per Day.--Some persons advocate two meals per day
rather than three, but dietary studies show that the best results are
secured when the food is divided among three rather than two meals, and
with a two-meal system the tendency is to consume a larger total amount
of food than when three meals are eaten. It is not essential that the
food be equally divided among the three meals. Any one of them may be
lighter or more substantial as the habits and inclinations of the
individual dictate. If it is found necessary to reduce the total
quantity of food consumed, this may be done by a proportional reduction
of each of the meals, or of any one of them instead of decreasing the
number of meals per day. The occasional missing of a meal is sometimes
beneficial, in cases of digestion disorders, but the ordinary
requirements of persons in normal health who have either mental or
physical labor to perform are best met when three meals per day are
consumed, as this insures an even supply of nutrients. For persons of
sedentary habits, the kind and quantity of food at each meal must be
regulated largely by the individual from knowledge based on personal
experience.

     "In the matter of diet every man must, in the last resort, be a law
     unto himself; but he should draw up his dietetic code intelligently
     and apply it honestly, giving due heed to the warnings which nature
     is sure to address to him should he at any time transgress."[28]

If there is trouble in digesting the food, it is well to study the other
habits of life along with the food question, for it may be the
difficulty arises from some other cause, and would be remedied by more
exercise and fresh air, avoiding rush immediately after meals, more
thorough mastication, or less worry. It is a serious matter to shut off
the supply of food from a person not suffering from some disease and who
is working; as well cut off the supply of fuel from a furnace and then
expect a full amount of energy and heat. But unlike the furnace, when
the human body is deprived of needed nutrients it preys upon itself and
uses up its reserve that should be drawn upon only in cases of illness
or extreme nervous strain. Some persons live in such a way as to never
have any reserve of strength and energy to call upon but use up each day
all the body can produce and so become physical bankrupts when they
should be in their prime. Food is required for the production of nerve
energy as well as physical energy.[78]

248. Mixed Dietary Desirable.--Experiments in the feeding of farm
animals show that the best results come from the combination of a number
of foods to form a mixed ration, rather than from the use of one food
alone,[79] for in this way the work of digestion is more evenly
distributed, and a higher degree of efficiency is secured from the foods
consumed. The same is true in human feeding; the best results are
secured from a mixed diet. Ordinarily, about two fifths of the nutrients
of a ration are derived from animal and three fifths from vegetable
sources.

249. Animal and Vegetable Foods; Economy of Production.--Animal foods
can never compete in cheapness of the nutrients with cereals and
vegetables, as it takes six to eight pounds or more of a cereal,
together with forage crops, to make a pound of meat. Hence the returns
in food value are very much larger from the direct use of the cereals as
human food, than from the feeding of cereals to cattle and the use of
the meat. As the population of a country increases, and foods
necessarily become more expensive, cereals are destined to replace
animal foods to a great extent, solely as a matter of economy.

250. Food Habits.--Long-established dietary habits and customs are not
easily changed, and when the body becomes accustomed to certain foods,
substitution of others, although equally valuable, may fail to give
satisfactory results. For example, immigrants from southern Europe
demand foods with which they are familiar, as macaroni, olive oil, and
certain kinds of cheese, foods which are generally imported and more
expensive than the staples produced in this country,[80] and when they
are compelled to live on other foods, even though they have as many
nutrients, they complain of being underfed. Previously acquired food
habits appear to affect materially the process of digestion and
assimilation. Sudden and pronounced change in the feeding of farm
animals is attended with unsatisfactory results, and whenever changes
are made in the food of either humans or animals they should be gradual
rather than radical.

251. Underfed Families.--As the purchasing of food is often done by
inexperienced persons, palatability rather than nutritive value is made
the basis of choice. Dietary studies show that because of lack of
knowledge of the nutritive value of foods, whole families are often
underfed. Particularly is this true where the means for purchasing foods
are limited. In dietary studies among poor families in New York
City,[81] the United States Department of Agriculture notes: "It is
quite evident that what is needed among these families more than
anything else is instruction in the way to make the little they have go
the farthest." Some classes of the rich too are equally liable to be
underfed, as they are more prone to food notions and are able to indulge
them. Among the children of the rich are found some as poorly nourished
as among the poor.

