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ON THE GENESIS OF SPECIES.

ON THE

GENESIS OF SPECIES.

BY
ST. GEORGE MIVART, F.R.S.

London:
MACMILLAN AND CO.
1871.

[_The Right of Translation and Reproduction is reserved._]

LONDON:
R. CLAY, SONS, AND TAYLOR, PRINTERS,
BREAD STREET HILL.

TO

SIR HENRY HOLLAND, BART., M.D.,

F.R.S., D.C.L., ETC. ETC.

MY DEAR SIR HENRY,

In giving myself the pleasure to dedicate, as I now do, this work to you,
it is not my intention to identify you with any views of my own advocated
in it.

I simply avail myself of an opportunity of paying a tribute of esteem and
regard to my earliest scientific friend--the first to encourage me in
pursuing the study of nature.

      I remain,
          MY DEAR SIR HENRY,
              Ever faithfully yours,
                  ST. GEORGE MIVART.

  7, NORTH BANK, REGENT'S PARK,
      _December 8, 1870._

                                                                      {vii}

CONTENTS.

CHAPTER I.

_INTRODUCTORY_

The problem of the genesis of species stated.--Nature of its probable
solution.--Importance of the question.--Position here defended.--Statement
of the DARWINIAN THEORY.--Its applicability to details of geographical
distribution; to rudimentary structures; to homology; to mimicry,
&c.--Consequent utility of the theory.--Its wide acceptance.--Reasons for
this other than, and in addition to, its scientific value. Its
simplicity.--Its bearing on religious questions.--_Odium theologicum_ and
_odium antitheologicum_.--The antagonism supposed by many to exist between
it and theology neither necessary nor universal.--Christian authorities in
favour of evolution.--Mr. Darwin's "Animals and Plants under
Domestication."--Difficulties of the Darwinian theory enumerated ... _Page_
1

CHAPTER II.

_THE INCOMPETENCY OF "NATURAL SELECTION" TO ACCOUNT FOR THE INCIPIENT
STAGES OF USEFUL STRUCTURES._

Mr. Darwin supposes that Natural-Selection acts by slight
variations.--These must be useful at once.--Difficulties as to the giraffe;
as to mimicry; as to the heads of flat-fishes; as to the origin and
constancy of the vertebrate, limbs; as to whalebone; as to the young
kangaroo; as to sea-urchins; as to certain processes of              {viii}
metamorphosis; as to the mammary gland; as to certain ape characters; as to
the rattlesnake and cobra; as to the process of formation of the eye and
ear; as to the fully developed condition of the eye and ear; as to the
voice; as to shell-fish; as to orchids; as to ants.--The necessity for the
simultaneous modification of many individuals.--Summary and conclusion ...
_Page_ 23

CHAPTER III.

_THE CO-EXISTENCE OF CLOSELY SIMILAR STRUCTURES OF DIVERSE ORIGIN._

Chances against concordant variations.--Examples of discordant
ones.--Concordant variations not unlikely on a non-Darwinian evolutionary
hypothesis.--Placental and implacental mammals.--Birds and
reptiles.--Independent origins of similar sense organs.--The ear.--The
eye.--Other coincidences.--Causes besides Natural Selection produce
concordant variations in certain geographical regions.--Causes besides
Natural Selection produce concordant variations in certain zoological and
botanical groups.--There are homologous parts not genetically
related.--Harmony in respect of the organic and inorganic worlds.--Summary
and conclusion ... _Page_ 63

CHAPTER IV.

_MINUTE AND GRADUAL MODIFICATIONS._

There are difficulties as to minute modifications, even if not
fortuitous.--Examples of sudden and considerable modifications of different
kinds.--Professor Owen's view.--Mr. Wallace.--Professor Huxley.--Objections
to sudden changes.--Labyrinthodont.--Potto.--Cetacea.--As to origin of
bird's wing.--Tendrils of climbing plants.--Animals once supposed to be
connecting links.--Early specialization of
structure.--Macrauchenia.--Glyptodon.--Sabre-toothed tiger.--Conclusion ...
_Page_ 97

                                                                       {ix}
CHAPTER V.

_AS TO SPECIFIC STABILITY._

What is meant by the phrase "specific stability;" such stability to be
expected _a priori_, or else considerable changes at once.--Rapidly
increasing difficulty of intensifying race characters; alleged causes of
this phenomenon; probably an internal cause co-operates.--A certain
definiteness in variations.--Mr. Darwin admits the principle of specific
stability in certain cases of unequal variability.--The goose.--The
peacock.--The guinea fowl.--Exceptional causes of variation under
domestication.--Alleged tendency to reversion.--Instances.--Sterility of
hybrids.--Prepotency of pollen of same species, but of different
race.--Mortality in young gallinaceous hybrids.--A bar to intermixture
exists somewhere.--Guinea-pigs.--Summary and conclusion ... _Page_ 113

CHAPTER VI.

_SPECIES AND TIME._

Two relations of species to time.--No evidence of past existence of
minutely intermediate forms when such might be expected _a priori_.--Bats,
Pterodactyles, Dinosauria, and Birds.--Ichthyosauria, Chelonia, and
Anoura.--Horse ancestry.--Labyrinthodonts and Trilobites.--Two subdivisions
of the second relation of species to time.--Sir William Thomson's
views.--Probable period required for ultimate specific evolution from
primitive ancestral forms.---Geometrical increase of time required for
rapidly multiplying increase of structural differences.--Proboscis
monkey.--Time required for deposition of strata necessary for Darwinian
evolution.--High organization of Silurian forms of life.--Absence of
fossils in oldest rocks.--Summary and conclusion ... _Page_ 128

CHAPTER VII.

_SPECIES AND SPACE._

The geographical distribution of animals presents difficulties.--These not
insurmountable in themselves; harmonize with other
difficulties.--Fresh-water fishes.--Forms common to Africa and India; to
Africa and South America; to China and Australia; to North America and  {x}
China; to New Zealand and South America; to South America and Tasmania; to
South America and Australia.--Pleurodont lizards.--Insectivorous
mammals.--Similarity of European and South American frogs.--Analogy between
European salmon and fishes of New Zealand, &c.--An ancient Antarctic
continent probable.--Other modes of accounting for facts of
distribution.--Independent origin of closely similar forms.--Conclusion ...
_Page_ 144

CHAPTER VIII.

_HOMOLOGIES._

Animals made up of parts mutually related in various ways.--What homology
is.--Its various kinds.--Serial homology.--Lateral homology.--Vertical
homology.--Mr. Herbert Spencer's explanations.--An internal power
necessary, as shown by facts of comparative anatomy.---Of teratology.--M.
St. Hilaire.--Professor Burt Wilder.--Foot-wings.--Facts of pathology.--Mr.
James Paget.--Dr. William Budd.--The existence of such an internal power of
individual development diminishes the improbability of an analogous law of
specific origination ... _Page_ 155

CHAPTER IX.

