And wash'd it from the clotted gore,
     And salved the splinter o'er and o'er.
     William of Deloraine, in trance,
     Whene'er she turn'd it round and round,
     Twisted, as if she gall'd his wound,
     Then to her maidens she did say,
     That he should be whole man and sound,

     (Canto iii, xxiii.)

and in Dryden's "Tempest" (V, 1) Ariel says:

     Anoint the Sword which pierc'd him with the Weapon-Salve,
     And wrap it close from Air till I have time
     To visit him again.

From Van Helmont comes the famous story of the new nose that dropped off
in sympathy with the dead arm from which it was taken, and the source
of the famous lines of Hudibras. As I have not seen the original story
quoted of late years it may be worth while to give it: "A certain
inhabitant of Bruxels, in a combat had his nose mowed off, addressed
himself to Tagliacozzus, a famous Chirurgein, living at Bononia, that he
might procure a new one; and when he feared the incision of his own arm,
he hired a Porter to admit it, out of whose arm, having first given
the reward agreed upon, at length he dig'd a new nose. About thirteen
moneths after his return to his own Countrey, on a sudden the ingrafted
nose grew cold, putrified, and within few days drops off. To those of
his friends that were curious in the exploration of the cause of this
unexpected misfortune, it was discovered, that the Porter expired,
neer about the same punctilio of time, wherein the nose grew frigid and
cadaverous. There are at Bruxels yet surviving, some of good repute, that
were eye-witnesses of these occurrences."(18)

     (18) Charleton:  Of the Magnetic Cure of Wounds, London, 1650, p.
     13.

Equally in the history of science and of medicine, 1542 is a starred
year, marked by a revolution in our knowledge alike of Macrocosm and
Microcosm. In Frauenburg, the town physician and a canon, now nearing
the Psalmist limit and his end, had sent to the press the studies of a
lifetime--"De revolutionibus orbium coelestium." It was no new thought,
no new demonstration that Copernicus thus gave to his generation.
Centuries before, men of the keenest scientific minds from Pythagoras on
had worked out a heliocentric theory, fully promulgated by Aristarchus,
and very generally accepted by the brilliant investigators of the
Alexandrian school; but in the long interval, lapped in Oriental
lethargy, man had been content to acknowledge that the heavens declare
the glory of God and that the firmament sheweth his handiwork. There
had been great astronomers before Copernicus. In the fifteenth century
Nicholas of Cusa and Regiomontanus had hinted at the heliocentric
theory; but 1512 marks an epoch in the history of science, since for all
time Copernicus put the problem in a way that compelled acquiescence.

Nor did Copernicus announce a truth perfect and complete, not to be
modified, but there were many contradictions and lacunae which the work
of subsequent observers had to reconcile and fill up. For long years
Copernicus had brooded over the great thoughts which his careful
observation had compelled. We can imagine the touching scene in the
little town when his friend Osiander brought the first copy of the
precious volume hot from the press, a well enough printed book. Already
on his deathbed, stricken with a long illness, the old man must have had
doubts how his work would be received, though years before Pope Clement
VII had sent him encouraging words. Fortunately death saved him from the
"rending" which is the portion of so many innovators and discoverers.
His great contemporary reformer, Luther, expressed the view of the day
when he said the fool will turn topsy-turvy the whole art of astronomy;
but the Bible says that Joshua commanded the Sun to stand still, not
the Earth. The scholarly Melanchthon, himself an astronomer, thought
the book so godless that he recommended its suppression (Dannemann,
Grundriss). The church was too much involved in the Ptolemaic system to
accept any change and it was not until 1822 that the works of Copernicus
were removed from the Index.

VESALIUS

THE same year, 1542, saw a very different picture in the far-famed city
of Padua, "nursery of the arts." The central figure was a man not yet in
the prime of life, and justly full of its pride, as you may see from
his portrait. Like Aristotle and Hippocrates cradled and nurtured in an
AEsculapian family, Vesalius was from his childhood a student of nature,
and was now a wandering scholar, far from his Belgian home. But in Italy
he had found what neither Louvain nor Paris could give, freedom in
his studies and golden opportunities for research in anatomy. What an
impression he must have made on the student body at Padua may be judged
from the fact that shortly after his graduation in December, 1537,
at the age of twenty-four, he was elected to the chair of anatomy and
surgery. Two things favored him--an insatiate desire to see and handle
for himself the parts of the human frame, and an opportunity, such as
had never before been offered to the teacher, to obtain material for the
study of human anatomy. Learned with all the learning of the Grecians
and of the Arabians, Vesalius grasped, as no modern before him had done,
the cardinal fact that to know the human machine and its working, it is
necessary first to know its parts--its fabric.

To appreciate the work of this great man we must go back in a brief
review of the growth of the study of anatomy.

Among the Greeks only the Alexandrians knew human anatomy. What their
knowledge was we know at second hand, but the evidence is plain that
they knew a great deal. Galen's anatomy was first-class and was based
on the Alexandrians and on his studies of the ape and the pig. We have
already noted how much superior was his osteology to that of Mundinus.
Between the Alexandrians and the early days of the School of Salernum we
have no record of systematic dissections of the human body. It is even
doubtful if these were permitted at Salernum. Neuburger states that the
instructions of Frederick II as to dissections were merely nominal.

How atrocious was the anatomy of the early Middle Ages may be gathered
from the cuts in the works of Henri de Mondeville. In the Bodleian
Library is a remarkable Latin anatomical treatise of the late thirteenth
century, of English provenance, one illustration from which will suffice
to show the ignorance of the author. Mundinus of Bologna, one of the
first men in the Middle Ages to study anatomy from the subject, was
under the strong domination of the Arabians, from whom he appears to
have received a very imperfect Galenic anatomy. From this date we meet
with occasional dissections at various schools, but we have seen that in
the elaborate curriculum of the University of Padua in the middle of the
fifteenth century there was no provision for the study of the subject.
Even well into the sixteenth century dissections were not common, and
the old practice was followed of holding a professorial discourse,
while the butcher, or barber surgeon, opened the cavities of the body. A
member of a famous Basel family of physicians, Felix Plater, has left
us in his autobiography(19) details of the dissections he witnessed at
Montpellier between November 14, 1552, and January 10, 1557, only eleven
in number. How difficult it was at that time to get subjects is shown by
the risks they ran in "body-snatching" expeditions, of which he records
three.

     (19) There is no work from which we can get a better idea of the
     life of the sixteenth-century medical student and of the style of
     education and of the degree ceremonies, etc.  Cumston has given
     an excellent summary of it (Johns Hopkins Hospital Bulletin,
     1912, XXIII, 105-113).

And now came the real maker of modern anatomy. Andreas Vesalius had a
good start in life. Of a family long associated with the profession,
his father occupied the position of apothecary to Charles V, whom he
accompanied on his journeys and campaigns. Trained at Louvain, he had,
from his earliest youth, an ardent desire to dissect, and cut up mice
and rats, and even cats and dogs. To Paris, the strong school of the
period, he went in 1533, and studied under two men of great renown,
Jacob Sylvius and Guinterius. Both were strong Galenists and regarded
the Master as an infallible authority. He had as a fellow prosector,
under the latter, the unfortunate Servetus. The story of his troubles
and trials in getting bones and subjects you may read in Roth's
"Life."(20) Many interesting biographical details are also to be found
in his own writings. He returned for a time to Louvain, and here he
published his first book, a commentary on the "Almansor" of Rhazes, in
1537.

     (20) M. Roth:  Andreas Vesalius Bruxellensis, Berlin, 1892. An
     excellent account of Vesalius and his contemporaries is given by
     James Moores Ball in his superbly printed Andreas Vesalius, the
     Reformer of Anatomy, St. Louis, 1910.

Finding it difficult, either in Paris or Louvain, to pursue his
anatomical studies, he decided to go to Italy where, at Venice and
Padua, the opportunities were greater. At Venice, he attended the
practice of a hospital (now a barracks) which was in charge of the
Theatiner Order. I show you a photograph of the building taken last
year. And here a strange destiny brought two men together. In 1537,
another pilgrim was working in Venice waiting to be joined by his six
disciples. After long years of probation, Ignatius Loyola was ready to
start on the conquest of a very different world. Devoted to the sick
and to the poor, he attached himself to the Theatiner Order, and in the
wards of the hospital and the quadrangle, the fiery, dark-eyed, little
Basque must frequently have come into contact with the sturdy young
Belgian, busy with his clinical studies and his anatomy. Both were to
achieve phenomenal success--the one in a few years to revolutionize
anatomy, the other within twenty years to be the controller of
universities, the counsellor of kings, and the founder of the most
famous order in the Roman Catholic Church. It was in this hospital that
Vesalius made observations on the China-root, on which he published a
monograph in 1546. The Paduan School was close to Venice and associated
with it, so that the young student had probably many opportunities of
going to and fro. On the sixth of December, 1537, before he had reached
his twenty-fourth year and shortly after taking his degree, he was
elected to the chair of surgery and anatomy at Padua.

The task Vesalius set himself to accomplish was to give an accurate
description of all the parts of the human body, with proper
illustrations. He must have had abundant material, more, probably, than
any teacher before him had ever had at his disposal. We do not know
where he conducted his dissections, as the old amphitheatre has
disappeared, but it must have been very different from the tiny one
put up by his successor, Fabricius, in 1594. Possibly it was only a
temporary building, for he says in the second edition of the "Fabrica"
that he had a splendid lecture theatre which accommodated more than five
hundred spectators (p. 681).

With Vesalius disappeared the old didactic method of teaching anatomy.
He did his own dissections, made his own preparations, and, when human
subjects were scarce, employed dogs, pigs or cats, and occasionally a
monkey. For five years he taught and worked at Padua. He is known
to have given public demonstrations in Bologna and elsewhere. In the
"China-root" he remarks that he once taught in three universities in one
year. The first fruit of his work is of great importance in connection
with the evolution of his knowledge. In 1538, he published six
anatomical tables issued apparently in single leaves. Of the famous
"Tabulae Anatomicae" only two copies are known, one in the San
Marco Library, Venice, and the other in the possession of Sir John
Stirling-Maxwell, whose father had it reproduced in facsimile (thirty
copies only) in 1874. Some of the figures were drawn by Vesalius
himself, and some are from the pencil of his friend and countryman,
Stephan van Calcar. Those plates were extensively pirated. About this
time he also edited for the Giunti some of the anatomical works of
Galen.(21)

     (21) De anatomicis administrationibus, De venarum arterinrumque
     dissectione, included in the various Juntine editions of Galen.

We know very little of his private life at Padua. His most important
colleague in the faculty was the famous Montanus, professor of medicine.
Among his students and associates was the Englishman Caius, who lived in
the same house with him. When the output is considered, he cannot have
had much spare time at Padua.

He did not create human anatomy--that had been done by the
Alexandrians--but he studied it in so orderly and thorough a manner
that for the first time in history it could be presented in a way that
explained the entire structure of the human body. Early in 1542 the MS.
was ready; the drawings had been made with infinite care, the blocks for
the figures had been cut, and in September, he wrote to Oporinus urging
that the greatest pains should be taken with the book, that the paper
should be strong and of equal thickness, the workmen chosen for their
skill, and that every detail of the pictures must be distinctly visible.
He writes with the confidence of a man who realized the significance of
the work he had done. It is difficult to speak in terms of moderation of
the "Fabrica." To appreciate its relative value one must compare it with
the other anatomical works of the period, and for this purpose I
put before you two figures from a text-book on the subject that was
available for students during the first half of the sixteenth century.
In the figures and text of the "Fabrica" we have anatomy as we know it;
and let us be honest and say, too, largely as Galen knew it. Time will
not allow me to go into the question of the relations of these two
great anatomists, but we must remember that at this period Galen ruled
supreme, and was regarded in the schools as infallible. And now, after
five years of incessant labor, Vesalius was prepared to leave his
much loved Padua and his devoted students. He had accomplished an
extraordinary work. He knew, I feel sure, what he had done. He knew that
the MSS. contained something that the world had not seen since the great
Pergamenian sent the rolls of his "Manual of Anatomy" among his friends.
Too precious to entrust to any printer but the best--and the best in the
middle of the sixteenth century was Transalpine--he was preparing to go
north with the precious burden. We can picture the youthful teacher--he
was but twenty-eight--among students in a university which they
themselves controlled--some of them perhaps the very men who five years
before had elected him--at the last meeting with his class, perhaps
giving a final demonstration of the woodcuts, which were of an accuracy
and beauty never seen before by students' eyes, and reading his
introduction. There would be sad hearts at the parting, for never had
anyone taught anatomy as he had taught it--no one had ever known anatomy
as he knew it. But the strong, confident look was on his face and with
the courage of youth and sure of the future, he would picture a happy
return to attack new and untried problems. Little did he dream that his
happy days as student and teacher were finished, that his work as an
anatomist was over, that the most brilliant and epoch-making part of his
career as a professor was a thing of the past. A year or more was spent
at Basel with his friend Oporinus supervising the printing of the
great work, which appeared in 1543 with the title "De Humani Corporis
Fabrica." The worth of a book, as of a man, must be judged by results,
and, so judged, the "Fabrica" is one of the great books of the world,
and would come in any century of volumes which embraced the richest
harvest of the human mind. In medicine, it represents the full flower
of the Renaissance. As a book it is a sumptuous tome a worthy setting
of his jewel--paper, type and illustration to match, as you may see for
yourselves in this folio--the chef d'oeuvre of any medical library.