252. Cheap and Expensive Foods.--Among the more expensive items of a
ration are meats, butter, and canned fruits. The difference in
composition and nutritive value between various cuts of meat is small,
being largely physical, and affecting taste and flavor rather than
nutritive value. Expensive cuts of meat, high-priced breakfast cereals,
tropical fruits and foods which impart special flavors, add little in
the way of nutritive value to the ration, but greatly enhance the cost
of living. Ordinarily the cheapest foods are corn meal, wheat flour and
bread, milk, beans, cheese, sugar, and potatoes.[7] The amount of animal
and vegetable foods to combine with these to form a balanced ration may
be governed largely by personal preference or cost, as there is little
difference in nutritive value. The selection of foods on the basis of
cost and nutritive value is discussed in Chapter XVI.

253. Food Notions.--Many erroneous ideas exist as to the nutritive
value of foods, and often wholesome and valuable foods are discriminated
against because of prejudice. Skim milk is usually regarded as
containing little if any nourishing material, when in reality it has a
high protein content, and can be added to other foods to increase their
nutritive value. The less expensive cuts of meat contain more total
nutrients than many of the more expensive ones. Beef extracts have been
erroneously said to contain more nutrients than beef,[51] and mushrooms
to be equal in value of beefsteak; chemical analyses fail to confirm
either statement. The banana also has been overestimated as to food
value, and while it contains more nutrients than many fruits, it is not
the equal of cereals, as has been claimed.[82] Cocoa, although a
valuable beverage, adds but little in the way of nutrients to a ration
unless it is made with milk. The value of a food should be based upon
its composition as determined by chemical analysis, its digestibility as
founded upon digestion experiments, and its palatability and mechanical
structure. Food notions have, in many instances, been the cause of
banishing from the dietary wholesome and nutritious foods, of greatly
increasing the cost of living, as well as of promulgating incorrect
ideas in regard to foods, so that individuals and in some cases entire
families have suffered from improper or insufficient food.

254. Dietary of Two Families Compared.--A dietary study often reveals
ways in which it is possible to improve the ration in kinds and amounts
of food, and sometimes at less expense. The following dietaries of two
families for the same period show that one family expends over twice as
much in the purchase of foods as the other family, and yet the one whose
food costs the less actually secures the larger amount of nutritive
material and is better fed than the family where more money is expended
for food.[13]

  FOOD CONSUMED, ONE WEEK

  FAMILY No. 1

  20 loaves of bread                               $1.00
  10 to 12 lb. loin steak, or meat of similar cost  2.00
  20 to 25 lb. rib roast, or similar meat           4.40
  4 lb. high-priced cereal breakfast food, 20 ct.   0.80
  Cake and pastry purchased                         3.00
  8 lb. butter, 30 ct.                              2.40
  Tea, coffee, spices, etc                          0.75
  Mushrooms                                         0.75
  Celery                                            1.00
  Oranges                                           2.00
  Potatoes                                          0.25
  Miscellaneous canned goods                        2.00
  Milk                                              0.50
  Miscellaneous foods                               2.00
  3 doz. eggs                                       0.60
                                                  $23.45

  FAMILY No. 2

  15 lb. flour, bread home-made (skim milk used)      $0.45
  Yeast, shortening and skim milk                      0.10
  10 lb. steak (round. Hamburger and some loin)        1.50
  10 lb. other meats, boiling pieces, rump roast, etc. 1.00
  5 lb. cheese, 16 cents                               0.80
  5 lb. oatmeal (bulk)                                 0.15
  5 lb. beans                                          0.25
  Home-made cake and pastry                            1.00
  6 lb. butter, 30 ct.                                 1.80
  3 lb. home-made shortening                           0.25
  Tea, coffee, and spices                              0.40
  Apples                                               0.50
  Prunes                                               0.25
  Potatoes                                             0.25
  Milk                                                 1.00
  Miscellaneous foods                                  1.00
  3 doz. eggs                                          0.60
                                                     $11.30

[Illustration: FIG. 59.--COST AND NUTRITIVE VALUE OF RATIONS.]