_EVOLUTION AND ETHICS._

The origin of morals an inquiry not foreign to the subject of this
book.--Modern utilitarian view as to that origin.--Mr. Darwin's speculation
as to the origin of the abhorrence of incest.--Cause assigned by him
insufficient.--Care of the aged and infirm opposed by "Natural Selection;"
also self-abnegation and asceticism.--Distinctness of the ideas right and
useful.--Mr. John Stuart Mill.--Insufficiency of "Natural Selection" to
account for the origin of the distinction between duty and
profit.--Distinction of moral acts into material and formal.--No ground{xi}
for believing that formal morality exists in brutes.--Evidence that it does
exist in savages.--Facility with which savages may be
misunderstood.--Objections as to diversity of customs.--Mr. Button's review
of Mr. Herbert Spencer.--Anticipatory character of morals.--Sir John
Lubbock's explanation.--Summary and conclusion ... _Page_ 188

CHAPTER X.

_PANGENESIS._

A provisional hypothesis supplementing "Natural Selection."--Statement of
the hypothesis.--Difficulty as to multitude of gemmules.--As to certain
modes of reproduction.--As to formations without the requisite
gemmules.--Mr. Lewes and Professor Delpino.--Difficulty as to developmental
force of gemmules.--As to their spontaneous fission.--Pangenesis and
Vitalism.--Paradoxical reality.--Pangenesis scarcely superior to anterior
hypotheses.--Buffon.--Owen.--Herbert Spencer.--Gemmules as mysterious as
"physiological units."--Conclusion ... _Page_ 208

CHAPTER XI.

_SPECIFIC GENESIS._

Review of the statements and arguments of preceding chapters.--Cumulative
argument against predominant action of "Natural Selection."--Whether
anything positive as well as negative can be enunciated.--Constancy of laws
of nature does not necessarily imply constancy of specific
evolution.--Possible exceptional stability of existing epoch.--Probability
that an internal cause of change exists.--Innate powers somewhere must be
accepted.--Symbolism of molecular action under vibrating impulses.
Professor Owen's statement.--Statement of the Author's view.--It avoids the
difficulties which oppose "Natural Selection."--It harmonizes apparently
conflicting conceptions.--Summary and conclusion ... _Page_ 220 [Page xii]

CHAPTER XII.

_THEOLOGY AND EVOLUTION._

Prejudiced opinions on the subject.--"Creation" sometimes denied from
prejudice.--The unknowable.--Mr. Herbert Spencer's objections to theism; to
creation.--Meanings of term "creation."--Confusion from not distinguishing
between "primary" and "derivative" creation.--Mr. Darwin's
objections.--Bearing of Christianity on evolution.--Supposed opposition,
the result of a misconception.--Theological authority not opposed to
evolution.--St. Augustin.--St. Thomas Aquinas.--Certain consequences of
want of flexibility of mind.--Reason and imagination.--The first cause and
demonstration.--Parallel between Christianity and natural theology.--What
evolution of species is.--Professor Agassiz.--Innate powers must be
recognized.--Bearing of evolution on religious belief.--Professor
Huxley.--Professor Owen.--Mr. Wallace.--Mr. Darwin.--_A priori_ conception
of Divine action.--Origin of man.--Absolute creation and dogma.--Mr.
Wallace's view.--A supernatural origin for man's body not necessary.--Two
orders of being in man.--Two modes of origin.--Harmony of the physical,
hyperphysical, and supernatural.--Reconciliation of science and religion as
regards evolution.--Conclusion ... _Page_ 243

INDEX ... _Page_ 289

                                                                     {xiii}
LIST OF ILLUSTRATIONS.

Leaf Butterfly in flight and repose (_from Mr. A. Wallace's "Malay
Archipelago"_) ... 31

Walking-Leaf Insect ... 35

Pleuronectidæ, with the peculiarly placed eye in different positions (_from
Dr. Traquair's paper in Linn. Soc. Trans., 1865_) ... 37, 166

Mouth of Whale (_from Professor Owen's "Odontography"_) ... 40

Four plates of Baleen seen obliquely from within (_from Professor Owen's
"Odontography"_) ... 41

Dugong ... 41, 175

Echinus or Sea Urchin ... 43, 167

Pedicellariæ of Echinus very much enlarged ... 44

Rattlesnake ... 49

Cobra (_from Sir Andrew Smith's "Southern Africa"_) ... 50

Wingbones of Pterodactyle, Bat, and Bird (_from Mr. Andrew Murray's
"Geographical Distribution of Mammals"_) ... 64, 130, 157

Skeleton of Flying-Dragon ... 65, 158

Centipede (_from a specimen in the Museum of the Royal College of
Surgeons_) ... 66, 159

Teeth of Urotrichus and Perameles ... 68

The Archeopteryx (_from Professor Owen's "Anatomy of Vertebrata"_) ... 73,
132

                                                                      {xiv}
Cuttle-Fish ... 75, 141

Skeleton of Ichthyosaurus ... 78, 107, 132, 177

Cytheridea Torosa (_from Messrs. Brady and Robertson's paper in Ann. and
Mag. of Nat. Hist., 1870_) ... 79

A Polyzoon, with Bird's-head processes ... 80

Bird's-head processes greatly enlarged ... 81

Antechimis Minutissimus and Mus Delicatulus (_from Mr. Andrew Murray's
"Geographical Distribution of Mammals"_) ... 82

Outlines of Wings of Butterflies of Celebes compared with those of allied
species elsewhere ... 86

Great Shielded Grasshopper ... 89

The Six-shafted Bird of Paradise ... 90

The Long-tailed Bird of Paradise ... 91

The Red Bird of Paradise ... 92

Horned Flies ... 93

The Magnificent Bird of Paradise ... 93

_(The above seven figures are from Mr. A. Wallace's "Malay Archipelago"_)

Much enlarged horizontal Section of the Tooth of a Labyrinthodon (_from
Professor Owen's "Odontography"_) ... 104

Hand of the Potto (_from life_) ... 105

Skeleton of Plesiosaurus ... 106, 133

The Aye-Aye (_from Trans, of Zool. Soc._) ... 108

Dentition of Sabre-toothed Tiger (_from Professor Owen's "Odontography"_)
... 110

Trilobite ... 135, 171

Inner side of Lower Jaw of Pleurodont Lizard (_from Professor Owen's
"Odontography"_) ... 148

Solenodon (_from Berlin Trans._) ... 149

Tarsal Bones of Galago and Cheirogaleus (_from Proc. Zool. Soc._) ... 159

Squilla ... 160

Parts of the Skeleton of the Lobster ... 161 [Page xv]

Spine of Galago Allenii (_from Proc. Zool. Soc._) ... 162

Vertebrae of Axolotl (_from Proc. Zool. Soc._) ... 165

Annelid undergoing spontaneous fission ... 169, 211

Aard-Vark (_Orycteropus capensis_) ... 174

Pangolin (_Manis_) ... 175

Skeleton of Manus and Pes of a Tailed Batrachian (_from Professor
Gegenbaur's "Tarsus and Carpus"_) ... 178

Flexor Muscles of Hand of Nycticetus (_from Proc. Zool. Soc._) ... 180

The Fibres of Corti ... 279

                                                                        {1}

THE GENESIS OF SPECIES.

CHAPTER I.