In every section, Vesalius enlarged and corrected the work of Galen.
Into the details we need not enter: they are all given in Roth's
monograph, and it is a chapter of ancient history not specially
illuminating.

Never did a great piece of literary work have a better setting. Vesalius
must have had a keen appreciation of the artistic side of the art of
printing, and he must also have realized the fact that the masters of
the art had by this time moved north of the Alps.

While superintending the printing of the precious work in the winter of
1542-1543 in Basel, Vesalius prepared for the medical school a skeleton
from the body of an executed man, which is probably the earliest
preparation of the kind in Europe. How little anatomy had been studied
at the period may be judged from that fact that there had been
no dissection at Basel since 1531.(22) The specimen is now in the
Vesalianum, Basel, of which I show you a picture taken by Dr. Harvey
Cushing. From the typographical standpoint no more superb volume
on anatomy has been issued from any press, except indeed the second
edition, issued in 1555. The paper is, as Vesalius directed, strong and
good, but it is not, as he asked, always of equal thickness; as a rule
it is thick and heavy, but there are copies on a good paper of a much
lighter quality. The illustrations drawn by his friend and fellow
countryman, van Calcar, are very much in advance of anything previously
seen, except those of Leonardo. The title-page, one of the most
celebrated pictures in the history of medicine, shows Vesalius in
a large amphitheatre (an imaginary one of the artist, I am afraid)
dissecting a female subject. He is demonstrating the abdomen to a group
of students about the table, but standing in the auditorium are elderly
citizens and even women. One student is reading from an open book. There
is a monkey on one side of the picture and a dog on the other. Above
the picture on a shield are the three weasels, the arms of Vesal. The
reproduction which I show you here is from the "Epitome"--a smaller work
issued before (?) the "Fabrica," with rather larger plates, two of which
represent nude human bodies and are not reproduced in the great work.
The freshest and most beautiful copy is the one on vellum which formerly
belonged to Dr. Mead, now in the British Museum, and from it this
picture was taken. One of the most interesting features of the book are
the full-page illustrations of the anatomy of the arteries, veins
and nerves. They had not in those days the art of making corrosion
preparations, but they could in some way dissect to their finest
ramifications the arteries, veins and nerves, which were then spread on
boards and dried. Several such preparations are now at the College of
Physicians in London, brought from Padua by Harvey. The plates of the
muscles are remarkably good, more correct, though not better perhaps, on
the whole, than some of Leonardo's.

     (22) The next, in 1559, is recorded by Plater in his
     autobiography, who gave a public dissection during three days in
     the Church of St. Elizabeth.

Vesalius had no idea of a general circulation. Though he had escaped
from the domination of the great Pergamenian in anatomy, he was still
his follower in physiology. The two figures annexed, taken from one
of the two existing copies of the "Tabulae Anatomica," are unique in
anatomical illustration, and are of special value as illustrating the
notion of the vascular system that prevailed until Harvey's day. I
have already called your attention to Galen's view of the two separate
systems, one containing the coarse, venous blood for the general
nutrition of the body, the other the arterial, full of a thinner, warmer
blood with which were distributed the vital spirits and the vital
heat. The veins had their origin in the liver; the superior vena cava
communicated with the right heart, and, as Galen taught, some blood was
distributed to the lungs; but the two systems were closed, though Galen
believed there was a communication at the periphery between the
arteries and veins. Vesalius accepted Galen's view that there is some
communication between the venous and arterial systems through pores
in the septum of the ventricles, though he had his doubts, and in the
second edition of his book (1555) says that inspite of the authority
of the Prince of Physicians he cannot see how the smallest quantity of
blood could be transmitted through so dense a muscular septum. Two years
before this (1553),(*) his old fellow student, Michael Servetus, had in
his "Christianismi Restitutio" annatomical touch with one another!

     (*) See the Servetus Notes in the Osler Anniversary Volumes, New
     York, 1919, Vol. II.--Ed.

The publication of the "Fabrica" shook the medical world to its
foundations. Galen ruled supreme in the schools: to doubt him in the
least particular roused the same kind of feeling as did doubts on the
verbal inspiration of the Scriptures fifty years ago! His old teachers
in Paris were up in arms: Sylvius, nostrae aetatis medicorum decus, as
Vesalius calls him, wrote furious letters, and later spoke of him as
a madman (vaesanus). The younger men were with him and he had many
friends, but he had aroused a roaring tide of detraction against which
he protested a few years later in his work on the "China-root," which
is full of details about the "Fabrica." In a fit of temper he threw
his notes on Galen and other MSS. in the fire. No sadder page exists in
medical writings than the one in which Vesalius tells of the burning of
his books and MSS. It is here reproduced and translated.(23) His life
for a couple of years is not easy to follow, but we know that in 1546
he took service with Charles V as his body physician, and the greatest
anatomist of his age was lost in the wanderings of court and campaigns.
He became an active practitioner, a distinguished surgeon, much
consulted by his colleagues, and there are references to many of his
cases, the most important of which are to internal aneurysms, which he
was one of the first to recognize. In 1555 he brought out the second
edition of the "Fabrica," an even more sumptuous volume than the first.

     (23) Epistle on China-root, 1546, p. 196.  Vesalius may be quoted
     in explanation--in palliation:

"All these impediments I made light of; for I was too young to seek
gain by my art, and I was sustained by my eager desire to learn and to
promote the studies in which I shared. I say nothing of my diligence in
anatomizing--those who attended my lectures in Italy know how I spent
three whole weeks over a single public dissection. But consider that in
one year I once taught in three different universities. If I had put
off the task of writing till this time; if I were now just beginning
to digest my materials; students would not have had the use of my
anatomical labours, which posterity may or may not judge superior to
the rechauffes formerly in use, whether of Mesua, of Gatinaria, of some
Stephanus or other on the differences, causes and symptoms of diseases,
or, lastly, of a part of Servitor's pharmacopoeia. As to my notes, which
had grown into a huge volume, they were all destroyed by me; and on the
same day there similarly perished the whole of my paraphrase on the ten
books of Rhazes to King Almansor, which had been composed by me with far
more care than the one which is prefaced to the ninth book. With
these also went the books of some author or other on the formulae and
preparation of medicines, to which I had added much matter of my own
which I judged to be not without utility; and the same fate overtook all
the books of Galen which I had used in learning anatomy, and which I had
liberally disfigured in the usual fashion. I was on the point of leaving
Italy and going to Court; those physicians you know of had made to the
Emperor and to the nobles a most unfavourable report of my books and of
all that is published nowadays for the promotion of study; I therefore
burnt all these works that I have mentioned, thinking at the same time
that it would be an easy matter to abstain from writing for the future.
I must show that I have since repented more than once of my impatience,
and regretted that I did not take the advice of the friends who were
then with me."

There is no such pathetic tragedy in the history of our profession.
Before the age of thirty Vesalius had effected a revolution in anatomy;
he became the valued physician of the greatest court of Europe; but call
no man happy till he is dead! A mystery surrounds his last days. The
story is that he had obtained permission to perform a post-mortem
examination on the body of a young Spanish nobleman, whom he had
attended. When the body was opened, the spectators to their horror saw
the heart beating, and there were signs of life! Accused, so it is said,
by the Inquisition of murder and also of general impiety he only escaped
through the intervention of the King, with the condition that he make a
pilgrimage to the Holy Land. In carrying this out in 1564 he was wrecked
on the island of Zante, where he died of a fever or of exhaustion, in
the fiftieth year of his age.

To the North American Review, November, 1902, Edith Wharton contributed
a poem on "Vesalius in Zante," in which she pictures his life, so
full of accomplishment, so full of regrets--regrets accentuated by the
receipt of an anatomical treatise by Fallopius, the successor to the
chair in Padua! She makes him say:

     There are two ways of spreading light; to be
     The candle or the mirror that reflects it.
     I let my wick burn out--there yet remains
     To spread an answering surface to the flame
     That others kindle.

But between Mundinus and Vesalius, anatomy had been studied by a group
of men to whom I must, in passing, pay a tribute. The great artists
Raphael, Michael Angelo and Albrecht Durer were keen students of the
human form. There is an anatomical sketch by Michael Angelo in the
Ashmolean Museum, Oxford, which I here reproduce.(*) Durer's famous work
on "Human Proportion," published in 1528, contains excellent figures,
but no sketches of dissections. But greater than any of these, and
antedating them, is Leonardo da Vinci, the one universal genius in
whom the new spirit was incarnate--the Moses who alone among his
contemporaries saw the promised land. How far Leonardo was indebted to
his friend and fellow student, della Torre, at Pavia we do not know,
nor does it matter in face of the indubitable fact that in the
many anatomical sketches from his hand we have the first accurate
representation of the structure of the body. Glance at the three figures
of the spine which I have had photographed side by side, one from
Leonardo, one from Vesalius and the other from Vandyke Carter, who did
the drawings in Gray's "Anatomy" (1st ed., 1856). They are all of the
same type, scientific, anatomical drawings, and that of Leonardo was
done fifty years before Vesalius! Compare, too, this figure of the
bones of the foot with a similar one from Vesalius.(24) Insatiate
in experiment, intellectually as greedy as Aristotle, painter, poet,
sculptor, engineer, architect, mathematician, chemist, botanist,
aeronaut, musician and withal a dreamer and mystic, full accomplishment
in any one department was not for him! A passionate desire for a mastery
of nature's secrets made him a fierce thing, replete with too much
rage! But for us a record remains--Leonardo was the first of modern
anatomists, and fifty years later, into the breach he made, Vesalius
entered.(25)

     (*) This plate was lacking among the author's illustrations, but
     the Keeper of the Ashmolean Museum remembers his repeatedly
     showing special interest in the sketch reproduced in John
     Addington Symonds's Life of Michelangelo, London, 1893, Vol. I,
     p. 44, and in Charles Singer's Studies in the History and Method
     of Science, Oxford, 1917, Vol. I, p. 97, representing Michael
     Angelo and a friend dissecting the body of a man, by the light of
     a candle fixed in the body itself.--Ed.

     (24) He was the first to make and represent anatomical cross
     sections. See Leonardo:  Quaderni d'Anatomia, Jacob Dybwad,
     Kristiania, 1911-1916, Vol. V.

     (25) See Knox:  Great Artists and Great Anatomists, London, 1862,
     and Mathias Duval in Les Manuserits de Leonard de Vince: De
     l'Anatomie, Feuillets A, Edouard Rouveyre, Paris, 1898. For a
     good account of Leonardo da Vinci see Merejkovsky's novel, The
     Forerunner, London, 1902, also New York, Putnam.

HARVEY

LET us return to Padua about the year 1600. Vesalius, who made the
school the most famous anatomical centre in Europe, was succeeded by
Fallopius, one of the best-known names in anatomy, at whose death an
unsuccessful attempt was made to get Vesalius back. He was succeeded in
1565 by a remarkable man, Fabricius (who usually bears the added name
of Aquapendente, from the town of his birth), a worthy follower of
Vesalius. In 1594, in the thirtieth year of his professoriate, he built
at his own expense a new anatomical amphitheatre, which still exists
in the university buildings. It is a small, high-pitched room with six
standing-rows for auditors rising abruptly one above the other. The
arena is not much more than large enough for the dissecting table which,
by a lift, could be brought up from a preparing room below. The study of
anatomy at Padua must have declined since the days of Vesalius if this
tiny amphitheatre held all its students; none the less, it is probably
the oldest existing anatomical lecture room, and for us it has a very
special significance.

Early in his anatomical studies Fabricius had demonstrated the valves in
the veins. I show you here two figures, the first, as far as I know, in
which these structures are depicted. It does not concern us who first
discovered them; they had doubtless been seen before, but Fabricius
first recognized them as general structures in the venous system, and he
called them little doors--"ostiola."

The quadrangle of the university building at Padua is surrounded by
beautiful arcades, the walls and ceilings of which are everywhere
covered with the stemmata, or shields, of former students, many of them
brilliantly painted. Standing in the arcade on the side of the "quad"
opposite the entrance, if one looks on the ceiling immediately above the
capital of the second column to the left there is seen the stemma which
appears as tailpiece to this chapter, put up by a young Englishman,
William Harvey, who had been a student at Padua for four years. He
belonged to the "Natio Anglica," of which he was Conciliarius, and
took his degree in 1602. Doubtless he had repeatedly seen Fabricius
demonstrate the valves of the veins, and he may indeed, as a senior
student, have helped in making the very dissections from which the
drawings were taken for Fabricius' work, "De Venarum Osteolis," 1603.
If one may judge from the character of the teacher's work the sort of
instruction the student receives, Harvey must have had splendid training
in anatomy. While he was at Padua, the great work of Fabricius, "De
Visione, Voce et Auditu" (1600) was published, then the "Tractatus de
Oculo Visusque Organo" (1601), and in the last year of his residence
Fabricius must have been busy with his studies on the valves of the
veins and with his embryology, which appeared in 1604. Late in life,
Harvey told Boyle that it was the position of the valves of the veins
that induced him to think of a circulation.