In comparing the foods used by the two families, it will be observed
that family No. 1 purchased their bread at the bakery at a cost of $
1.00, while the bread of family No. 2 was home-made, skim milk being
used in its preparation, the flour, milk, yeast, and shortening costing
about 55 cents. Family No. 1 consumed 10 pounds of expensive steaks,
family No. 2 consumed the same number of pounds, a portion being cheaper
cuts. Instead of the 20 pounds of roast or similar beef used by family
No. 1, only one half as much and cheaper cuts as boiling pieces, stew,
rump roast, etc., were used by family No. 2; 5 pounds of beans and 5
pounds of cheese taking the place of some of the meat. Family No. 1
consumed 4 pounds of high-priced cereal breakfast foods, supposing they
contained a larger amount of nutrients than were actually present. In
place of the 4 pounds of high-priced cereal breakfast foods of family
No. 1, family No. 2 used 5 pounds of oatmeal purchased in bulk. Family
No. 1 bought their cake and pastry for $3.00, while those of family No.
2 were home made and cost $1.00. Family No. 2 used 2 pounds less butter
per week because of the preparation and use of home-made shortening from
beef suet and milk. They also purchased a smaller amount of tea, coffee,
and spices than family No. 1. Family No. 2 consumed a larger quantity of
less expensive fruits and vegetables than family No. 1, who ate 75
cents' worth of mushrooms with the idea that they contained as much
protein as meat, but analyses show that mushrooms contain no more
nutrients than potatoes and similar vegetables. In place of the celery
and oranges, apples and prunes were used by family No. 2. The same
amount of potatoes was used by each. Fifty cents was spent for milk by
family No. 1 and $1.00 by family No. 2. The total amount expended for
food by family No. 1 was $23.45, while family No. 2 purchased a greater
variety of foods for $11.30, as well as foods containing more nutrients.
The approximate amounts of nutrients in the foods purchased by the two
families are given in the following table, from which it will be
observed that family No. 2 obtained a much larger amount of total
nutrients and was better fed at considerably less expense than family
No. 1.

NUTRIENTS IN FOODS CONSUMED.--FAMILY NO. 1

  =============================================
                   |PROTEIN| FAT |CARBOHYDRATES
                   |  LB.  | LB. |   LB.
  -------------------------|-----|-------------
  20 lb. bread     |  1.98 | 0.28| 11.42
  10 lb. loin steak|  1.59 | 1.76|   --
  20 lb. rib roast |  2.68 | 4.26|   --
  4 lb. cereals    |  0.42 | 0.06|  2.75
  8 lb. butter     |  0.04 | 6.80|   --
  25 lb. potatoes  |  0.45 | 0.03|  3.83
  20 lb. milk      |  0.70 | 0.80|  1.00
                   |-------|-----|-------------
                   |  7.86 |13.99| 19.00
  =============================================

  FAMILY NO. 2
  =====================================================
                           |PROTEIN| FAT |CARBOHYDRATES
                           |  LB.  | LB. |   LB.
  -------------------------|-------|-----|-------------
  15 lb. flour             |  1.89 | 0.12|  11.15
  5 lb. skim milk          |  0.16 | 0.01|   0.26
  10 lb. round steak       |  1.81 | 1.26|    --
  10 lb. beef              |  1.32 | 2.02|    --
  5 lb. cheese             |  1.40 | 1.75|    --
  5 lb. oatmeal            |  0.78 | 0.36|   3.40
  6 lb. butter             |  0.03 | 5.10|    --
  3 lb. shortening         |   --  | 2.55|    --
  3 lb. prunes             |  0.03 |  -- |   0.60
  25 lb. apples            |  0.12 |  -- |   2.50
  25 lb. potatoes          |  0.45 | 0.03|   3.83
  40 lb. milk              |  1.44 | 1.60|   1.90
  5 lb. beans              |  1.12 |  -- |   3.00
  -------------------------|-------|-----|------------------
                           | 10.55 |14.80|  26.64
  -------------------------|-------|-----|------------------
  Difference in nutrients  |
  in favor of family No. 2,|
  consuming the cheaper    |2.69  0.81  7.64
  combination of foods     |
  =====================================================