_INTRODUCTORY._

    The problem of the genesis of species stated.--Nature of its probable
    solution.--Importance of the question.--Position here
    defended.--Statement of the DARWINIAN THEORY.--Its applicability to
    details of geographical distribution; to rudimentary structures; to
    homology; to mimicry, &c.--Consequent utility of the theory.--Its wide
    acceptance.--Reasons for this, other than, and in addition to, its
    scientific value.--Its simplicity.--Its bearing on religious
    questions.--_Odium theologicum_ and _odium antitheologicum_.--The
    antagonism supposed by many to exist between it and theology neither
    necessary nor universal.--Christian authorities in favour of
    evolution.--Mr. Darwin's "Animals and Plants under
    Domestication."--Difficulties of the Darwinian theory enumerated.

The great problem which has so long exercised the minds of naturalists,
namely, that concerning the origin of different kinds of animals and
plants, seems at last to be fairly on the road to receive--perhaps at no
very distant future--as satisfactory a solution as it can well have.

But the problem presents peculiar difficulties. The birth of a "species"
has often been compared with that of an "individual." The origin, however,
of even an individual animal or plant (that which determines an embryo to
evolve itself,--as, _e.g._, a spider rather than a beetle, a rose-plant {2}
rather than a pear) is shrouded in obscurity. _A fortiori_ must this be the
case with the origin of a "species."

Moreover, the analogy between a "species" and an "individual" is a very
incomplete one. The word "individual" denotes a concrete whole with a real,
separate, and distinct existence. The word "species," on the other hand,
denotes a peculiar congeries of characters, innate powers and qualities,
and a certain nature realized indeed in individuals, but having no separate
existence, except ideally as a thought in some mind.

Thus the birth of a "species" can only be compared metaphorically, and very
imperfectly, with that of an "individual."

Individuals as _individuals_, actually and directly produce and bring forth
other individuals; but no "congeries of characters" no "common nature" _as
such_, can directly bring forth another "common nature," because, _per se_,
it has no existence (other than ideal) apart from the individuals in which
it is manifested.

The problem then is, "by what combination of natural laws does a new
'common nature' appear upon the scene of realized existence?" _i.e._ how is
an individual embodying such new characters produced?

For the approximation we have of late made towards the solution of this
problem, we are mainly indebted to the invaluable labours and active brains
of Charles Darwin and Alfred Wallace.

Nevertheless, important as has been the impulse and direction given by
those writers to both our observations and speculations, the solution will
not (if the views here advocated are correct) ultimately present that
aspect and character with which it has issued from the hands of those
writers.

Neither, most certainly, will that solution agree in appearance or
substance with the more or less crude conceptions which have been put forth
by most of the opponents of Messrs. Darwin and Wallace. [Page 3]

Rather, judging from the more recent manifestations of thought on opposite
sides, we may expect the development of some _tertium quid_--the resultant
of forces coming from different quarters, and not coinciding in direction
with any one of them.

As error is almost always partial truth, and so consists in the
exaggeration or distortion of one verity by the suppression of another
which qualifies and modifies the former, we may hope, by the synthesis of
the truths contended for by various advocates, to arrive at the one
conciliating reality.

Signs of this conciliation are not wanting: opposite scientific views,
opposite philosophical conceptions, and opposite religious beliefs, are
rapidly tending by their vigorous conflict to evolve such a systematic and
comprehensive view of the genesis of species as will completely harmonize
with the teachings of science, philosophy, and religion.

To endeavour to add one stone to this temple of concord, to try and remove
a few of the misconceptions and mutual misunderstandings which oppose
harmonious action, is the aim and endeavour of the present work. This aim
it is hoped to attain, not by shirking difficulties, but analysing them,
and by endeavouring to dig down to the common root which supports and
unites diverging stems of truth.

It cannot but be a gain when the labourers in the three fields above
mentioned, namely, science, philosophy, and religion, shall fully recognize
this harmony. Then the energy too often spent in futile controversy, or
withheld through prejudice, may be profitably and reciprocally exercised
for the mutual benefit of all.

Remarkable is the rapidity with which an interest in the question of
specific origination has spread. But a few years ago it scarcely occupied
the minds of any but naturalists. Then the crude theory put forth by
Lamarck, and by his English interpreter the author of the "Vestiges of
Creation," had rather discredited than helped on a belief in organic
evolution--a belief, that is, in new kinds being produced from older    {4}
ones by the ordinary and constant operation of natural laws. Now, however,
this belief is widely diffused. Indeed, there are few drawing-rooms where
it is not the subject of occasional discussion, and artisans and schoolboys
have their views as to the permanence of organic forms. Moreover, the
reception of this doctrine tends actually, though by no means necessarily,
to be accompanied by certain beliefs with regard to quite distinct and very
momentous subject-matter. So that the question of the "Genesis of Species"
is not only one of great interest, but also of much importance.

But though the calm and thorough consideration of this matter is at the
present moment exceedingly desirable, yet the actual importance of the
question itself as to its consequences in the domain of theology has been
strangely exaggerated by many, both of its opponents and supporters. This
is especially the case with that form of the evolution theory which is
associated with the name of Mr. Darwin; and yet neither the refutation nor
the demonstration of that doctrine would be necessarily accompanied by the
results which are hoped for by one party and dreaded by another.

The general theory of evolution has indeed for some time past steadily
gained ground, and it may be safely predicted that the number of facts
which can be brought forward in its support will, in a few years, be vastly
augmented. But the prevalence of this theory need alarm no one, for it is,
without any doubt, perfectly consistent with strictest and most orthodox
Christian theology. Moreover, it is not altogether without obscurities, and
cannot yet be considered as fully demonstrated.

The special Darwinian hypothesis, however, is beset with certain scientific
difficulties, which must by no means be ignored, and some of which, I
venture to think, are absolutely insuperable. What Darwinism or "Natural
Selection" is, will be shortly explained; but before doing so, I think  {5}
it well to state the object of this book, and the view taken up and
defended in it. It is its object to maintain the position that "Natural
Selection" acts, and indeed must act, but that still, in order that we may
be able to account for the production of known kinds of animals and plants,
it requires to be supplemented by the action of some other natural law or
laws as yet undiscovered.[1] Also, that the consequences which have been
drawn from Evolution, whether exclusively Darwinian or not, to the
prejudice of religion, by no means follow from it, and are in fact
illegitimate.

The Darwinian theory of "Natural Selection" may be shortly stated
thus:[2]--

Every kind of animal and plant tends to increase in numbers in a
geometrical progression.

Every kind of animal and plant transmits a general likeness, with
individual differences, to its offspring.

Every individual may present minute variations of any kind and in any
direction.

Past time has been practically infinite.

Every individual has to endure a very severe struggle for existence, owing
to the tendency to geometrical increase of all kinds of animals and plants,
while the total animal and vegetable population (man and his agency
excepted) remains almost stationary.