Harvey returned to England trained by the best anatomist of his day. In
London, he became attached to the College of Physicans, and taking his
degree at Cambridge, he began the practice of medicine. He was elected
a fellow of the college in 1607 and physician to St. Bartholomew's
Hospital in 1609. In 1615 he was appointed Lumleian lecturer to the
College of Physicians, and his duties were to hold certain "public
anatomies," as they were called, or lectures. We know little or nothing
of what Harvey had been doing other than his routine work in the care
of the patients at St. Bartholomew's. It was not until April, 1616, that
his lectures began. Chance has preserved to us the notes of this first
course; the MS. is now in the British Museum and was published in
facsimile by the college in 1886.(26)

     (26) William Harvey:  Prelectiones Anatomiae Universalis, London,
     J. & A. Churchill, 1886.

The second day lecture, April 17, was concerned with a description of
the organs of the thorax, and after a discussion on the structure and
action of the heart come the lines:

     W. H. constat per fabricam cordis sanguinem
     per pulmones in Aortam perpetuo
     transferri, as by two clacks of a
     water bellows to rayse water
     constat per ligaturam transitum sanguinis
     ab arteriis ad venas
     unde perpetuum sanguinis motum
     in circulo fieri pulsu cordis.

The illustration will give one an idea of the extraordinarily crabbed
hand in which the notes are written, but it is worth while to see the
original, for here is the first occasion upon which is laid down in
clear and unequivocal words that the blood CIRCULATES. The lecture gave
evidence of a skilled anatomist, well versed in the literature from
Aristotle to Fabricius. In the MS. of the thorax, or, as he calls it,
the "parlour" lecture, there are about a hundred references to some
twenty authors. The remarkable thing is that although those lectures
were repeated year by year, we have no evidence that they made any
impression upon Harvey's contemporaries, so far, at least, as to excite
discussions that led to publication. It was not until twelve years
later, 1628, that Harvey published in Frankfurt a small quarto volume
of seventy-four pages,(27) "De Motu Cordis." In comparison with the
sumptuous "Fabrica" of Vesalius this is a trifling booklet; but if not
its equal in bulk or typographical beauty (it is in fact very poorly
printed), it is its counterpart in physiology, and did for that science
what Vesalius had done for anatomy, though not in the same way. The
experimental spirit was abroad in the land, and as a student at Padua,
Harvey must have had many opportunities of learning the technique of
vivisection; but no one before his day had attempted an elaborate piece
of experimental work deliberately planned to solve a problem relating to
the most important single function of the body. Herein lies the special
merit of his work, from every page of which there breathes the modern
spirit. To him, as to Vesalius before him, the current views of the
movements of the blood were unsatisfactory, more particularly the
movements of the heart and arteries, which were regarded as an active
expansion by which they were filled with blood, like bellows with air.
The question of the transmission of blood through the thick septum
and the transference of air and blood from the lungs to the heart were
secrets which he was desirous of searching out by means of experiment.

     (27) Harvey:  Exercitatio Anatomica de Motu Cordis et Sanguinis
     in Animalibus, Francofurti, 1628.

One or two special points in the work may be referred to as illustrating
his method. He undertook first the movements of the heart, a task so
truly arduous and so full of difficulties that he was almost tempted to
think with Fracastorius that "the movement of the heart was only to be
comprehended by God." But after many difficulties he made the following
statements: first, that the heart is erected and raises itself up into
an apex, and at this time strikes against the breast and the pulse is
felt externally; secondly, that it is contracted every-way, but more
so at the sides; and thirdly, that grasped in the hand it was felt
to become harder at the time of its motion; from all of which actions
Harvey drew the very natural conclusion that the activity of the heart
consisted in a contraction of its fibres by which it expelled the blood
from the ventricles. These were the first four fundamental facts which
really opened the way for the discovery of the circulation, as it did
away with the belief that the heart in its motion attracts blood into
the ventricles, stating on the contrary that by its contraction it
expelled the blood and only received it during its period of repose or
relaxation. Then he proceeded to study the action of the arteries and
showed that their period of diastole, or expansion, corresponded with
the systole, or contraction, of the heart, and that the arterial pulse
follows the force, frequency and rhythm of the ventricle and is, in
fact, dependent upon it. Here was another new fact: that the pulsation
in the arteries was nothing else than the impulse of the blood within
them. Chapter IV, in which he describes the movements of the auricles
and ventricles, is a model of accurate description, to which little has
since been added. It is interesting to note that he mentions what is
probably auricular fibrillation. He says: "After the heart had ceased
pulsating an undulation or palpitation remained in the blood itself
which was contained in the right auricle, this being observed so long as
it was imbued with heat and spirit." He recognized too the importance of
the auricles as the first to move and the last to die. The accuracy and
vividness of Harvey's description of the motion of the heart have been
appreciated by generations of physiologists. Having grasped this first
essential fact, that the heart was an organ for the propulsion of blood,
he takes up in Chapters VI and VII the question of the conveyance of the
blood from the right side of the heart to the left. Galen had already
insisted that some blood passed from the right ventricle to the
lungs--enough for their nutrition; but Harvey points out, with Colombo,
that from the arrangement of the valves there could be no other view
than that with each impulse of the heart blood passes from the right
ventricle to the lungs and so to the left side of the heart. How
it passed through the lungs was a problem: probably by a continuous
transudation. In Chapters VIII and IX he deals with the amount of blood
passing through the heart from the veins to the arteries. Let me quote
here what he says, as it is of cardinal import:

"But what remains to be said upon the quantity and source of the blood
which thus passes, is of a character so novel and unheard of that I not
only fear injury to myself from the envy of a few, but I tremble lest
I have mankind at large for my enemies, so much doth wont and custom
become a second nature. Doctrine once sown strikes deeply its root, and
respect for antiquity influences all men. Still the die is cast, and my
trust is in my love of truth, and the candour of cultivated minds."(28)
Then he goes on to say:

     (28) William Harvey:  Exercitatio Anatomica de Motu Cordis et
     Sanguinis in Animalibus, Francofurti, 1628, G. Moreton's
     facsimile reprint and translation, Canterbury, 1894, p. 48.

"I began to think whether there might not be A MOVEMENT, AS IT WERE, IN
A CIRCLE. Now this I afterwards found to be true; and I finally saw that
the blood, forced by the action of the left ventricle into the arteries,
was distributed to the body at large, and its several parts, in the same
manner as it is sent through the lungs, impelled by the right ventricle
into the pulmonary artery, and that it then passed through the veins and
along the vena cava, and so round to the left ventricle in the manner
already indicated."(29)

     (29) Ibid. p. 49.

The experiments dealing with the transmission of blood in the veins
are very accurate, and he uses the old experiment that Fabricius had
employed to show the valves, to demonstrate that the blood in the veins
flows towards the heart. For the first time a proper explanation of the
action of the valves is given. Harvey had no appreciation of how
the arteries and veins communicated with each other. Galen, you may
remember, recognized that there were anastomoses, but Harvey preferred
the idea of filtration.

The "De Motu Cordis" constitutes a unique piece of work in the history
of medicine. Nothing of the same type had appeared before. It is
a thoroughly sensible, scientific study of a definite problem, the
solution of which was arrived at through the combination of accurate
observation and ingenious experiment. Much misunderstanding has arisen
in connection with Harvey's discovery of the circulation of the blood.
He did not discover that the blood moved,--that was known to Aristotle
and to Galen, from both of whom I have given quotations which indicate
clearly that they knew of its movement,--but at the time of Harvey not a
single anatomist had escaped from the domination of Galen's views.
Both Servetus and Colombo knew of the pulmonary circulation, which was
described by the former in very accurate terms. Cesalpinus, a great
name in anatomy and botany, for whom is claimed the discovery of the
circulation, only expressed the accepted doctrines in the following
oft-quoted phrase:

"We will now consider how the attraction of aliment and the process
of nutrition takes place in plants; for in animals we see the aliment
brought through the veins to the heart, as to a laboratory of innate
heat, and, after receiving there its final perfection, distributed
through the arteries to the body at large, by the agency of the spirits
produced from this same aliment in the heart."(30) There is nothing
in this but Galen's view, and Cesalpinus believed, as did all his
contemporaries, that the blood was distributed through the body by the
vena cava and its branches for the nourishment of all its parts.(*) To
those who have any doubts as to Harvey's position in this matter I would
recommend the reading of the "De Motu Cordis" itself, then the various
passages relating to the circulation from Aristotle to Vesalius. Many
of these can be found in the admirable works of Dalton, Flourens,
Richet and Curtis.(31) In my Harveian Oration for 1906(32) I have dealt
specially with the reception of the new views, and have shown how long
it was before the reverence for Galen allowed of their acceptance. The
University of Paris opposed the circulation of the blood for more than
half a century after the appearance of the "De Motu Cordis."

     (30) De Plantis, Lib I, cap. 2.

     (*) Cesalpinus has also a definite statement of the circlewise
     process.--Ed.

     (31) J. C. Dalton Doctrines of the Circulation, Philadelphia,
     1884; Flourens Histoire de la decouverte de la circulation du
     sang, 2d ed., Paris, 1857; Charles Richet Harvey, la circulation
     du sang, Paris, 1879; John G. Curtis Harvey's views on the use of
     Circulation, etc., New York, 1916.

     (32) Osler An Alabama Student and Other Biographical Essays,
     Oxford, 1908, p. 295.

To summarize--until the seventeenth century there were believed to
be two closed systems in the circulation, (1) the natural, containing
venous blood, had its origin in the liver from which, as from a
fountain, the blood continually ebbed and flowed for the nourishment of
the body; (2) the vital, containing another blood and the spirits, ebbed
and flowed from the heart, distributing heat and life to all parts. Like
a bellows the lungs fanned and cooled this vital blood. Here and there
we find glimmering conceptions of a communication between these systems,
but practically all teachers believed that the only one of importance
was through small pores in the wall separating the two sides of the
heart. Observation--merely looking at and thinking about things--had
done all that was possible, and further progress had to await the
introduction of a new method, viz., experiment. Galen, it is true, had
used this means to show that the arteries of the body contained blood
and not air. The day had come when men were no longer content with
accurate description and with finely spun theories and dreams. It was
reserved for the immortal Harvey to put into practice the experimental
method by which he demonstrated conclusively that the blood moved in a
circle. The "De Motu Cordis" marks the final break of the modern spirit
with the old traditions. It took long for men to realize the value of
this "inventum mirabile" used so effectively by the Alexandrians--by
Galen--indeed, its full value has only been appreciated within the past
century. Let me quote a paragraph from my Harveian Oration.(33) "To the
age of the hearer, in which men had heard and heard only, had succeeded
the age of the eye in which men had seen and had been content only
to see. But at last came the age of the hand--the thinking, devising,
planning hand, the hand as an instrument of the mind, now re-introduced
into the world in a modest little monograph from which we may date the
beginning of experimental medicine."

     (33) Osler:  An Alabama Student, etc., pp. 329-330.

Harvey caught the experimental spirit in Italy, with brain, eye and hand
as his only aids, but now an era opened in which medicine was to derive
an enormous impetus from the discovery of instruments of precision. "The
new period in the development of the natural sciences, which reached
its height in the work of such men as Galileo, Gilbert and Kepler, is
chiefly characterized by the invention of very important instruments for
aiding and intensifying the perceptions of the senses, by means of which
was gained a much deeper insight into the phenomena than had hitherto
been possible. Such instruments as the earlier ages possessed were
little more than primitive hand-made tools. Now we find a considerable
number of scientifically made instruments deliberately planned for
purposes of special research, and as it were, on the threshold of the
period stand two of the most important, the compound microscope and
the telescope. The former was invented about 1590 and the latter about
1608."(34) It was a fellow professor of the great genius Galileo who
attempted to put into practice the experimental science of his friend.
With Sanctorius began the studies of temperature, respiration and the
physics of the circulation. The memory of this great investigator has
not been helped by the English edition of his "De Statica Medicina," not
his best work, with a frontispiece showing the author in his dietetic
balance. Full justice has been done to him by Dr. Weir Mitchell in
an address as president of the Congress of Physicians and Surgeons,
1891.(35) Sanctorius worked with a pulsilogue devised for him by
Galileo, with which he made observations on the pulse. He is said
to have been the first to put in use the clinical thermometer. His
experiments on insensible perspiration mark him as one of the first
modern physiologists.

     (34) Dannemann:  Die Naturwissenschaften in ihrer
     Entwickelung..., Vol. II, p. 7, Leipzig, 1911.

     (35) See Transactions Congress Physicians and Surgeons, 1891, New
     Haven, 1892, II, 159-181.