255. Food in its Relation to Mental and Physical Vigor.--When the body
is not properly supplied with food, the best results in the form of
productive work cannot be secured. There is a close relationship between
the nature of the food consumed and mental activity, also ability to
satisfactorily perform physical labor. "The productive power of the
individual as well as of the nation depends doubtless upon many factors
other than food, such as race, climate, habit, etc., but there is no
gainsaying the fact that diet has also a profound and direct influence
upon it."[83]

If the body is diseased, it cannot make the right uses of the food, and
often the food is blamed when the trouble is due primarily to other
causes. The fact that a diseased digestive tract is unable to utilize
some foods is no valid reason why these foods should be discarded in the
dietary of persons in normal health, particularly when the food is in no
way responsible for the disease.

Some diseases are most prevalent in the case of a restricted diet. A
change in the dietary of the Japanese navy greatly improved the health
of the sailors.

     "The prevalence of kakke or beriberi in the navy turned the
     attention of many medical specialists toward the problem of
     nutrition.... It was generally believed that there was some very
     close connection between the disease and the rice diet.... One
     outcome of these investigations was the passage of the food supply
     act of the navy in 1884. The ration provided in accordance with
     this act was sufficient to furnish an abundance of protein and
     energy.... Following the change of ration in 1884, the prevalence
     of the disease was very materially diminished, and at the end of
     three years cases of kakke were practically unknown among the
     marines."[83]

256. Dietary Studies in Public Institutions.--Dietary studies in
public institutions, as prisons, and asylums for the insane, show that
it is possible to secure greater variety of food containing a larger
amount of nutrients, and even at a reduction in cost.[84] In such
institutions it is important that the food should be not only ample in
amount, but wholesome and nutritious, as many of the inmates respond
both physically and mentally to an improved diet. For humanitarian as
well as economic reasons institutional dietetics should more generally
be placed under the supervision of skilled dietists.

CHAPTER XVIII

RATIONAL FEEDING OF MAN

257. Object.--Rational feeding of man has for its object the
regulation of the food supply in accord with the demands of the body. It
is based upon the same principles as the rational feeding of animals; in
each, the best results in the way of health, amount of labor performed,
and economy are secured when the body receives nutrients sufficient for
the production of heat and energy and for the repair of worn-out
tissues. Rational feeding is simply regulation of the food, both as to
kind and amount, to meet the needs of the body.[72]

258. Standard Rations.--In human feeding, as in animal feeding, it is
not possible to lay down hard and fast rules as to the quantity of
nutrients required for a standard ration.[85] As stated in the chapter
on Dietary Studies, such standards have been proposed, but they are to
be considered as tentative rather than absolute, for the amount of food
required by different persons must necessarily vary with the
individuality. While it is impossible to establish absolute standards,
any large variation from the provisional standards usually results in
lessened ability to accomplish work, ill health, or increased expense.

259. Amounts of Food Consumed.--The approximate amounts of some food
articles consumed per day are as follows:

  ===================================
          |   RANGE   | APPROXIMATE
          |           |AMOUNT IN LBS.
  --------|--------------------------
  Bread   |6 to 14 oz.| 0.50
  Butter  |2 to  5 oz.| 0.12
  Potatoes|8 to 16 oz.| 0.75
  Cheese  |1 to  4 oz.| 0.12
  Beans   |1 to  4 oz.| 0.12
  Milk    |8 to 32 oz.|  --
  Sugar   |2 to  5 oz.| 0.20
  Meats   |4 to 12 oz.| 0.25
  Oatmeal |1 to  4 oz.| 0.12
  ===================================

In the calculation of rations it is desirable that the amount of any
food article should not exceed that designated, unless for some special
reason it has been found the food can consistently be increased. The
amount of nutrients given in dietary standards is for one day, and the
nutrients may be divided among the three meals as desired. It is to be
noted that, ordinarily, the foods which supply carbohydrates are flour,
corn meal, cereal products, potatoes, beans, sugar, and milk; those
which supply fat are milk, butter, lard, and meats; and those which
supply protein in liberal amounts are beans, cheese, meats, oatmeal,
cereals, bread, and milk.