Thus, every variation of a kind tending to save the life of the individual
possessing it, or to enable it more surely to propagate its kind, will in
the long run be preserved, and will transmit its favourable peculiarity to
some of its offspring, which peculiarity will thus become intensified   {6}
till it reaches the maximum degree of utility. On the other hand,
individuals presenting unfavourable peculiarities will be ruthlessly
destroyed. The action of this law of Natural Selection may thus be well
represented by the convenient expression "survival of the fittest."[3]

Now this conception of Mr. Darwin's is perhaps the most interesting theory,
in relation to natural science, which has been promulgated during the
present century. Remarkable, indeed, is the way in which it groups together
such a vast and varied series of biological[4] facts, and even paradoxes,
which it appears more or less clearly to explain, as the following
instances will show. By this theory of "Natural Selection," light is thrown
on the more singular facts relating to the geographical distribution of
animals and plants; for example, on the resemblance between the past and
present inhabitants of different parts of the earth's surface. Thus in
Australia remains have been found of creatures closely allied to kangaroos
and other kinds of pouched beasts, which in the present day exist nowhere
but in the Australian region. Similarly in South America, and nowhere else,
are found sloths and armadillos, and in that same part of the world have
been discovered bones of animals different indeed from existing sloths and
armadillos, but yet much more nearly related to them than to any other
kinds whatever. Such coincidences between the existing and antecedent
geographical distribution of forms are numerous. Again, "Natural Selection"
serves to explain the circumstance that often in adjacent islands we find
animals closely resembling, and appearing to represent, each other; while
if certain of these islands show signs (by depth of surrounding sea or what
not) of more ancient separation, the animals inhabiting them exhibit a  {7}
corresponding divergence.[5] The explanation consists in representing the
forms inhabiting the islands as being the modified descendants of a common
stock, the modification being greatest where the separation has been the
most prolonged.

"Rudimentary structures" also receive an explanation by means of this
theory. These structures are parts which are apparently functionless and
useless where they occur, but which represent similar parts of large size
and functional importance in other animals. Examples of such "rudimentary
structures" are the foetal teeth of whales, and of the front part of the
jaw of ruminating quadrupeds. These foetal structures are minute in size,
and never cut the gum, but are reabsorbed without ever coming into use,
while no other teeth succeed them or represent them in the adult condition
of those animals. The mammary glands of all male beasts constitute another
example, as also does the wing of the apteryx--a New Zealand bird utterly
incapable of flight, and with the wing in a quite rudimentary condition
(whence the name of the animal). Yet this rudimentary wing contains bones
which are miniature representatives of the ordinary wing-bones of birds of
flight. Now, the presence of these useless bones and teeth is explained if
they may be considered as actually being the inherited diminished
representatives of parts of large size and functional importance in the
remote ancestors of these various animals.

Again, the singular facts of "homology" are capable of a similar
explanation. "Homology" is the name applied to the investigation of those
profound resemblances which have so often been found to underlie
superficial differences between animals of very different form and habit.
Thus man, the horse, the whale, and the bat, all have the pectoral limb,
whether it be the arm, or fore-leg, or paddle, or wing, formed on
essentially the same type, though the number and proportion of parts may{8}
more or less differ. Again, the butterfly and the shrimp, different as they
are in appearance and mode of life, are yet constructed on the same common
plan, of which they constitute diverging manifestations. No _a priori_
reason is conceivable why such similarities should be necessary, but they
are readily explicable on the assumption of a genetic relationship and
affinity between the animals in question, assuming, that is, that they are
the modified descendants of some ancient form--their common ancestor.

That remarkable series of changes which animals undergo before they attain
their adult condition, which is called their process of development, and
during which they more or less closely resemble other animals during the
early stages of the same process, has also great light thrown on it from
the same source. The question as to the singularly complex resemblances
borne by every adult animal and plant to a certain number of other animals
and plants--resemblances by means of which the adopted zoological and
botanical systems of classification have been possible--finds its solution
in a similar manner, classification becoming the expression of a
genealogical relationship. Finally, by this theory--and as yet by this
alone--can any explanation be given of that extraordinary phenomenon which
is metaphorically termed _mimicry_. Mimicry is a close and striking, yet
superficial resemblance borne by some animal or plant to some other,
perhaps very different, animal or plant. The "walking leaf" (an insect
belonging to the grasshopper and cricket order) is a well-known and
conspicuous instance of the assumption by an animal of the appearance of a
vegetable structure (see illustration on p. 35); and the bee, fly, and
spider orchids are familiar examples of a converse resemblance. Birds,
butterflies, reptiles, and even fish, seem to bear in certain instances a
similarly striking resemblance to other birds, butterflies, reptiles, and
fish, of altogether distinct kinds. The explanation of this matter which
"Natural Selection" offers, as to animals, is that certain varieties of {9}
one kind have found exemption from persecution in consequence of an
accidental resemblance which such varieties have exhibited to animals of
another kind, or to plants; and that they were thus preserved, and the
degree of resemblance was continually augmented in their descendants. As to
plants, the explanation offered by this theory might perhaps be that
varieties of plants which presented a certain superficial resemblance in
their flowers to insects, have thereby been helped to propagate their kind,
the visit of certain insects being useful or indispensable to the
fertilization of many flowers.

We have thus a whole series of important facts which "Natural Selection"
helps us to understand and co-ordinate. And not only are all these diverse
facts strung together, as it were, by the theory in question; not only does
it explain the development of the complex instincts of the beaver, the
cuckoo, the bee, and the ant, as also the dazzling brilliancy of the
humming-bird, the glowing tail and neck of the peacock, and the melody of
the nightingale; the perfume of the rose and the violet, the brilliancy of
the tulip and the sweetness of the nectar of flowers; not only does it help
us to understand all these, but serves as a basis of future research and of
inference from the known to the unknown, and it guides the investigator to
the discovery of new facts which, when ascertained, it seems also able to
co-ordinate.[6] Nay, "Natural Selection" seems capable of application not
only to the building up of the smallest and most insignificant organisms,
but even of extension beyond the biological domain altogether, so as
possibly to have relation to the stable equilibrium of the solar system{10}
itself, and even of the whole sidereal universe. Thus, whether this theory
be true or false, all lovers of natural science should acknowledge a deep
debt of gratitude to Messrs. Darwin and Wallace, on account of its
practical utility. But the utility of a theory by no means implies its
truth. What do we not owe, for example, to the labours of the Alchemists?
The emission theory of light, again, has been pregnant with valuable
results, as still is the Atomic theory, and others which will readily
suggest themselves.

With regard to Mr. Darwin (with whose name, on account of the noble
self-abnegation of Mr. Wallace, the theory is in general exclusively
associated), his friends may heartily congratulate him on the fact that he
is one of the few exceptions to the rule respecting the non-appreciation of
a prophet in his own country. It would be difficult to name another living
labourer in the field of physical science who has excited an interest so
widespread, and given rise to so much praise, gathering round him, as he
has done, a chorus of more or less completely acquiescing disciples,
themselves masters in science, and each the representative of a crowd of
enthusiastic followers.

Such is the Darwinian theory of "Natural Selection," such are the more
remarkable facts which it is potent to explain, and such is the reception
it has met with in the world. A few words now as to the reasons for the
very widespread interest it has awakened, and the keenness with which the
theory has been both advocated and combated.