But neither Sanctorius nor Harvey had the immediate influence upon their
contemporaries which the novel and stimulating character of their work
justified. Harvey's great contemporary, Bacon, although he lost his
life in making a cold storage experiment, did not really appreciate the
enormous importance of experimental science. He looked very coldly upon
Harvey's work. It was a philosopher of another kidney, Rene Descartes,
who did more than anyone else to help men to realize the value of the
better way which Harvey had pointed out. That the beginning of wisdom
was in doubt, not in authority, was a novel doctrine in the world,
but Descartes was no armchair philosopher, and his strong advocacy and
practice of experimentation had a profound influence in directing men to
"la nouvelle methode." He brought the human body, the earthly machine,
as he calls it, into the sphere of mechanics and physics, and he wrote
the first text-book of physiology, "De l'Homme." Locke, too, became the
spokesman of the new questioning spirit, and before the close of the
seventeenth century, experimental research became all the mode. Richard
Lower, Hooke and Hales were probably more influenced by Descartes
than by Harvey, and they made notable contributions to experimental
physiology in England. Borelli, author of the famous work on "The Motion
of Animals" (Rome, 1680-1681), brought to the study of the action of
muscles a profound knowledge of physics and mathematics and really
founded the mechanical, or iatromechanical school. The literature and
the language of medicine became that of physics and mechanics: wheels
and pulleys, wedges, levers, screws, cords, canals, cisterns, sieves and
strainers, with angles, cylinders, celerity, percussion and resistance,
were among the words that now came into use in medical literature.
Withington quotes a good example in a description by Pitcairne, the Scot
who was professor of medicine at Leyden at the end of the seventeenth
century. "Life is the circulation of the blood. Health is its free and
painless circulation. Disease is an abnormal motion of the blood, either
general or local. Like the English school generally, he is far more
exclusively mechanical than are the Italians, and will hear nothing of
ferments or acids, even in digestion. This, he declares, is a purely
mechanical process due to heat and pressure, the wonderful effects of
which may be seen in Papin's recently invented 'digester.' That the
stomach is fully able to comminute the food may be proved by the
following calculation. Borelli estimates the power of the flexors of the
thumb at 3720 pounds, their average weight being 122 grains. Now, the
average weight of the stomach is eight ounces, therefore it can develop
a force of 117,088 pounds, and this may be further assisted by the
diaphragm and abdominal muscles the power of which, estimated in the
same way, equals 461,219 pounds! Well may Pitcairne add that this
force is not inferior to that of any millstone."(36) Paracelsus gave an
extraordinary stimulus to the study of chemistry and more than anyone
else he put the old alchemy on modern lines. I have already quoted his
sane remark that its chief service is in seeking remedies. But there is
another side to this question. If, as seems fairly certain, the Basil
Valentine whose writings were supposed to have inspired Paracelsus was
a hoax and his works were made up in great part from the writings
of Paracelsus, then to our medical Luther, and not to the mythical
Benedictine monk, must be attributed a great revival in the search
for the Philosopher's Stone, for the Elixir of Life, for a universal
medicine, for the perpetuum mobile and for an aurum potabile.(37) I
reproduce, almost at random, a page from the fifth and last part of the
last will and testament of Basil Valentine (London, 1657), from which
you may judge the chemical spirit of the time.

     (36) Withington:  Medical History from the Earliest Times,
     London, 1891, Scientific Press, p. 317.

     (37) See Professor Stillman on the Basil Valentine hoax, Popular
     Science Monthly, New York, 1919, LXXXI, 591-600.

Out of the mystic doctrines of Paracelsus arose the famous "Brothers of
the Rosy Cross." "The brotherhood was possessed of the deepest knowledge
and science, the transmutation of metals, the perpetuum mobile and
the universal medicine were among their secrets; they were free from
sickness and suffering during their lifetime, though subject finally to
death."(38)

     (38) Ferguson:  Bibliotheca Chemica, Vol. II, p. 290.  For an
     account of Fludd and the English Rosicrucians see Craven's Life
     of Fludd, Kirkwall, 1902.

A school of a more rational kind followed directly upon the work of
Paracelsus, in which the first man of any importance was Van Helmont.
The Paracelsian Archeus was the presiding spirit in living creatures,
and worked through special local ferments, by which the functions of the
organs are controlled. Disease of any part represents a strike on the
part of the local Archeus, who refuses to work. Though full of fanciful
ideas, Van Helmont had the experimental spirit and was the first chemist
to discover the diversity of gases. Like his teacher, he was in revolt
against the faculty, and he has bitter things to say of physicians. He
got into trouble with the Church about the magnetic cure of wounds, as
no fewer than twenty-seven propositions incompatible with the Catholic
faith were found in his pamphlet (Ferguson). The Philosophus per ignem,
Toparcha in Merode, Royenborch, as he is styled in certain of his
writings, is not an easy man to tackle. I show the title-page of the
"Ortus Medicinae," the collection of his works by his son. As with the
pages of Paracelsus, there are many gems to be dug out. The counterblast
against bleeding was a useful protest, and to deny in toto its utility
in fever required courage--a quality never lacking in the Father of
Modern Chemistry, as he has been called.

A man of a very different type, a learned academic, a professor
of European renown, was Daniel Sennert of Wittenberg, the first to
introduce the systematic teaching of chemistry into the curriculum,
and who tried to harmonize the Galenists and Paracelsians. Franciscus
Sylvius, a disciple of Van Helmont, established the first chemical
laboratory in Europe at Leyden, and to him is due the introduction of
modern clinical teaching. In 1664 he writes: "I have led my pupils
by the hand to medical practice, using a method unknown at Leyden, or
perhaps elsewhere, i.e., taking them daily to visit the sick at the
public hospital. There I have put the symptoms of disease before their
eyes; have let them hear the complaints of the patients, and have asked
them their opinions as to the causes and rational treatment of each
case, and the reasons for those opinions. Then I have given my own
judgment on every point. Together with me they have seen the happy
results of treatment when God has granted to our cares a restoration of
health; or they have assisted in examining the body when the patient has
paid the inevitable tribute to death."(39)

     (39) Withington:  Medical History from the Earliest Times,
     London, 1894, pp. 312-313.

Glauber, Willis, Mayow, Lemery, Agricola and Stahl led up to Robert
Boyle, with whom modern chemistry may be said to begin. Even as late as
1716, Lady Mary Wortley Montagu in Vienna found that all had transferred
their superstitions from religion to chemistry; "scarcely a man of
opulence or fashion that has not an alchemist in his service." To one
scientific man of the period I must refer as the author of the first
scientific book published in England. Dryden sings:

     Gilbert shall live till load-stones cease to draw
     Or British fleets the boundless ocean awe.

And the verse is true, for by the publication in 1600 of the "De
Magnete" the science of electricity was founded. William Gilbert was a
fine type of the sixteenth-century physician, a Colchester man, educated
at St. John's College, Cambridge. Silvanus Thompson says: "He is beyond
question rightfully regarded as the Father of Electric Science. He
founded the entire subject of Terrestrial Magnetism. He also made
notable contributions to Astronomy, being the earliest English expounder
of Copernicus. In an age given over to metaphysical obscurities and
dogmatic sophistry, he cultivated the method of experiment and of
reasoning from observation, with an insight and success which entitles
him to be regarded as the father of the inductive method. That method,
so often accredited to Bacon, Gilbert was practicing years before
him."(40)

     (40) Silvanus P. Thompson:  Gilbert of Colchester, Father of
     Electrical Science, London, Chiswick Press, 1903, p. 3.

CHAPTER V -- THE RISE AND DEVELOPMENT OF MODERN MEDICINE

THE middle of the seventeenth century saw the profession thus far on
its way--certain objective features of disease were known, the art of
careful observation had been cultivated, many empirical remedies had
been discovered, the coarser structure of man's body had been well
worked out, and a good beginning had been made in the knowledge of how
the machinery worked--nothing more. What disease really was, where
it was, how it was caused, had not even begun to be discussed
intelligently.

An empirical discovery of the first importance marks the middle of the
century. The story of cinchona is of special interest, as it was the
first great specific in disease to be discovered. In 1638, the wife
of the Viceroy of Peru, the Countess of Chinchon, lay sick of an
intermittent fever in the Palace of Lima. A friend of her husband's,
who had become acquainted with the virtues, in fever, of the bark of
a certain tree, sent a parcel of it to the Viceroy, and the remedy
administered by her physician, Don Juan del Vego, rapidly effected
a cure. In 1640, the Countess returned to Spain, bringing with her
a supply of quina bark, which thus became known in Europe as "the
Countess's Powder" (pulvis Comitissae). A little later, her doctor
followed, bringing additional quantities. Later in the century,
the Jesuit Fathers sent parcels of the bark to Rome, whence it was
distributed to the priests of the community and used for the cure of
ague; hence the name of "Jesuits' bark." Its value was early recognized
by Sydenham and by Locke. At first there was a great deal of opposition,
and the Protestants did not like it because of its introduction by the
Jesuits. The famous quack, Robert Talbor, sold the secret of preparing
quinquina to Louis XIV in 1679 for two thousand louis d'or, a pension
and a title. That the profession was divided in opinion on the subject
was probably due to sophistication, or to the importation of other and
inert barks. It was well into the eighteenth century before its virtues
were universally acknowledged. The tree itself was not described until
1738, and Linnaeus established the genus "Chinchona" in honor of the
Countess.(1)

     (1) Clements R. Markham:  Peruvian Bark, John Murray, London,
     1880; Memoir of the Lady Anna di Osoria, Countess of Chinchona
     and Vice-Queen of Peru, 1874.

A step in advance followed the objective study of the changes wrought in
the body by disease. To a few of these the anatomists had already called
attention. Vesalius, always keen in his description of aberrations from
the normal, was one of the first to describe internal aneurysm. The
truth is, even the best of men had little or no appreciation of the
importance of the study of these changes. Sydenham scoffs at the value
of post-mortems.

Again we have to go back to Italy for the beginning of these studies,
this time to Florence, in the glorious days of Lorenzo the Magnificent.
The pioneer now is not a professor but a general practitioner, Antonio
Benivieni, of whom we know very little save that he was a friend of
Marsilio Ficino and of Angelo Poliziano, and that he practiced in
Florence during the last third of the fifteenth century, dying in 1502.
Through associations with the scholars of the day, he had become a
student of Greek medicine and he was not only a shrewd and accurate
observer of nature but a bold and successful practitioner. He had formed
the good habit of making brief notes of his more important cases, and
after his death these were found by his brother Jerome and published in
1507.(2) This book has a rare value as the record of the experience of
an unusually intelligent practitioner of the period. There are in all
111 observations, most of them commendably brief. The only one of any
length deals with the new "Morbus Gallicus," of which, in the short
period between its appearance and Benivieni's death, he had seen enough
to leave a very accurate description; and it is interesting to note that
even in those early days mercury was employed for its cure. The surgical
cases are of exceptional interest, and No. 38 refers to a case of angina
for which he performed a successful operation. This is supposed to have
been a tracheotomy, and if so, it is the first in the fourteen centuries
that had elapsed since the days of Antyllus.(3) There are other
important cases which show that he was a dexterous and fearless surgeon.
But the special interest of the work for us is that, for the first time
in modern literature, we have reports of post-mortem examinations made
specifically with a view to finding out the exact cause of death. Among
the 111 cases, there are post-mortem records of cases of gallstones,
abscess of the mesentery, thrombosis of the mesenteric veins, several
cases of heart disease, senile gangrene and one of cor villosum. From no
other book do we get so good an idea of a practitioner's experience at
this period; the notes are plain and straightforward, and singularly
free from all theoretical and therapeutic vagaries. He gives several
remarkable instances of faith healing.

     (2) De abditis nonnullis ac mirandis morborum et sanationum
     causis. 8th, Florence, Gandhi, 1507.

     (3) Possibly it was only a case of angina Ludovici, or
     retro-pharyngeal abscess.

To know accurately the anatomical changes that take place in disease is
of importance both for diagnosis and for treatment. The man who created
the science, who taught us to think anatomically of disease,
was Morgagni, whose "De sedibus et causis morborum per anatomen
indagatis"(4) is one of the great books in our literature. During the
seventeenth century, the practice of making post-mortem examinations
had extended greatly, and in the "Sepulchretum anatomicum" of Bonetus
(1679), these scattered fragments are collected.(5) But the work
of Morgagni is of a different type, for in it are the clinical and
anatomical observations of an able physician during a long and active
life. The work had an interesting origin. A young friend interested in
science and in medicine was fond of discoursing with Morgagni about his
preceptors, particularly Valsalva and Albertini, and sometimes the young
man inquired about Morgagni's own observations and thoughts. Yielding
to a strong wish, Morgagni consented to write his young friend familiar
letters describing his experiences. I am sorry that Morgagni does not
mention the name of the man to whom we are so much indebted, and who,
he states, was so pleased with the letters that he continually solicited
him to send more and more "till he drew me on so far as the seventieth;
. . . when I begged them of him in order to revise their contents; he
did not return them, till he had made me solemnly promise, that I would
not abridge any part thereof" (Preface).

     (4) Venice, 1761.

     (5) Boerhaave remarked that if a man wished to deserve or get a
     medical degree from ONE medical author let it be this. (James
     Atkinson: Medical Bibliography, 1834, 268.)