260. Average Composition of Foods.--The amounts of nutrients in foods
are determined from the average composition of the foods. These figures
for average composition are based upon analyses of a large number of
samples of food materials.[7] In individual cases it will be found that
foods may vary from the standards given; as for example, milk may
contain from 2.5 to 5 per cent of fat, while the protein and fat of
meats vary appreciably from the figures given for average composition.
With the cereals and vegetable foods, variations from the standards are
small. In the table, the composition of the food as purchased represents
all of the nutrients in the food, including those in the refuse,
trimmings, or waste, while the figures for the edible portion represent
the nutrients in the food after deducting what is lost as refuse. In
making calculations, the student should use the figures given for the
foods as purchased, unless the weights are of the edible portion only.
The figures in the table are on the basis of percentage amounts, or
nutrients in 100 pounds of food. By moving the decimal point two places
to the left, the figures will represent the nutrients in one pound, and
if this is multiplied by the number of pounds or fraction of a pound
used, the quantity of nutrients is secured. For example, suppose bread
contains 9.5 per cent of protein and 56 per cent of carbohydrates, 1
pound would contain 0.095 pound of protein, 0.56 pound of
carbohydrates; and 0.5 of a pound would contain approximately 0.05 pound
of protein and 0.28 pound of carbohydrates. In calculating rations, it
is not necessary to carry the figures to the third decimal place.

[Illustration: FIG. 60.--FOOD ARTICLES FOR A HUMAN RATION.]

261. Example of a Ration.--Suppose it is desired to calculate a ration
for a man at light muscular work. First, note the requirements in the
way of nutrients in the table "Dietary Standards," Section 246. Such a
ration should supply approximately 0.22 pound each of protein and fat,
and 0.77 pound of carbohydrates, and should yield 2800 calories. A trial
ration is made by combining the following:

  ==========================================================
                                                 | Pound
  Bread                                          |  0.50
  Butter                                         |  0.12
  Potatoes                                       |  0.75
  Milk                                           |  1.00
  Sugar                                          |  0.12
  Beef                                           |  0.25
  Ham                                            |  0.20
  Oatmeal                                        |  0.12
  Eggs                                           |  0.25
  ==========================================================

The quantities of nutrients in these food materials are approximately as
follows:

RATION FOR MAN AT MODERATE WORK

  ===================================================================
                           |      | PROTEIN | FAT  | C.H. |
                           | LB.  |   LB.   | LB.  | LB.  | CALORIES
  -------------------------+------+---------+------+------+----------
  Bread                    | 0.50 |   0.05  | 0.01 | 0.29 |    653
  Butter                   | 0.12 |    --   | 0.10 |  --  |    432
  Potato                   | 0.75 |   0.01  |  --  | 0.12 |    244
  Milk                     | 1.00 |   0.04  | 0.04 | 0.05 |    323
  Sugar                    | 0.12 |    --   |  --  | 0.12 |    192
  Beef (round)             | 0.25 |   0.05  | 0.03 |  --  |    218
  Ham                      | 0.20 |   0.03  | 0.07 |  --  |    331
  Oatmeal                  | 0.12 |   0.02  | 0.01 | 0.08 |    223
  Eggs                     | 0.25 |   0.03  | 0.03 |  --  |    164
  Squash                   | 0.20 |    --   |  --  | 0.01 |     25
                           |------+---------+------+------+----------
                           |      |   0.23  | 0.29 | 0.67 |   2805
  ===================================================================

It is to be noted that this ration contains approximately the amount of
protein called for in the standard ration, while the fat is slightly
more and the carbohydrates are less. The food value of the ration is
practically that called for in the standard. This ration is sufficiently
near the standard to supply the nutrient requirements of a man at light
muscular work. To supply palatability, some fruit and vegetables should
be added to the ration. These will contribute but little to the nutrient
content, but are necessary in order to secure health and the best
returns from the other foods, and as previously stated, they are not to
be estimated entirely upon the basis of nutrient content. A number of
food articles could be substituted in this ration, if desired, either in
the interests of economy, palatability, or personal preference.