The important bearing it has on such an extensive range of scientific
facts, its utility, and the vast knowledge and great ingenuity of its
promulgator, are enough to account for the heartiness of its reception by
those learned in natural history. But quite other causes have concurred to
produce the general and higher degree of interest felt in the theory beside
the readiness with which it harmonizes with biological facts. These latter
could only be appreciated by physiologists, zoologists, and botanists;
whereas the Darwinian theory, so novel and so startling, has found a   {11}
cloud of advocates and opponents beyond and outside the world of physical
science.

In the first place, it was inevitable that a great crowd of half-educated
men and shallow thinkers should accept with eagerness the theory of
"Natural Selection," or rather what they think to be such (for few things
are more remarkable than the way in which it has been misunderstood), on
account of a certain characteristic it has in common with other theories;
which should not be mentioned in the same breath with it, except, as now,
with the accompaniment of protest and apology. We refer to its remarkable
simplicity, and the ready way in which phenomena the most complex appear
explicable by a cause for the comprehension of which laborious and
persevering efforts are not required, but which may be represented by the
simple phrase "survival of the fittest." With nothing more than this, can,
on the Darwinian theory, all the most intricate facts of distribution and
affinity, form, and colour, be accounted for; as well the most complex
instincts and the most admirable adjustments, such as those of the human
eye and ear. It is in great measure then, owing to this supposed
simplicity, and to a belief in its being yet easier and more simple than it
is, that Darwinism, however imperfectly understood, has become a subject
for general conversation, and has been able thus widely to increase a
certain knowledge of biological matters; and this excitation of interest in
quarters where otherwise it would have been entirely wanting, is an
additional motive for gratitude on the part of naturalists to the authors
of the new theory. At the same time it must be admitted that a similar
"simplicity"--the apparently easy explanation of complex phenomena--also
constitutes the charm of such matters as hydropathy and phrenology, in the
eyes of the unlearned or half-educated public. It is indeed _the_ charm of
all those seeming "short cuts" to knowledge, by which the labour of
mastering scientific details is spared to those who yet believe that   {12}
without such labour they can attain all the most valuable results of
scientific research. It is not, of course, for a moment meant to imply that
its "simplicity" tells at all against "Natural Selection," but only that
the actual or supposed possession of that quality is a strong reason for
the wide and somewhat hasty acceptance of the theory, whether it be true or
not.

In the second place, it was inevitable that a theory appearing to have very
grave relations with questions of the last importance and interest to man,
that is, with questions of religious belief, should call up an army of
assailants and defenders. Nor have the supporters of the theory much
reason, in many cases, to blame the more or less unskilful and hasty
attacks of adversaries, seeing that those attacks have been in great part
due to the unskilful and perverse advocacy of the cause on the part of some
of its adherents. If the _odium theologicum_ has inspired some of its
opponents, it is undeniable that the _odium antitheologicum_ has possessed
not a few of its supporters. It is true (and in appreciating some of Mr.
Darwin's expressions it should never be forgotten) that the theory has been
both at its first promulgation and since vehemently attacked and denounced
as unchristian, nay, as necessarily atheistic; but it is not less true that
it has been made use of as a weapon of offence by irreligious writers, and
has been again and again, especially in continental Europe, thrown, as it
were, in the face of believers, with sneers and contumely. When we
recollect the warmth with which what he thought was Darwinism was advocated
by such a writer as Professor Vogt, one cause of his zeal was not far to
seek--a zeal, by the way, certainly not "according to knowledge;" for few
conceptions could have been more conflicting with true Darwinism than the
theory he formerly maintained, but has since abandoned, viz. that the men
of the Old World were descended from African and Asiatic apes, while,
similarly, the American apes were the progenitors of the human beings of
the New World. The cause of this palpable error in a too eager disciple{13}
one might hope was not anxiety to snatch up all or any arms available
against Christianity, were it not for the tone unhappily adopted by this
author. But it is unfortunately quite impossible to mistake his meaning and
intention, for he is a writer whose offensiveness is gross, while it is
sometimes almost surpassed by an amazing shallowness. Of course, as might
fully be expected, he adopts and reproduces the absurdly trivial objections
to absolute morality drawn from differences in national customs.[7] And he
seems to have as little conception of the distinction between "formally"
moral actions and those which are only "materially" moral, as of that
between the _verbum mentale_ and the _verbum oris_. As an example of his
onesidedness, it may be remarked that he compares the skulls of the
American monkeys (_Cebus apella_ and _C. albifrons_) with the intention of
showing that man is of several distinct species, because skulls of
different men are less alike than are those of these two monkeys; and he
does this regardless of how the skulls of domestic animals (with which it
is far more legitimate to compare races of men than with wild kinds),
_e.g._ of different dogs or pigeons, tell precisely in the opposite
direction. Regardless also of the fact that perhaps no genus of monkeys is
in a more unsatisfactory state as to the determination of its different
kinds than the genus chosen by him for illustration. This is so much the
case that J. A. Wagner (in his supplement to Schreber's great work on
Beasts) at first included all the kinds in a single species.

As to the strength of his prejudice and his regretable coarseness, one
quotation will be enough to display both. Speaking of certain early
Christian missionaries, he says,[8] "It is not so very improbable that the
new religion, before which the flourishing Roman civilization relapsed into
a state of barbarism, should have been introduced by people in whose   {14}
skulls the anatomist finds simious characters so well developed, and in
which the phrenologist finds the organ of veneration so much enlarged. I
shall, in the meanwhile, call these simious narrow skulls of Switzerland
'Apostle skulls,' as I imagine that in life they must have resembled the
type of Peter, the Apostle, as represented in Byzantine-Nazarene art."

In face of such a spirit, can it be wondered at that disputants have grown
warm? Moreover, in estimating the vehemence of the opposition which has
been offered, it should be borne in mind that the views defended by
religious writers are, or should be, all-important in their eyes. They
could not be expected to view with equanimity the destruction in many minds
of "theology, natural and revealed, psychology, and metaphysics;" nor to
weigh with calm and frigid impartiality arguments which seemed to them to
be fraught with results of the highest moment to mankind, and, therefore,
imposing on their consciences strenuous opposition as a first duty. Cool
judicial impartiality in them would have been a sign perhaps of
intellectual gifts, but also of a more important deficiency of generous
emotion.

It is easy to complain of the onesidedness of many of those who oppose
Darwinism in the interest of orthodoxy; but not at all less patent is the
intolerance and narrow-mindedness of some of those who advocate it,
avowedly or covertly, in the interest of heterodoxy. This hastiness of
rejection or acceptance, determined by ulterior consequences believed to
attach to "Natural Selection," is unfortunately in part to be accounted for
by some expressions and a certain tone to be found in Mr. Darwin's
writings. That his expressions, however, are not always to be construed
literally is manifest. His frequent use metaphorically of the expressions,
"contrivance," for example, and "purpose," has elicited, from the Duke of
Argyll and others, criticisms which fail to tell against their         {15}
opponent, because such expressions are, in Mr. Darwin's writings, merely
figurative--metaphors, and nothing more.