Born in 1682, Morgagni studied at Bologna under Valsalva and Albertini.
In 1711, he was elected professor of medicine at Padua. He published
numerous anatomical observations and several smaller works of less
importance. The great work which has made his name immortal in
the profession, appeared in his eightieth year, and represents the
accumulated experience of a long life. Though written in the form
of letters, the work is arranged systematically and has an index of
exceptional value. From no section does one get a better idea of the
character and scope of the work than from that relating to the heart
and arteries--affections of the pericardium, diseases of the valves,
ulceration, rupture, dilation and hypertrophy and affections of the
aorta are very fully described. The section on aneurysm of the
aorta remains one of the best ever written. It is not the anatomical
observations alone that make the work of unusual value, but the
combination of clinical with anatomical records. What could be more
correct than this account of angina pectoris--probably the first in the
literature? "A lady forty-two years of age, who for a long time, had
been a valetudinarian, and within the same period, on using pretty quick
exercise of body, she was subject to attacks of violent anguish in the
upper part of the chest on the left side, accompanied with a difficulty
of breathing, and numbness of the left arm; but these paroxysms soon
subsided when she ceased from exertion. In these circumstances, but with
cheerfulness of mind, she undertook a journey from Venice, purposing
to travel along the continent, when she was seized with a paroxysm, and
died on the spot. I examined the body on the following day.... The aorta
was considerably dilated at its curvature; and, in places, through
its whole tract, the inner surface was unequal and ossified. These
appearances were propagated into the arteria innominata. The aortic
valves were indurated...." He remarks, "The delay of blood in the aorta,
in the heart, in the pulmonary vessels, and in the vena cave, would
occasion the symptoms of which the woman complained during life; namely,
the violent uneasiness, the difficulty of breathing, and the numbness of
the arm."(6)

     (6) Cooke's Morgagni, Vol. 1, pp. 417-418. I cannot too warmly
     commend to young clinicians the reading of Morgagni.  English
     editions are available--Alexander's three-volume translation of
     1769 and Cooke's Abridgement (London, 1822), of which there was
     an American edition published in Boston in 1824.

Morgagni's life had as much influence as his work. In close
correspondence with the leading men of the day, with the young and
rising teachers and workers, his methods must have been a great
inspiration; and he came just at the right time. The profession was
literally ravaged by theories, schools and systems--iatromechanics,
iatrochemistry, humoralism, the animism of Stahl, the vitalistic
doctrines of Van Helmont and his followers--and into this metaphysical
confusion Morgagni came like an old Greek with his clear observation,
sensible thinking and ripe scholarship. Sprengel well remarks that "it
is hard to say whether one should admire most his rare dexterity and
quickness in dissection, his unimpeachable love of truth and justice in
his estimation of the work of others, his extensive scholarship and rich
classical style or his downright common sense and manly speech."

Upon this solid foundation the morbid anatomy of modern clinical
medicine was built. Many of Morgagni's contemporaries did not fully
appreciate the change that was in progress, and the value of the new
method of correlating the clinical symptoms and the morbid appearances.
After all, it was only the extension of the Hippocratic method
of careful observation--the study of facts from which reasonable
conclusions could be drawn. In every generation there had been men of
this type--I dare say many more than we realize--men of the Benivieni
character, thoroughly practical, clear-headed physicians. A model of
this sort arose in England in the middle of the seventeenth century,
Thomas Sydenham (1624-1689), who took men back to Hippocrates, just as
Harvey had led them back to Galen. Sydenham broke with authority
and went to nature. It is extraordinary how he could have been so
emancipated from dogmas and theories of all sorts. He laid down the
fundamental proposition, and acted upon it, that "all disease could be
described as natural history." To do him justice we must remember,
as Dr. John Brown says, "in the midst of what a mass of errors and
prejudices, of theories actively mischievous, he was placed, at a time
when the mania of hypothesis was at its height, and when the practical
part of his art was overrun and stultified by vile and silly nostrums"
("Horae Subsecivae," Vol. I, 4th ed., Edinburgh, 1882, p. 40).

Listen to what he says upon the method of the study of medicine: "In
writing therefore, such a natural history of diseases, every merely
philosophical hypothesis should be set aside, and the manifest and
natural phenomena, however minute, should be noted with the utmost
exactness. The usefulness of this procedure cannot be easily overrated,
as compared with the subtle inquiries and trifling notions of modern
writers, for can there be a shorter, or indeed any other way of coming
at the morbific causes, or discovering the curative indications than by
a certain perception of the peculiar symptoms? By these steps and helps
it was that the father of physic, the great Hippocrates, came to excel,
his theory being no more than an exact description or view of nature. He
found that nature alone often terminates diseases, and works a cure with
a few simple medicines, and often enough with no medicines at all."

Towards the end of the century many great clinical teachers arose, of
whom perhaps the most famous was Boerhaave, often spoken of as the Dutch
Hippocrates, who inspired a group of distinguished students. I have
already referred to the fact that Franciscus Sylvius at Leyden was the
first among the moderns to organize systematic clinical teaching. Under
Boerhaave, this was so developed that to this Dutch university students
flocked from all parts of Europe. After teaching botany and chemistry,
Boerhaave succeeded to the chair of physic in 1714. With an unusually
wide general training, a profound knowledge of the chemistry of the
day and an accurate acquaintance with all aspects of the history of
the profession, he had a strongly objective attitude of mind towards
disease, following closely the methods of Hippocrates and Sydenham. He
adopted no special system, but studied disease as one of the phenomena
of nature. His clinical lectures, held bi-weekly, became exceedingly
popular and were made attractive not less by the accuracy and care with
which the cases were studied than by the freedom from fanciful doctrines
and the frank honesty of the man. He was much greater than his published
work would indicate, and, as is the case with many teachers of the first
rank, his greatest contributions were his pupils. No other teacher of
modern times has had such a following. Among his favorite pupils may
be mentioned Haller, the physiologist, and van Swieten and de Haen, the
founders of the Vienna school.

In Italy, too, there were men who caught the new spirit, and appreciated
the value of combining morbid anatomy with clinical medicine. Lancisi,
one of the early students of disease of the heart, left an excellent
monograph on the subject, and was the first to call special attention
to the association of syphilis with cardio-vascular disease. A younger
contemporary of his at Rome, Baglivi, was unceasing in his call to
the profession to return to Hippocratic methods, to stop reading
philosophical theories and to give up what he calls the "fatal itch" to
make systems.

The Leyden methods of instruction were carried far and wide throughout
Europe; into Edinburgh by John Rutherford, who began to teach at the
Royal Infirmary in 1747, and was followed by Whytt and by Cullen; into
England by William Saunders of Guy's Hospital. Unfortunately the
great majority of clinicians could not get away from the theoretical
conceptions of disease, and Cullen's theory of spasm and atony exercised
a profound influence on practice, particularly in this country, where it
had the warm advocacy of Benjamin Rush. Even more widespread became the
theories of a pupil of Cullen's, John Brown, who regarded excitability
as the fundamental property of all living creatures: too much of this
excitability produced what were known as sthenic maladies, too little,
asthenic; on which principles practice was plain enough. Few systems of
medicine have ever stirred such bitter controversy, particularly on the
Continent, and in Charles Creighton's account of Brown(7) we read
that as late as 1802 the University of Gottingen was so convulsed by
controversies as to the merits of the Brunonian system that contending
factions of students in enormous numbers, not unaided by the professors,
met in combat in the streets on two consecutive days and had to be
dispersed by a troop of Hanoverian horse.

     (7) Dictionary of National Biography, London, 1886, VII, 14-17.

But the man who combined the qualities of Vesalius, Harvey and Morgagni
in an extraordinary personality was John Hunter. He was, in the first
place, a naturalist to whom pathological processes were only a small
part of a stupendous whole, governed by law, which, however, could
never be understood until the facts had been accumulated, tabulated and
systematized. By his example, by his prodigious industry, and by his
suggestive experiments he led men again into the old paths of Aristotle,
Galen and Harvey. He made all thinking physicians naturalists, and he
lent a dignity to the study of organic life, and re-established a close
union between medicine and the natural sciences. Both in Britain and
Greater Britain, he laid the foundation of the great collections and
museums, particularly those connected with the medical schools. The
Wistar-Horner and the Warren Museums in this country originated with men
greatly influenced by Hunter. He was, moreover, the intellectual father
of that interesting group of men on this side of the Atlantic who, while
practising as physicians, devoted much time and labor to the study of
natural history; such men as Benjamin Smith Barton, David Hossack, Jacob
Bigelow, Richard Harlan, John D. Godman, Samuel George Morton, John
Collins Warren, Samuel L. Mitchill and J. Ailken Meigs. He gave an
immense impetus in Great Britain to the study of morbid anatomy, and
his nephew, Matthew Baillie, published the first important book on the
subject in the English language.

Before the eighteenth century closed practical medicine had made great
advance. Smallpox, though not one of the great scourges like plague
or cholera, was a prevalent and much dreaded disease, and in civilized
countries few reached adult life without an attack. Edward Jenner, a
practitioner in Gloucestershire, and the pupil to whom John Hunter gave
the famous advice: "Don't think, try!" had noticed that milkmaids
who had been infected with cowpox from the udder of the cow were
insusceptible to smallpox. I show you here the hand of Sarah Nelmes with
cowpox, 1796. A vague notion had prevailed among the dairies from time
immemorial that this disease was a preventive of the smallpox. Jenner
put the matter to the test of experiment. Let me quote here his own
words: "The first experiment was made upon a lad of the name of Phipps,
in whose arm a little vaccine virus was inserted, taken from the hand
of a young woman who had been accidentally infected by a cow.
Notwithstanding the resemblance which the pustule, thus excited on
the boy's arm, bore to variolous inoculation, yet as the indisposition
attending it was barely perceptible, I could scarcely persuade myself
the patient was secure from the Small Pox. However, on his being
inoculated some months afterwards, it proved that he was secure."(8)
The results of his experiments were published in a famous small quarto
volume in 1798.(*) From this date, smallpox has been under control.
Thanks to Jenner, not a single person in this audience is pockmarked!
A hundred and twenty-five years ago, the faces of more than half of you
would have been scarred. We now know the principle upon which protection
is secured: an active acquired immunity follows upon an attack of a
disease of a similar nature. Smallpox and cowpox are closely allied and
the substances formed in the blood by the one are resistant to the
virus of the other. I do not see how any reasonable person can oppose
vaccination or decry its benefits. I show you the mortality figures(9)
of the Prussian Army and of the German Empire. A comparison with
the statistics of the armies of other European countries in which
revaccination is not so thoroughly carried out is most convincing of its
efficacy.

     (8) Edward Jenner:  The Origin of the Vaccine Inoculation,
     London, 1801.

     (*) Reprinted by Camac:  Epoch-making Contributions to Medicine,
     etc., 1909.--Ed.

     (9) Jockmann:  Pocken und Vaccinationlehre, 1913.

The early years of the century saw the rise of modern clinical medicine
in Paris. In the art of observation men had come to a standstill.
I doubt very much whether Corvisart in 1800 was any more skilful in
recognizing a case of pneumonia than was Aretaeus in the second century
A. D. But disease had come to be more systematically studied; special
clinics were organized, and teaching became much more thorough. Anyone
who wishes to have a picture of the medical schools in Europe in the
first few years of the century, should read the account of the travels
of Joseph Frank of Vienna.(10) The description of Corvisart is of a
pioneer in clinical teaching whose method remains in vogue today
in France--the ward visit, followed by a systematic lecture in the
amphitheatre. There were still lectures on Hippocrates three times a
week, and bleeding was the principal plan of treatment: one morning
Frank saw thirty patients, out of one hundred and twelve, bled!
Corvisart was the strong clinician of his generation, and his accurate
studies on the heart were among the first that had concentrated
attention upon a special organ. To him, too, is due the reintroduction
of the art of percussion in internal disease discovered by Auenbrugger
in 1761.

     (10) Joseph Frank:  Reise nach Paris (etc.), Wien, 1804-05.

The man who gave the greatest impetus to the study of scientific
medicine at this time was Bichat, who pointed out that the pathological
changes in disease were not so much in organs as in tissues. His
studies laid the foundation of modern histology. He separated the
chief constituent elements of the body into various tissues possessing
definite physical and vital qualities. "Sensibility and contractability
are the fundamental qualities of living matter and of the life of our
tissues. Thus Bichat substituted for vital forces 'vital properties,'
that is to say, a series of vital forces inherent in the different
tissues."(11) His "Anatomic Generale," published in 1802, gave an
extraordinary stimulus to the study of the finer processes of disease,
and his famous "Recherches sur la Vie et sur la Mort" (1800) dealt
a death-blow to old iatromechanical and iatrochemical views. His
celebrated definition may be quoted: "La vie est l'ensemble des
proprietes vitales qui resistent aux proprietes physiques, ou bien la
vie est l'ensemble des fonctions qui resistent a la mort." (Life is the
sum of the vital properties that withstand the physical properties,
or, life is the sum of the functions that withstand death.) Bichat is
another pathetic figure in medical history. His meteoric career ended
in his thirty-first year: he died a victim of a post-mortem wound
infection. At his death, Corvisart wrote Napoleon: "Bichat has just died
at the age of thirty. That battlefield on which he fell is one which
demands courage and claims many victims. He has advanced the science of
medicine. No one at his age has done so much so well."

     (11) E. Boinet:  Les doctrines medicules, leur evolution, Paris,
     1907, pp. 85-86.