262. Requisites of a Balanced Ration.--Reasonable combinations of
foods should be made to form balanced rations.[2] A number of foods slow
of digestion, or which require a large amount of intestinal work, should
not be combined; neither should foods which are easily digested and
which leave but little indigestible residue. After a ration has been
calculated and found to contain the requisite amount of nutrients, it
should be critically examined to see whether or not it fulfills the
following requirements:

     1. Economy and adaptability to the work required.

     2. Necessary bulk or volume.

     3. Desired physiological influence of the foods upon the digestive
     tract, whether constipating or laxative in character.

     4. Ease of digestion.

     5. Effect upon health. It is recognized that there are foods
     wholesome and nutritious, that cannot be used by some persons,
     while with others the same foods can be consumed with impunity.

As explained in the chapter on Dietary Studies, the nutrients should be
supplied from a number of foods rather than from a few, because it is
believed the various nutrients, particularly the proteins, are not
absolutely identical from all sources, or equal in nutritive value.

EXAMPLES

1. Calculate a ration for a man with little physical exercise.

2. Calculate a ration for a man at hard muscular labor, and give the
approximate cost of the ration.

3. Calculate the amounts of food and the nutrient requirements for a
family of seven for 10 days; five of the family to consume 0.8 as much
as an adult. Calculate the cost of the food; then calculate on the same
basis the probable cost of food for one year, adding 20 per cent for
fluctuation in market price and additional foods not included in the
list.

4. Weigh out the food articles used in problem No. 2, and apportion them
among three meals.

CHAPTER XIX

WATER

263. Importance.--Water is one of the most essential food materials.
It enters into the composition of the body, and without it the nutrients
of foods would be unavailable, and life could not be sustained. Water
unites chemically with various elements to form plant tissue and
supplies hydrogen and oxygen for the production of organic compounds
within the leaves of plants. In the animal economy it is not definitely
known whether or not water furnishes any of the elements of which the
tissues are composed, as the food contains liberal amounts of hydrogen
and oxygen; it is necessary mainly as the vehicle for distributing
nutrients in suspension and solution, and as a medium in which chemical,
physical, and physiological changes essential to life processes take
place. From a sanitary point of view, the condition of the water supply
is of great importance, as impure water seriously affects the health of
the consumer.[87]

264. Impurities in Water.--Waters are impure because of: (1) excessive
amounts of alkaline salts and other mineral compounds; (2) decaying
animal and vegetable matters which act chemically as poisons and
irritants, and which may serve as food for the development of
objectionable bacterial bodies; and (3) injurious bacteria. The most
common forms of impurities are excess of organic matter and bacterial
contamination. The sanitary condition of water is greatly influenced by
the character of the soil through which it flows and the extent to which
it has been polluted by surface drainage.[88]

[Illustration: FIG. 61.--DIRT AND IMPURITIES IN A SURFACE WELL WATER.]

265. Mineral Impurities.--- The mineral impurities of water are mainly
soluble alkaline and similar compounds dissolved by the water in passing
through various layers of soil and rock. When water contains a large
amount of sodium chloride, sodium sulphate or carbonate, or other
alkaline salts, it is termed an "alkali water." Where water passes
through soil that has been largely formed from the decay of rocks
containing alkaline minerals, the water dissolves some of these minerals
and becomes alkaline. The kind of alkali determines the character of the
water; in some cases it is sodium carbonate, which is particularly
objectionable. The continued use of strong alkali water causes digestion
disorders, because of the irritating action upon the digestive tract.
Hard waters are due to the presence of lime compounds. In regions where
limestone predominates, the carbon dioxid in water acts as a solvent,
producing hard waters. Waters that are hard on account of the presence
of calcium carbonate give a deposit when boiled, due to liberation of
the carbon dioxid which is the material that renders the lime soluble.
Calcium sulphate, or gypsum, on the other hand, imparts permanent
hardness. There is no deposit when such waters are boiled. A large
number of minerals are found in various waters, often sufficient in
amount to impart physiological properties. Water that is highly charged