It may be hoped, then, that a similar looseness of expression will account
for passages of a directly opposite tendency to that of his theistic
metaphors.

Moreover, it must not be forgotten that he frequently uses that absolutely
theological term, "the Creator," and that he has retained in all the
editions of his "Origin of Species" an expression which has been much
criticised. He speaks "of life, with its several powers, having been
originally breathed by the Creator into a few forms, or into one."[9] This
is merely mentioned in justice to Mr. Darwin, and by no means because it is
a position which this book is intended to support. For, from Mr. Darwin's
usual mode of speaking, it appears that by such divine action he means a
supernatural intervention, whereas it is here contended that throughout the
whole process of physical evolution--the first manifestation of life
included--_supernatural_ action is assuredly not to be looked for.

Again, in justice to Mr. Darwin, it may be observed that he is addressing
the general public, and opposing the ordinary and common objections of
popular religionists, who have inveighed against "Evolution" and "Natural
Selection" as atheistic, impious, and directly conflicting with the dogma
of creation.

Still, in so important a matter, it is to be regretted that he did not take
the trouble to distinguish between such merely popular views and those
which repose upon some more venerable authority. Mr. John Stuart Mill has
replied to similar critics, and shown that the assertion that his
philosophy is irreconcilable with theism is unfounded; and it would have
been better if Mr. Darwin had dealt in the same manner with some of his
assailants, and shown the futility of certain of their objections when {16}
viewed from a more elevated religious standpoint. Instead of so doing, he
seems to adopt the narrowest notions of his opponents, and, far from
endeavouring to expand them, appears to wish to endorse them, and to lend
to them the weight of his authority. It is thus that Mr. Darwin seems to
admit and assume that the idea of "creation" necessitates a belief in an
interference with, or dispensation of, natural laws, and that "creation"
must be accompanied by arbitrary and unorderly phenomena. None but the
crudest conceptions are placed by him to the credit of supporters of the
dogma of creation, and it is constantly asserted that they, to be
consistent, must offer "creative fiats" as explanations of physical
phenomena, and be guilty of numerous other such absurdities. It is
impossible, therefore, to acquit Mr. Darwin of at least a certain
carelessness in this matter; and the result is, he has the appearance of
opposing ideas which he gives no clear evidence of having ever fully
appreciated. He is far from being alone in this, and perhaps merely takes
up and reiterates, without much consideration, assertions previously
assumed by others. Nothing could be further from Mr. Darwin's mind than
any, however small, intentional misrepresentation; and it is therefore the
more unfortunate that he should not have shown any appreciation of a
position opposed to his own other than that gross and crude one which he
combats so superfluously--that he should appear, even for a moment, to be
one of those, of whom there are far too many, who first misrepresent their
adversary's view, and then elaborately refute it; who, in fact, erect a
doll utterly incapable of self-defence and then, with a flourish of
trumpets and many vigorous strokes, overthrow the helpless dummy they had
previously raised.

This is what many do who more or less distinctly oppose theism in the
interests, as they believe, of physical science; and they often represent,
amongst other things, a gross and narrow anthropomorphism as the necessary
consequence of views opposed to those which they themselves advocate.  {17}
Mr. Darwin and others may perhaps be excused if they have not devoted much
time to the study of Christian philosophy; but they have no right to assume
or accept, without careful examination, as an unquestioned fact, that in
that philosophy there is a necessary antagonism between the two ideas,
"creation" and "evolution," as applied to organic forms.

It is notorious and patent to all who choose to seek, that many
distinguished Christian thinkers have accepted and do accept both ideas,
_i.e._ both "creation" and "evolution."

As much as ten years ago, an eminently Christian writer observed: "The
creationist theory does not necessitate the perpetual search after
manifestations of miraculous powers and perpetual 'catastrophes.' Creation
is not a miraculous interference with the laws of nature, but the very
institution of those laws. Law and regularity, not arbitrary intervention,
was the patristic ideal of creation. With this notion, they admitted
without difficulty the most surprising origin of living creatures, provided
it took place by _law_. They held that when God said, 'Let the waters
produce,' 'Let the earth produce,' He conferred forces on the elements of
earth and water, which enabled them naturally to produce the various
species of organic beings. This power, they thought, remains attached to
the elements throughout all time."[10] The same writer quotes St. Augustine
and St. Thomas Aquinas, to the effect that, "in the institution of nature
we do not look for miracles, but for the laws of nature."[11] And, again,
St. Basil,[12] speaks of the continued operation of natural laws in the
production of all organisms. [Page 18]

So much for writers of early and mediæval times. As to the present day, the
Author can confidently affirm that there are many as well versed in
theology as Mr. Darwin is in his own department of natural knowledge, who
would not be disturbed by the thorough demonstration of his theory. Nay,
they would not even be in the least painfully affected at witnessing the
generation of animals of complex organization by the skilful artificial
arrangement of natural forces, and the production, in the future, of a
fish, by means analogous to those by which we now produce urea.

And this because they know that the possibility of such phenomena, though
by no means actually foreseen, has yet been fully provided for in the old
philosophy centuries before Darwin, or even before Bacon, and that their
place in the system can be at once assigned them without even disturbing
its order or marring its harmony.

Moreover, the old tradition in this respect has never been abandoned,
however much it may have been ignored or neglected by some modern writers.
In proof of this it may be observed that perhaps no post-mediæval
theologian has a wider reception amongst Christians throughout the world
than Suarez, who has a separate section[13] in opposition to those who
maintain the distinct creation of the various kinds--or substantial
forms--of organic life.

But the consideration of this matter must be deferred for the present, and
the question of evolution, whether Darwinian or other, be first gone into.
It is proposed, after that has been done, to return to this subject (here
merely alluded to), and to consider at some length the bearing of
"Evolution," whether Darwinian or non-Darwinian, upon "Creation and
Theism."

Now we will revert simply to the consideration of the theory of "Natural
Selection" itself.

                                                                       {19}
Whatever may have hitherto been the amount of acceptance that this theory
has met with, all, I think, anticipated that the appearance of Mr. Darwin's
large and careful work on "Animals and Plants under Domestication" could
but further increase that acceptance. It is, however, somewhat
problematical how far such anticipations will be realized. The newer book
seems to add after all but little in support of the theory, and to leave
most, if not all, its difficulties exactly where they were. It is a
question, also, whether the hypothesis of "Pangenesis"[14] may not be found
rather to encumber than to support the theory it was intended to subserve.
However, the work in question treats only of domestic animals, and probably
the next instalment will address itself more vigorously and directly to the
difficulties which seem to us yet to bar the way to a complete acceptance
of the doctrine.

If the theory of Natural Selection can be shown to be quite insufficient to
explain any considerable number of important phenomena connected with the
origin of species, that theory, as _the_ explanation, must be considered as
provisionally discredited.

If other causes than Natural (including sexual) Selection can be proved to
have acted--if variation can in any cases be proved to be subject to
certain determinations in special directions by other means than Natural
Selection, it then becomes probable _a priori_ that it is so in others, and
that Natural Selection depends upon, and only supplements, such means, {20}
which conception is opposed to the pure Darwinian position.