It was a pupil of Corvisart, Rene Theophile Laennec, who laid the
foundation of modern clinical medicine. The story of his life is well
known. A Breton by birth, he had a hard, up-hill struggle as a young
man--a struggle of which we have only recently been made aware by the
publication of a charming book by Professor Rouxeau of Nantes--"Laennec
avant 1806." Influenced by Corvisart, he began to combine the accurate
study of cases in the wards with anatomical investigations in the
dead-house. Before Laennec, the examination of a patient had been
largely by sense of sight, supplemented by that of touch, as in
estimating the degree of fever, or the character of the pulse.
Auenbrugger's "Inventum novum" of percussion, recognized by Corvisart,
extended the field; but the discovery of auscultation by Laennec, and
the publication of his work--"De l'Auscultation Mediate," 1819,--marked
an era in the study of medicine. The clinical recognition of individual
diseases had made really very little progress; with the stethoscope
begins the day of physical diagnosis. The clinical pathology of the
heart, lungs and abdomen was revolutionized. Laennec's book is in the
category of the eight or ten greatest contributions to the science
of medicine.(*) His description of tuberculosis is perhaps the most
masterly chapter in clinical medicine. This revolution was effected by
a simple extension of the Hippocratic method from the bed to the
dead-house, and by correlating the signs and symptoms of a disease with
its anatomical appearances.

     (*) John Forbes's translation of Auenbrugger and part of his
     translation of Lacnnec are reprinted in Camac's Epoch-making
     Contributions, etc., 1909.--Ed.

The pupils and successors of Corvisart--Bayle, Andral, Bouillaud,
Chomel, Piorry, Bretonneau, Rayer, Cruveilhier and Trousseau--brought a
new spirit into the profession. Everywhere the investigation of disease
by clinical-pathological methods widened enormously the diagnostic
powers of the physician. By this method Richard Bright, in 1836, opened
a new chapter on the relation of disease of the kidney to dropsy, and to
albuminous urine. It had already been shown by Blackwell and by Wells,
the celebrated Charleston (S.C.) physician, in 1811, that the urine
contained albumin in many cases of dropsy, but it was not until
Bright began a careful investigation of the bodies of patients who had
presented these symptoms, that he discovered the association of various
forms of disease of the kidney with anasarca and albuminous urine. In no
direction was the harvest of this combined study more abundant than in
the complicated and confused subject of fever. The work of Louis and of
his pupils, W.W. Gerhard and others, revealed the distinction between
typhus and typhoid fever, and so cleared up one of the most obscure
problems in pathology. By Morgagni's method of "anatomical thinking,"
Skoda in Vienna, Schonlein in Berlin, Graves and Stokes in Dublin,
Marshall Hall, C. J. B. Williams and many others introduced the new and
exact methods of the French and created a new clinical medicine. A
very strong impetus was given by the researches of Virchow on cellular
pathology, which removed the seats of disease from the tissues,
as taught by Bichat, to the individual elements, the cells. The
introduction of the use of the microscope in clinical work widened
greatly our powers of diagnosis, and we obtained thereby a very much
clearer conception of the actual processes of disease. In another way,
too, medicine was greatly helped by the rise of experimental pathology,
which had been introduced by John Hunter, was carried along by Magendie
and others, and reached its culmination in the epoch-making researches
of Claude Bernard. Not only were valuable studies made on the action of
drugs, but also our knowledge of cardiac pathology was revolutionized
by the work of Traube, Cohnheim and others. In no direction did the
experimental method effect such a revolution as in our knowledge of the
functions of the brain. Clinical neurology, which had received a great
impetus by the studies of Todd, Romberg, Lockhart Clarke, Duchenne and
Weir Mitchell, was completely revolutionized by the experimental work
of Hitzig, Fritsch and Ferrier on the localization of functions in
the brain. Under Charcot, the school of French neurologists gave great
accuracy to the diagnosis of obscure affections of the brain and spinal
cord, and the combined results of the new anatomical, physiological and
experimental work have rendered clear and definite what was formerly the
most obscure and complicated section of internal medicine. The end of
the fifth decade of the century is marked by a discovery of supreme
importance. Humphry Davy had noted the effects of nitrous oxide. The
exhilarating influence of sulphuric ether had been casually studied, and
Long of Georgia had made patients inhale the vapor until anaesthetic and
had performed operations upon them when in this state; but it was not
until October 16, 1846, in the Massachusetts General Hospital, that
Morton, in a public operating room, rendered a patient insensible with
ether and demonstrated the utility of surgical anaesthesia. The rival
claims of priority no longer interest us, but the occasion is one of
the most memorable in the history of the race. It is well that our
colleagues celebrate Ether Day in Boston--no more precious boon has ever
been granted to suffering humanity.(*)

     (*) Cf. Osler:  Proc. Roy. Soc. Med., XI, Sect. Hist.  Med., pp.
     65-69, 1918, or, Annals Med. Hist., N.Y., I, 329-332. Cf. also
     Morton's publications reprinted in Camac's book cited above.--Ed.

In 1857, a young man, Louis Pasteur, sent to the Lille Scientific
Society a paper on "Lactic Acid Fermentation" and in December of the
same year presented to the Academy of Sciences in Paris a paper on
"Alcoholic Fermentation" in which he concluded that "the deduplication
of sugar into alcohol and carbonic acid is correlative to a phenomenon
of life." A new era in medicine dates from those two publications. The
story of Pasteur's life should be read by every student.(*) It is one of
the glories of human literature, and, as a record of achievement and of
nobility of character, is almost without an equal.

     (*) Osler wrote a preface for the 1911 English edition of the
     Life by Vallery-Radot.--Ed.

At the middle of the last century we did not know much more of the
actual causes of the great scourges of the race, the plagues, the fevers
and the pestilences, than did the Greeks. Here comes Pasteur's great
work. Before him Egyptian darkness; with his advent a light that
brightens more and more as the years give us ever fuller knowledge. The
facts that fevers were catching, that epidemics spread, that infection
could remain attached to articles of clothing, etc., all gave support to
the view that the actual cause was something alive, a contagium vivum.
It was really a very old view, the germs of which may be found in the
Fathers, but which was first clearly expressed--so far as I know--by
Fracastorius, the Veronese physician, in the sixteenth century, who
spoke of the seeds of contagion passing from one person to another;(12)
and he first drew a parallel between the processes of contagion and
the fermentation of wine. This was more than one hundred years before
Kircher, Leeuwenhoek and others began to use the microscope and to see
animalcula, etc., in water, and so give a basis for the "infinitely
little" view of the nature of disease germs. And it was a study of the
processes of fermentation that led Pasteur to the sure ground on which
we now stand.

     (12) Varro, in De Re Rustica, Bk. I, 12 (circa 40 B.C.), speaks
     of minute organisms which the eye cannot see and which enter the
     body and cause disease.

Out of these researches arose a famous battle which kept Pasteur hard at
work for four or five years--the struggle over spontaneous generation.
It was an old warfare, but the microscope had revealed a new world, and
the experiments on fermentation had lent great weight to the omne vivum
ex ovo doctrine. The famous Italians, Redi and Spallanzani, had led the
way in their experiments, and the latter had reached the conclusion
that there is no vegetable and no animal that has not its own germ. But
heterogenesis became the burning question, and Pouchet in France, and
Bastian in England, led the opposition to Pasteur. The many famous
experiments carried conviction to the minds of scientific men, and
destroyed forever the old belief in spontaneous generation. All along,
the analogy between disease and fermentation must have been in Pasteur's
mind; and then came the suggestion, "What would be most desirable is to
push those studies far enough to prepare the road for a serious
research into the origin of various diseases." If the changes in lactic,
alcoholic and butyric fermentations are due to minute living organisms,
why should not the same tiny creatures make the changes which occur
in the body in the putrid and suppurative diseases? With an accurate
training as a chemist, having been diverted in his studies upon
fermentation into the realm of biology, and nourishing a strong
conviction of the identity between putrefactive changes of the body
and fermentation, Pasteur was well prepared to undertake investigations
which had hitherto been confined to physicians alone.

So impressed was he with the analogy between fermentation and the
infectious diseases that, in 1863, he assured the French Emperor of
his ambition "to arrive at the knowledge of the causes of putrid and
contagious diseases." After a study upon the diseases of wines, which
has had most important practical bearings, an opportunity arose which
changed the whole course of his career, and profoundly influenced the
development of medical science. A disease of the silkworm had, for some
years, ruined one of the most important industries in France, and in
1865 the Government asked Pasteur to give up his laboratory work and
teaching, and to devote his whole energies to the task of investigating
it. The story of the brilliant success which followed years of
application to the problem will be read with deep interest by every
student of science. It was the first of his victories in the application
of the experimental methods of a trained chemist to the problems
of biology, and it placed his name high in the group of the most
illustrious benefactors of practical industries.

In a series of studies on the diseases of beer, and on the mode of
production of vinegar, he became more and more convinced that these
studies on fermentation had given him the key to the nature of the
infectious diseases. It is a remarkable fact that the distinguished
English philosopher of the seventeenth century, the man who more
than anyone else of his century appreciated the importance of the
experimental method, Robert Boyle, had said that he who could discover
the nature of ferments and fermentation, would be more capable than
anyone else of explaining the nature of certain diseases.

In 1876 there appeared in Cohn's "Beitrage zur Morphologie der Pflanzen"
(II, 277-310), a paper on the "AEtiology of Anthrax" by a German
district physician in Wollstein, Robert Koch, which is memorable in our
literature as the starting point of a new method of research into
the causation of infectious diseases. Koch demonstrated the constant
presence of germs in the blood of animals dying from the disease. Years
before, those organisms had been seen by Pollender and Davaine, but
the epoch-making advance of Koch was to grow those organisms in a pure
culture outside the body, and to produce the disease artificially
by inoculating animals with the cultures Koch is really our medical
Galileo, who, by means of a new technique,--pure cultures and isolated
staining,--introduced us to a new world. In 1878, followed his study on
the "AEtiology of Wound Infections," in which he was able to demonstrate
conclusively the association of micro-organisms with the disease. Upon
those two memorable researches made by a country doctor rests the modern
science of bacteriology.

The next great advance was the discovery by Pasteur of the possibility
of so attenuating, or weakening, the poison that an animal inoculated
had a slight attack, recovered and was then protected against the
disease. More than eighty years had passed since on May 14, 1796, Jenner
had vaccinated a child with cowpox and proved that a slight attack of
one disease protected the body from a disease of an allied nature. An
occasion equally famous in the history of medicine was a day in 1881,
when Pasteur determined that a flock of sheep vaccinated with the
attenuated virus of anthrax remained well, when every one of the
unvaccinated infected from the same material had died. Meanwhile, from
Pasteur's researches on fermentation and spontaneous generation, a
transformation had been initiated in the practice of surgery, which,
it is not too much to say, has proved one of the greatest boons ever
conferred upon humanity. It had long been recognized that, now and
again, a wound healed without the formation of pus, that is, without
suppuration, but both spontaneous and operative wounds were almost
invariably associated with that process; and, moreover, they frequently
became putrid, as it was then called,--infected, as we should say,--the
general system became involved and the patient died of blood poisoning.
So common was this, particularly in old, ill-equipped hospitals, that
many surgeons feared to operate, and the general mortality in all
surgical cases was very high. Believing that it was from outside that
the germs came which caused the decomposition of wounds, just as
from the atmosphere the sugar solution got the germs which caused the
fermentation, a young surgeon in Glasgow, Joseph Lister, applied the
principles of Pasteur's experiments to their treatment. From Lister's
original paper(*) I quote the following: "Turning now to the question
how the atmosphere produces decomposition of organic substances, we find
that a flood of light has been thrown upon this most important subject
by the philosophic researches of M. Pasteur, who has demonstrated by
thoroughly convincing evidence that it is not to its oxygen or to any of
its gaseous constituents that the air owes this property, but to minute
particles suspended in it, which are the germs of various low forms
of life, long since revealed by the microscope, and regarded as merely
accidental concomitants of putrescence, but now shown by Pasteur to
be its essential cause, resolving the complex organic compounds into
substances of simpler chemical constitution, just as the yeast-plant
converts sugar into alcohol and carbonic acid." From these beginnings
modern surgery took its rise, and the whole subject of wound infection,
not only in relation to surgical diseases, but to child-bed fever, forms
now one of the most brilliant chapters in the history of preventive
medicine.

     (*) Lancet, March 16, 1867.  (Cf. Camac:  Epoch-making
     Contributions, etc., 1909, p. 7.--Ed.)

With the new technique and experimental methods, the discovery of the
specific germs of many of the more important acute infections followed
each other with bewildering rapidity: typhoid fever, diphtheria,
cholera, tetanus, plague, pneumonia, gonorrhoea and, most important of
all, tuberculosis. It is not too much to say that the demonstration
by Koch of the "bacillus tuberculosis" (1882) is, in its far-reaching
results, one of the most momentous discoveries ever made.