Now it is certain, _a priori_, that variation is obedient to some law and
therefore that "Natural Selection" itself must be capable of being subsumed
into some higher law; and it is evident, I believe, _a posteriori_, that
Natural Selection is, at the very least, aided and supplemented by some
other agency.

Admitting, then, organic and other evolution, and that new forms of animals
and plants (new species, genera, &c.) have from time to time been evolved
from preceding animals and plants, it follows, if the views here advocated
are true, that this evolution has not taken place by the action of "Natural
Selection" _alone_, but through it (amongst other influences) aided by the
concurrent action of some other natural law or laws, at present
undiscovered; and probably that the genesis of species takes place partly,
perhaps mainly, through laws which may be most conveniently spoken of as
special powers and tendencies existing in each organism; and partly through
influences exerted on each by surrounding conditions and agencies organic
and inorganic, terrestrial and cosmical, among which the "survival of the
fittest" plays a certain but subordinate part.

The theory of "Natural Selection" may (though it need not) be taken in such
a way as to lead men to regard the present organic world as formed, so to
speak, _accidentally_, beautiful and wonderful as is confessedly the
hap-hazard result. The same may perhaps be said with regard to the system
advocated by Mr. Herbert Spencer, who, however, also relegates "Natural
Selection" to a subordinate _rôle_. The view here advocated, on the other
hand, regards the whole organic world as arising and going forward in one
harmonious development similar to that which displays itself in the growth
and action of each separate individual organism. It also regards each such
separate organism as the expression of powers and tendencies not to be {21}
accounted for by "Natural Selection" alone, or even by that together with
merely the direct influence of surrounding conditions.

The difficulties which appear to oppose themselves to the reception of
"Natural Selection" or "the survival of the fittest," as the one
explanation of the origin of species, have no doubt been already considered
by Mr. Darwin. Nevertheless, it may be worth while to enumerate them, and
to state the considerations which appear to give them weight; and there is
no doubt but that a naturalist so candid and careful as the author of the
theory in question, will feel obliged, rather than the reverse, by the
suggestion of all the doubts and difficulties which can be brought against
it.

What is to be brought forward may be summed up as follows:--

That "Natural Selection" is incompetent to account for the incipient stages
of useful structures.

That it does not harmonize with the co-existence of closely similar
structures of diverse origin.

That there are grounds for thinking that specific differences may be
developed suddenly instead of gradually.

That the opinion that species have definite though very different limits to
their variability is still tenable.

That certain fossil transitional forms are absent, which might have been
expected to be present.

That some facts of geographical distribution supplement other difficulties.

That the objection drawn from the physiological difference between
"species" and "races" still exists unrefuted.

That there are many remarkable phenomena in organic forms upon which
"Natural Selection" throws no light whatever, but the explanations of
which, if they could be attained, might throw light upon specific
origination. [Page 22]

Besides these objections to the sufficiency of "Natural Selection," others
may be brought against the hypothesis of "Pangenesis," which, professing as
it does to explain great difficulties, seems to do so by presenting others
not less great--almost to be the explanation of _obscurum per          {23}
obscurius_.

CHAPTER II.

THE INCOMPETENCY OF "NATURAL SELECTION" TO ACCOUNT FOR THE INCIPIENT STAGES
OF USEFUL STRUCTURES.

    Mr. Darwin supposes that natural selection acts by slight
    variations.--These must be useful at once.--Difficulties as to the
    giraffe; as to mimicry; as to the heads of flat-fishes; as to the
    origin and constancy of the vertebrate limbs; as to whalebone; as to
    the young kangaroo; as to sea-urchins; as to certain processes of
    metamorphosis; as to the mammary gland; as to certain ape characters;
    as to the rattlesnake and cobra; as to the process of formation of the
    eye and ear; as to the fully developed condition of the eye and ear; as
    to the voice; as to shell-fish; as to orchids; as to ants.--The
    necessity for the simultaneous modification of many
    individuals.--Summary and conclusion.

"Natural Selection," simply and by itself, is potent to explain the
maintenance or the further extension and development of favourable
variations, which are at once sufficiently considerable to be useful from
the first to the individual possessing them. But Natural Selection utterly
fails to account for the conservation and development of the minute and
rudimentary beginnings, the slight and infinitesimal commencements of
structures, however useful those structures may afterwards become.

Now, it is distinctly enunciated by Mr. Darwin, that the spontaneous
variations upon which his theory depends are individually slight, minute,
and insensible. He says,[15] "Slight individual differences, however,  {24}
suffice for the work, and are probably the sole differences which are
effective in the production of new species." And again, after mentioning
the frequent sudden appearances of domestic varieties, he speaks of "the
false belief as to the similarity of natural species in this respect."[16]
In his work on the "Origin of Species," he also observes, "Natural
Selection acts only by the preservation and accumulation of small inherited
modifications."[17] And "Natural Selection, if it be a true principle, will
banish the belief ... of any great and sudden modification in their
structure."[18] Finally, he adds, "If it could be demonstrated that any
complex organ existed, which could not possibly have been formed by
numerous, successive, slight modifications, my theory would absolutely
break down."[19]

Now the conservation of minute variations in many instances is, of course,
plain and intelligible enough; such, _e.g._, as those which tend to promote
the destructive faculties of beasts of prey on the one hand, or to
facilitate the flight or concealment of the animals pursued on the other;
provided always that these minute beginnings are of such a kind as really
to have a certain efficiency, however small, in favour of the conservation
of the individual possessing them; and also provided that no unfavourable
peculiarity in any other direction accompanies and neutralizes, in the
struggle for life, the minute favourable variation.

But some of the cases which have been brought forward, and which have met
with very general acceptance, seem less satisfactory when carefully
analysed than they at first appear to be. Amongst these we may mention "the
neck of the giraffe."

At first sight it would seem as though a better example in support of
"Natural Selection" could hardly have been chosen. Let the fact of the {25}
occurrence of occasional, severe droughts in the country which that animal
has inhabited be granted. In that case, when the ground vegetation has been
consumed, and the trees alone remain, it is plain that at such times only
those individuals (of what we assume to be the nascent giraffe species)
which were able to reach high up would be preserved, and would become the
parents of the following generation, some individuals of which would, of
course, inherit that high-reaching power which alone preserved their
parents. Only the high-reaching issue of these high-reaching individuals
would again, _cæteris paribus_, be preserved at the next drought, and would
again transmit to their offspring their still loftier stature; and so on,
from period to period, through æons of time, all the individuals tending to
revert to the ancient shorter type of body, being ruthlessly destroyed at
the occurrence of each drought.

(1.) But against this it may be said, in the first place, that the argument
proves too much; for, on this supposition, many species must have tended to
undergo a similar modification, and we ought to have at least several
forms, similar to the giraffe, developed from different Ungulata.[20] A
careful observer of animal life, who has long resided in South Africa,
explored the interior, and lived in the giraffe country, has assured the
Author that the giraffe has powers of locomotion and endurance fully equal
to those possessed by any of the other Ungulata of that continent. It would
seem, therefore, that some of these other Ungulates ought to have developed
in a similar manner as to the neck, under pain of being starved, when the
long neck of the giraffe was in its incipient stage.