Of almost equal value have been the researches upon the protozoan forms
of animal life, as causes of disease. As early as 1873, spirilla were
demonstrated in relapsing fever. Laveran proved the association of
haematozoa with malaria in 1880. In the same year, Griffith Evans
discovered trypanosomes in a disease of horses and cattle in India, and
the same type of parasite was found in the sleeping sickness. Amoebae
were demonstrated in one form of dysentery, and in other tropical
diseases protozoa were discovered, so that we were really prepared for
the announcement in 1905, by Schaudinn, of the discovery of a protozoan
parasite in syphilis. Just fifty years had passed since Pasteur had
sent in his paper on "Lactic Acid Fermentation" to the Lille Scientific
Society--half a century in which more had been done to determine the
true nature of disease than in all the time that had passed since
Hippocrates. Celsus makes the oft-quoted remark that to determine
the cause of a disease often leads to the remedy,(*) and it is the
possibility of removing the cause that gives such importance to the new
researches on disease.

     (*) "Et causae quoque estimatio saepe morbum solvit," Celsus,
     Lib.  I, Prefatio.--Ed.

INTERNAL SECRETIONS

ONE of the greatest contributions of the nineteenth century to
scientific medicine was the discovery of the internal secretions of
organs. The basic work on the subject was done by Claude Bernard, a
pupil of the great Magendie, whose saying it is well to remember--"When
entering a laboratory one should leave theories in the cloakroom." More
than any other man of his generation, Claude Bernard appreciated the
importance of experiment in practical medicine. For him the experimental
physician was the physician of the future--a view well borne out by the
influence his epoch-making work has had on the treatment of disease. His
studies on the glycogenic functions of the liver opened the way for the
modern fruitful researches on the internal secretions of the various
glands. About the same time that Bernard was developing the laboratory
side of the problem, Addison, a physician to Guy's Hospital, in 1855,
pointed out the relation of a remarkable group of symptoms to disease
of the suprarenal glands, small bodies situated above the kidneys, the
importance of which had not been previously recognized. With the loss
of the function of these glands by disease, the body was deprived of
something formed by them which was essential to its proper working.
Then, in the last third of the century, came in rapid succession the
demonstration of the relations of the pancreas to diabetes, of the vital
importance of the thyroid gland and of the pituitary body. Perhaps no
more striking illustration of the value of experimental medicine has
ever been given than that afforded by the studies upon those glands.

The thyroid body, situated in the neck and the enlargement of which is
called goitre, secretes substances which pass into the blood, and
which are necessary for the growth of the body in childhood, for the
development of the mind and for the nutrition of the tissues of the
skin. If, following an infectious disease, a child has wasting of this
gland, or if, living in a certain district, it has a large goitre,
normal development does not take place, and the child does not grow in
mind or body and becomes what is called a cretin. More than this--if in
adult life the gland is completely removed, or if it wastes, a somewhat
similar condition is produced, and the patient in time loses his mental
powers and becomes fat and flabby--myxedematous. It has been shown
experimentally in various ways that the necessary elements of the
secretion can be furnished by feeding with the gland or its extracts,
and that the cretinoid or myxedematous conditions could thus be cured or
prevented.

Experimental work has also demonstrated the functions of the suprarenal
glands and explained the symptoms of Addison's disease, and chemists
have even succeeded in making synthetically the active principle
adrenalin.

There is perhaps no more fascinating story in the history of science
than that of the discovery of these so-called ductless glands. Part
of its special interest is due to the fact that clinicians, surgeons,
experimental physiologists, pathologists and chemists have all combined
in splendid teamwork to win the victory. No such miracles have ever
before been wrought by physicians as those which we see in connection
with the internal secretion of the thyroid gland. The myth of bringing
the dead back to life has been associated with the names of many great
healers since the incident of Empedocles and Pantheia, but nowadays the
dead in mind and the deformed in body may be restored by the touch
of the magic wand of science. The study of the interaction of these
internal secretions, their influence upon development, upon mental
process and upon disorders of metabolism is likely to prove in the
future of a benefit scarcely less remarkable than that which we have
traced in the infectious diseases.

CHEMISTRY

IT is not making too strong a statement to say that the chemistry and
chemical physics of the nineteenth century have revolutionized
the world. It is difficult to realize that Liebig's famous Giessen
laboratory, the first to be opened to students for practical study, was
founded in the year 1825. Boyle, Cavendish, Priestley, Lavoisier, Black,
Dalton and others had laid a broad foundation, and Young, Frauenhofer,
Rumford, Davy, Joule, Faraday, Clerk-Maxwell, Helmholtz and others
built upon that and gave us the new physics and made possible our age
of electricity. New technique and new methods have given a powerful
stimulus to the study of the chemical changes that take place in the
body, which, only a few years ago, were matters largely of speculation.
"Now," in the words of Professor Lee, "we recognize that, with its
living and its non-living substances inextricably intermingled, the
body constitutes an intensive chemical laboratory in which there is ever
occurring a vast congeries of chemical reactions; both constructive and
destructive processes go on; new protoplasm takes the place of old. We
can analyze the income of the body and we can analyze its output, and
from these data we can learn much concerning the body's chemistry. A
great improvement in the method of such work has recently been secured
by the device of inclosing the person who is the subject of the
experiment in a respiration calorimeter. This is an air-tight chamber,
artificially supplied with a constant stream of pure air, and from which
the expired air, laden with the products of respiration, is withdrawn
for purposes of analysis. The subject may remain in the chamber for
days, the composition of all food and all excrete being determined, and
all heat that is given off being measured. Favorable conditions are
thus established for an exact study of many problems of nutrition. The
difficulties increase when we attempt to trace the successive steps in
the corporeal pathway of molecule and atom. Yet these secrets of the
vital process are also gradually being revealed. When we remember that
it is in this very field of nutrition that there exist great popular
ignorance and a special proneness to fad and prejudice, we realize how
practically helpful are such exact studies of metabolism."(13)

     (13) Frederick S. Lee, Ph.D.: Scientific Features of Modern
     Medicine, New York, 1911.  I would like to call attention to this
     work of Professor Lee's as presenting all the scientific features
     of modern medicine in a way admirably adapted for anyone, lay or
     medical, who wishes to get a clear sketch of them.

CHAPTER VI -- THE RISE OF PREVENTIVE MEDICINE

THE story so far has been of men and of movements--of men who have,
consciously or unconsciously, initiated great movements, and of
movements by which, nolens volens, the men of the time were moulded and
controlled. Hippocrates, in the tractate on "Ancient Medicine," has a
splendid paragraph on the attitude of mind towards the men of the past.
My attention was called to it one day in the Roman Forum by Commendatore
Boni, who quoted it as one of the great sayings of antiquity. Here it
is: "But on that account, I say, we ought not to reject the ancient Art,
as if it were not, and had not been properly founded, because it did
not attain accuracy in all things, but rather, since it is capable of
reaching to the greatest exactitude by reasoning, to receive it and
admire its discoveries, made from a state of great ignorance, and as
having been well and properly made, and not from chance."(1)

     (1) The Works of Hippocrates, Adams, Vol. I, p. 168, London, 1849
     (Sydenham Society).

I have tried to tell you what the best of these men in successive ages
knew, to show you their point of outlook on the things that interest
us. To understand the old writers one must see as they saw, feel as they
felt, believe as they believed--and this is hard, indeed impossible! We
may get near them by asking the Spirit of the Age in which they lived
to enter in and dwell with us, but it does not always come. Literary
criticism is not literary history--we have no use here for the former,
but to analyze his writings is to get as far as we can behind the
doors of a man's mind, to know and appraise his knowledge, not from our
standpoint, but from that of his contemporaries, his predecessors and
his immediate successors. Each generation has its own problems to face,
looks at truth from a special focus and does not see quite the same
outlines as any other. For example, men of the present generation
grow up under influences very different from those which surrounded my
generation in the seventies of the last century, when Virchow and
his great contemporaries laid the sure and deep foundations of modern
pathology. Which of you now knows the "Cellular Pathology" as we did? To
many of you it is a closed book,--to many more Virchow may be thought a
spent force. But no, he has only taken his place in a great galaxy. We
do not forget the magnitude of his labors, but a new generation has new
problems--his message was not for you--but that medicine today runs in
larger moulds and turns out finer castings is due to his life and work.
It is one of the values of lectures on the history of medicine to
keep alive the good influences of great men even after their positive
teaching is antiquated. Let no man be so foolish as to think that he has
exhausted any subject for his generation. Virchow was not happy when he
saw the young men pour into the old bottle of cellular pathology the new
wine of bacteriology. Lister could never understand how aseptic surgery
arose out of his work. Ehrlich would not recognize his epoch-making
views on immunity when this generation has finished with them. I believe
it was Hegel who said that progress is a series of negations--the
denial today of what was accepted yesterday, the contradiction by each
generation of some part at least of the philosophy of the last; but all
is not lost, the germ plasm remains, a nucleus of truth to be fertilized
by men often ignorant even of the body from which it has come. Knowledge
evolves, but in such a way that its possessors are never in sure
possession. "It is because science is sure of nothing that it is always
advancing" (Duclaux).

History is the biography of the mind of man, and its educational
value is in direct proportion to the completeness of our study of the
individuals through whom this mind has been manifested. I have tried
to take you back to the beginnings of science, and to trace its gradual
development, which is conditioned by three laws. In the first place,
like a living organism, truth grows, and its gradual evolution may
be traced from the tiny germ to the mature product. Never springing,
Minerva-like, to full stature at once, truth may suffer all the hazards
incident to generation and gestation. Much of history is a record of the
mishaps of truths which have struggled to the birth, only to die or else
to wither in premature decay. Or the germ may be dormant for centuries,
awaiting the fullness of time.

Secondly, all scientific truth is conditioned by the state of knowledge
at the time of its announcement. Thus, at the beginning of the
seventeenth century, the science of optics and mechanical appliances had
not made possible (so far as the human mind was concerned) the existence
of blood capillaries and blood corpuscles. Jenner could not have
added to his "Inquiry" a study on immunity; Sir William Perkin and the
chemists made Koch technique possible; Pasteur gave the conditions that
produced Lister; Davy and others furnished the preliminaries necessary
for anaesthesia. Everywhere we find this filiation, one event following
the other in orderly sequence--"Mind begets mind," as Harvey (De
Generatione) says; "opinion is the source of opinion. Democritus with
his atoms, and Eudoxus with his chief good which he placed in pleasure,
impregnated Epicurus; the four elements of Empedocles, Aristotle;
the doctrines of the ancient Thebans, Pythagoras and Plato; geometry,
Euclid."(2)

     (2) Works of William Harvey, translated by Robert Willis, London,
     1847, p. 532.

And, thirdly, to scientific truth alone may the homo mensura principle
be applied, since of all mental treasures of the race it alone compels
general acquiescence. That this general acquiescence, this aspect of
certainty, is not reached per saltum, but is of slow, often of difficult
growth,--marked by failures and frailties, but crowned at last with
an acceptance accorded to no other product of mental activity,--is
illustrated by every important discovery from Copernicus to Darwin.

The difficulty is to get men to the thinking level which compels the
application of scientific truths. Protagoras, that "mighty-wise man,"
as Socrates called him, who was responsible for the aphorism that man
is the measure of all things, would have been the first to recognize the
folly of this standard for the people at large. But we have gradually
reached a stage in which knowledge is translated into action, made
helpful for suffering humanity, just as the great discoveries in physics
and chemistry have been made useful in the advance of civilization.
We have traced medicine through a series of upward steps--a primitive
stage, in which it emerged from magic and religion into an empirical
art, as seen among the Egyptians and Babylonians; a stage in which the
natural character of disease was recognized and the importance of its
study as a phenomenon of nature was announced; a stage in which the
structure and functions of the human body were worked out; a stage in
which the clinical and anatomical features of disease were determined;
a stage in which the causes of disorders were profitably studied, and
a final stage, into which we have just entered, the application of the
knowledge for their prevention. Science has completely changed man's
attitude towards disease.

Take a recent concrete illustration. A couple of years ago in
Philadelphia and in some other parts of the United States, a very
peculiar disease appeared, characterized by a rash upon the skin and
moderate fever, and a constitutional disturbance proportionate to the
extent and severity of the eruption. The malady first broke out in the
members of a crew of a private yacht; then in the crews of other boats,
and among persons living in the boarding-houses along the docks. It was
the cause of a great deal of suffering and disability.

There were three courses open: to accept the disease as a visitation
of God, a chastening affliction sent from above, and to call to aid the
spiritual arm of the church. Except the "Peculiar People" few now take
this view or adopt this practice. The Christian Scientist would probably
deny the existence of the rash and of the fever, refuse to recognize
the itching and get himself into harmony with the Infinite. Thirdly, the
method of experimental medicine.

First, the conditions were studied under which the individual cases
occurred. The only common factor seemed to be certain straw mattresses
manufactured by four different firms, all of which obtained the straw
from the same source.

The second point was to determine the relation of the straw to the rash.
One of the investigators exposed a bare arm and shoulder for an hour
between two mattresses. Three people voluntarily slept on the mattresses
for one night. Siftings from the straw were applied to the arm,
under all of which circumstances the rash quickly developed, showing
conclusively the relation of the straw to the disease.

Thirdly, siftings from the straw and mattresses which had been
thoroughly disinfected failed to produce the rash.

And fourthly, careful inspection of the siftings of the straw disclosed
living parasites, small mites, which when applied to the skin quickly
produced the characteristic eruption.

SANITATION

WHEN the thoughtful historian gets far enough away from the nineteenth
century to see it as a whole, no single feature will stand out with
greater distinctness than the fulfilment of the prophecy of Descartes
that we could be freed from an infinity of maladies both of body and
mind if we had sufficient knowledge of their causes and of all the
remedies with which nature has provided us. Sanitation takes its place
among the great modern revolutions--political, social and intellectual.
Great Britain deserves the credit for the first practical recognition of
the maxim salus populi suprema lex. In the middle and latter part of
the century a remarkable group of men, Southwood Smith, Chadwick, Budd,
Murchison, Simon, Acland, Buchanan, J.W. Russell and Benjamin Ward
Richardson, put practical sanitation on a scientific basis. Even
before the full demonstration of the germ theory, they had grasped the
conception that the battle had to be fought against a living contagion
which found in poverty, filth and wretched homes the conditions for its
existence. One terrible disease was practically wiped out in twenty-five
years of hard work. It is difficult to realize that within the memory of
men now living, typhus fever was one of the great scourges of our large
cities, and broke out in terrible epidemics--the most fatal of all to
the medical profession. In the severe epidemic in Ireland in the forties
of the last century, one fifth of all the doctors in the island died
of typhus. A better idea of the new crusade, made possible by new
knowledge, is to be had from a consideration of certain diseases against
which the fight is in active progress.

Nothing illustrates more clearly the interdependence of the sciences
than the reciprocal impulse given to new researches in pathology
and entomology by the discovery of the part played by insects in the
transmission of disease. The flea, the louse, the bedbug, the house fly,
the mosquito, the tick, have all within a few years taken their places
as important transmitters of disease. The fly population may be taken
as the sanitary index of a place. The discovery, too, that insects are
porters of disease has led to a great extension of our knowledge of
their life history. Early in the nineties, when Dr. Thayer and I were
busy with the study of malaria in Baltimore, we began experiments on
the possible transmission of the parasites, and a tramp, who had been
a medical student, offered himself as a subject. Before we began, Dr.
Thayer sought information as to the varieties of mosquitoes known in
America, but sought in vain: there had at that time been no systematic
study. The fundamental study which set us on the track was a
demonstration by Patrick Manson,(3) in 1879, of the association of
filarian disease with the mosquito. Many observations had already
been made, and were made subsequently, on the importance of insects as
intermediary hosts in the animal parasites, but the first really great
scientific demonstration of a widespread infection through insects was
by Theobald Smith, now of Harvard University, in 1889, in a study of
Texas fever of cattle.(4) I well remember the deep impression made upon
me by his original communication, which in completeness, in accuracy of
detail, in Harveian precision and in practical results remains one of
the most brilliant pieces of experimental work ever undertaken. It is
difficult to draw comparisons in pathology; but I think, if a census
were taken among the world's workers on disease, the judgment to be
based on the damage to health and direct mortality, the votes would be
given to malaria as the greatest single destroyer of the human race.
Cholera kills its thousands, plague, in its bad years, its hundreds of
thousands, yellow fever, hookworm disease, pneumonia, tuberculosis,
are all terribly destructive, some only in the tropics, others in more
temperate regions: but malaria is today, as it ever was, a disease to
which the word pandemic is specially applicable. In this country and in
Europe, its ravages have lessened enormously during the past century,
but in the tropics it is everywhere and always present, the greatest
single foe of the white man, and at times and places it assumes the
proportions of a terrible epidemic. In one district of India alone,
during the last four months of 1908, one quarter of the total population
suffered from the disease and there were 400,000 deaths--practically
all from malaria. Today, the control of this terrible scourge is in our
hands, and, as I shall tell you in a few minutes, largely because of
this control, the Panama Canal is being built. No disease illustrates
better the progressive evolution of scientific medicine. It is one of
the oldest of known diseases. The Greeks and Graeco-Romans knew it well.
It seems highly probable, as brought out by the studies of W.H.S. Jones
of Cambridge, that, in part at least, the physical degeneration in
Greece and Rome may have been due to the great increase of this disease.
Its clinical manifestations were well known and admirably described by
the older writers. In the seventeenth century, as I have already told
you, the remarkable discovery was made that the bark of the cinchona
tree was a specific. Between the date of the Countess's recovery in Lima
and the year 1880 a colossal literature on the disease had accumulated.
Literally thousands of workers had studied the various aspects of its
many problems; the literature of this country, particularly of the
Southern States, in the first half of the last century may be said to
be predominantly malarial. Ordinary observation carried on for long
centuries had done as much as was possible. In 1880, a young French army
surgeon, Laveran by name, working in Algiers, found in the microscopic
examination of the blood that there were little bodies in the red blood
corpuscles, amoeboid in character, which he believed to be the germs of
the disease. Very little attention at first was paid to his work, and it
is not surprising. It was the old story of "Wolf, wolf"; there had been
so many supposed "germs" that the profession had become suspicious.
Several years elapsed before Surgeon-General Sternberg called the
attention of the English-speaking world to Laveran's work: it was taken
up actively in Italy, and in America by Councilman, Abbott and by others
among us in Baltimore. The result of these widespread observations
was the confirmation in every respect of Laveran's discovery of the
association with malaria of a protozoan parasite. This was step
number three. Clinical observation, empirical discovery of the cure,
determination of the presence of a parasite. Two other steps followed
rapidly. Another army surgeon, Ronald Ross, working in India, influenced
by the work of Manson, proved that the disease was transmitted by
certain varieties of mosquitoes. Experiments came in to support the
studies in etiology; two of those may be quoted. Mosquitoes which had
bitten malarial patients in Italy were sent to London and there allowed
to bite Mr. Manson, son of Dr. Manson. This gentleman had not lived out
of England, where there is now no acute malaria. He had been a perfectly
healthy, strong man. In a few days following the bites of the infected
mosquitoes, he had a typical attack of malarial fever.

     (3) Journal Linnaean Society, London, 1879, XIV, 304-311.

     (4) Medical News, Philadelphia, 1889, LV, 689-693, and monograph
     with Kilborne, Washington, 1893.

The other experiment, though of a different character, is quite as
convincing. In certain regions about Rome, in the Campania, malaria is
so prevalent that, in the autumn, almost everyone in the district is
attacked, particularly if he is a newcomer. Dr. Sambon and a friend
lived in this district from June 1 to September 1, 1900. The test was
whether they could live in this exceedingly dangerous climate for
the three months without catching malaria, if they used stringent
precautions against the bites of mosquitoes. For this purpose the hut
in which they lived was thoroughly wired, and they slept under netting.
Both of these gentlemen, at the end of the period, had escaped the
disease.

Then came the fifth and final triumph--the prevention of the disease.
The anti-malarial crusade which has been preached by Sir Ronald Ross and
has been carried out successfully on a wholesale scale in Italy and in
parts of India and Africa, has reduced enormously the incidence of
the disease. Professor Celli of Rome, in his lecture room, has an
interesting chart which shows the reduction in the mortality from
malaria in Italy since the preventive measures have been adopted--the
deaths have fallen from above 28,000 in 1888 to below 2000 in 1910.
There is needed a stirring campaign against the disease throughout the
Southern States of this country.

The story of yellow fever illustrates one of the greatest practical
triumphs of scientific medicine; indeed, in view of its far-reaching
commercial consequences, it may range as one of the first achievements
of the race. Ever since the discovery of America, the disease has been
one of its great scourges, permanently endemic in the Spanish Main,
often extending to the Southern States, occasionally into the North, and
not infrequently it has crossed the Atlantic. The records of the British
Army in the West Indies show an appalling death rate, chiefly from this
disease. At Jamaica, for the twenty years ending in 1836, the average
mortality was 101 per thousand, and in certain instances as high as 178.
One of the most dreaded of all infections, the periods of epidemics in
the Southern States have been the occasions of a widespread panic with
complete paralysis of commerce. How appalling the mortality is may be
judged from the outbreak in Philadelphia in 1793, when ten thousand
people died in three months.(5) The epidemics in Spain in the early part
of the nineteenth century were of great severity. A glance through
La Roche's great book(6) on the subject soon gives one an idea of
the enormous importance of the disease in the history of the Southern
States. Havana, ever since its foundation, had been a hotbed of yellow
fever. The best minds of the profession had been attracted to a solution
of the problem, but all in vain. Commission after commission had been
appointed, with negative results; various organisms had been described
as the cause, and there were sad illustrations of the tragedy associated
with investigations undertaken without proper training or proper
technique. By the year 1900, not only had the ground been cleared,
but the work on insect-borne disease by Manson and by Ross had given
observers an important clue. It had repeatedly been suggested that
some relation existed between the bites of mosquitoes and the tropical
fevers, particularly by that remarkable student, Nott of Mobile, and
the French physician, Beauperthuy. But the first to announce clearly the
mosquito theory of the disease was Carlos Finlay of Havana. Early in the
spring of 1900, during the occupation of Cuba by the United States, a
commission appointed by Surgeon-General Sternberg (himself one of the
most energetic students of the disease) undertook fresh investigations.
Dr. Walter Reed, Professor of Bacteriology in the Army Medical School,
was placed in charge: Dr. Carroll of the United States Army, Dr.
Agramonte of Havana and Dr. Jesse W. Lazear were the other members. At
the Johns Hopkins Hospital, we were deeply interested in the work, as
Dr. Walter Reed was a favorite pupil of Professor Welch, a warm friend
of all of us, and a frequent visitor to our laboratories. Dr. Jesse
Lazear, who had been my house physician, had worked with Dr. Thayer and
myself at malaria, and gave up the charge of my clinical laboratory to
join the commission.

     (5) Matthew Carey:  A Short Account of the Malignant Fever,
     Philadelphia, 1793.

     (6) R. La Roche:  Yellow Fever, 2 vols., Philadelphia, 1855.

Many scientific discoveries have afforded brilliant illustrations of
method in research, but in the work of these men one is at a loss to
know which to admire more--the remarkable accuracy and precision of the
experiments, or the heroism of the men--officers and rank and file of
the United States Army; they knew all the time that they were playing
with death, and some of them had to pay the penalty! The demonstration
was successful--beyond peradventure--that yellow fever could be
transmitted by mosquitoes, and equally the negative proposition--that it
could not be transmitted by fomites. An interval of twelve or more days
was found to be necessary after the mosquito has bitten a yellow fever
patient before it is capable of transmitting the infection. Lazear
permitted himself to be bitten by a stray mosquito while conducting his
experiments in the yellow fever hospital. Bitten on the thirteenth, he
sickened on the eighteenth and died on the twenty-fifth of September,
but not until he had succeeded in showing in two instances that
mosquitoes could convey the infection. He added another to the long list
of members of the profession who have laid down their lives in search
of the causes of disease. Of such men as Lazear and of Myers of the
Liverpool Yellow-Fever Commission, Dutton and young Manson, may fitly be
sung from the noblest of American poems the tribute which Lowell paid to
Harvard's sons who fell in the War of Secession:

     Many in sad faith sought for her,
     Many with crossed hands sighed for her;
     But these, our brothers, fought for her,
     At life's dear peril wrought for her,
     So loved her that they died for her.

Fortunately, the commander-in-chief at the time in Cuba was General
Leonard Wood, who had been an army surgeon, and he was the first to
appreciate the importance of the discovery. The sanitation of Havana was
placed in the hands of Dr. Gorgas, and within nine months the city was
cleared of yellow fever, and, with the exception of a slight outbreak
after the withdrawal of the American troops, has since remained free
from a disease which had been its scourge for centuries. As General Wood
remarked, "Reed's discovery has resulted in the saving of more lives
annually than were lost in the Cuban War, and saves the commercial
interest of the world a greater financial loss each year than the
cost of the Cuban War. He came to Cuba at a time when one third of the
officers of my staff died of yellow fever, and we were discouraged at
the failure of our efforts to control it." Following the example of
Havana other centres were attacked, at Vera Cruz and in Brazil, with the
same success, and it is safe to say that now, thanks to the researches
of Reed and his colleagues, with proper measures, no country need fear a
paralyzing outbreak of this once dreaded disease.

The scientific researches in the last two decades of the nineteenth
century made possible the completion of the Panama Canal. The narrow
isthmus separating the two great oceans and joining the two great
continents, has borne for four centuries an evil repute as the White
Man's Grave. Silent upon a peak of Darien, stout Cortez with eagle eye
had gazed on the Pacific. As early as 1520, Saavedra proposed to cut
a canal through the Isthmus. There the first city was founded by the
conquerors of the new world, which still bears the name of Panama.
Spaniards, English and French fought along its coasts; to it the founder
of the Bank of England took his ill-fated colony; Raleigh, Drake, Morgan
the buccaneer, and scores of adventurers seeking gold, found in fever an
enemy stronger than the Spaniard. For years the plague-stricken Isthmus
was abandoned to the negroes and the half-breeds, until in 1849,
stimulated by the gold fever of California, a railway was begun by
the American engineers, Totten and Trautwine, and completed in 1855,
a railway every tie of which cost the life of a man. The dream of
navigators and practical engineers was taken in hand by Ferdinand de
Lesseps in January, 1881. The story of the French Canal Company is a