To this criticism it has been objected that different kinds of animals are
preserved, in the struggle for life, in very different ways, and even  {26}
that "high reaching" may be attained in more modes than one--as, for
example, by the trunk of the elephant. This is, indeed, true, but then none
of the African Ungulata[21] have, nor do they appear ever to have had, any
proboscis whatsoever; nor have they acquired such a development as to allow
them to rise on their hind limbs and graze on trees in a kangaroo-attitude,
nor a power of climbing, nor, as far as known, any other modification
tending to compensate for the comparative shortness of the neck. Again, it
may perhaps be said that leaf-eating forms are exceptional, and that
therefore the struggle to attain high branches would not affect many
Ungulates. But surely, when these severe droughts necessary for the theory
occur, the ground vegetation is supposed to be exhausted; and, indeed, the
giraffe is quite capable of feeding from off the ground. So that, in these
cases, the other Ungulata _must_ have taken to leaf eating or have starved,
and thus must have had any accidental long-necked varieties favoured and
preserved exactly as the long-necked varieties of the giraffe are supposed
to have been favoured and preserved.

The argument as to the different modes of preservation has been very well
put by Mr. Wallace,[22] in reply to the objection that "colour, being
dangerous, should not exist in nature." This objection appears similar to
mine; as I say that a giraffe neck, being needful, there should be many
animals with it, while the objector noticed by Mr. Wallace says, "a dull
colour being needful, all animals should be so coloured." And Mr. Wallace
shows in reply how porcupines, tortoises and mussels, very hard-coated
bombadier beetles, stinging insects and nauseous-tasted caterpillars, can
afford to be brilliant by the various means of active defence or passive
protection they possess, other than obscure colouration. He says "the  {27}
attitudes of some insects may also protect them, as the habit of turning up
the tail by the harmless rove-beetles (Staphylinidæ) no doubt leads other
animals, besides children, to the belief that they can sting. The curious
attitude assumed by sphinx caterpillars is probably a safeguard, as well as
the blood-red tentacles which can suddenly be thrown out from the neck by
the caterpillars of all the true swallow-tailed butterflies."

But, because many different kinds of animals can elude the observation or
defy the attack of enemies in a great variety of ways, it by no means
follows that there are any similar number and variety of ways for attaining
vegetable food in a country where all such food, other than the lofty
branches of trees, has been for a time destroyed. In such a country we have
a number of vegetable-feeding Ungulates, all of which present minute
variations as to the length of the neck. If, as Mr. Darwin contends, the
natural selection of these favourable variations has alone lengthened the
neck of the giraffe by preserving it during droughts; similar variations,
in similarly-feeding forms, at the same times, ought similarly to have been
preserved and so lengthened the neck of some other Ungulates by similarly
preserving them during the same droughts.

(2.) It may be also objected, that the power of reaching upwards, acquired
by the lengthening of the neck and legs, must have necessitated a
considerable increase in the entire size and mass of the body (larger bones
requiring stronger and more voluminous muscles and tendons, and these again
necessitating larger nerves, more capacious blood-vessels, &c.), and it is
very problematical whether the disadvantages thence arising would not, in
times of scarcity, more than counterbalance the advantages.

For a considerable increase in the supply of food would be requisite on
account of this increase in size and mass, while at the same time there
would be a certain decrease in strength; for, as Mr. Herbert Spencer   {28}
says,[23] "It is demonstrable that the excess of absorbed over expended
nutriment must, other things equal, become less as the size of an animal
becomes greater. In similarly-shaped bodies, the masses vary as the cubes
of the dimensions; whereas the strengths vary as the squares of the
dimensions.".... "Supposing a creature which a year ago was one foot high,
has now become two feet high, while it is unchanged in proportions and
structure--what are the necessary concomitant changes that have taken place
in it? It is eight times as heavy; that is to say, it has to resist eight
times the strain which gravitation puts on its structure; and in producing,
as well as in arresting, every one of its movements, it has to overcome
eight times the inertia. Meanwhile, the muscles and bones have severally
increased their contractile and resisting powers, in proportion to the
areas of their transverse sections; and hence are severally but four times
as strong as they were. Thus, while the creature has doubled in height, and
while its ability to overcome forces has quadrupled, the forces it has to
overcome have grown eight times as great. Hence, to raise its body through
a given space, its muscles have to be contracted with twice the intensity,
at a double cost of matter expended." Again, as to the cost at which
nutriment is distributed through the body, and effete matters removed from
it, "Each increment of growth being added at the periphery of an organism,
the force expended in the transfer of matter must increase in a rapid
progression--a progression more rapid than that of the mass."

There is yet another point. Vast as may have been the time during which the
process of evolution has continued, it is nevertheless not infinite. Yet,
as every kind, on the Darwinian hypothesis, varies slightly but
indefinitely in every organ and every part of every organ, how very
generally must favourable variations as to the length of the neck have {29}
been accompanied by some unfavourable variation in some other part,
neutralizing the action of the favourable one, the latter, moreover, only
taking effect during these periods of drought! How often must not
individuals, favoured by a slightly increased length of neck, have failed
to enjoy the elevated foliage which they had not strength or endurance to
attain; while other individuals, exceptionally robust, could struggle on
yet further till they arrived at vegetation within their reach.

However, allowing this example to pass, many other instances will be found
to present great difficulties.

Let us take the cases of mimicry amongst lepidoptera and other insects. Of
this subject Mr. Wallace has given a most interesting and complete
account,[24] showing in how many and strange instances this superficial
resemblance by one creature to some other quite distinct creature acts as a
safeguard to the first. One or two instances must here suffice. In South
America there is a family of butterflies, termed _Heliconidæ_, which are
very conspicuously coloured and slow in flight, and yet the individuals
abound in prodigious numbers, and take no precautions to conceal
themselves, even when at rest, during the night. Mr. Bates (the author of
the very interesting work "The Naturalist on the River Amazons," and the
discoverer of "Mimicry") found that these conspicuous butterflies had a
very strong and disagreeable odour; so much so that any one handling them
and squeezing them, as a collector must do, has his fingers stained and so
infected by the smell, as to require time and much trouble to remove it.

It is suggested that this unpleasant quality is the cause of the abundance
of the Heliconidæ; Mr. Bates and other observers reporting that they have
never seen them attacked by the birds, reptiles, or insects which prey upon
other lepidoptera.

Now it is a curious fact that very different South American butterflies{30}
put on, as it were, the exact dress of these offensive beauties and mimic
them even in their mode of flight.

In explaining the mode of action of this protecting resemblance Mr. Wallace
observes:[25] "Tropical insectivorous birds very frequently sit on dead
branches of a lofty tree, or on those which overhang forest paths, gazing
intently around, and darting off at intervals to seize an insect at a
considerable distance, with which they generally return to their station to
devour. If a bird began by capturing the slow-flying conspicuous
Heliconidæ, and found them always so disagreeable that it could not eat
them, it would after a very few trials leave off catching them at all; and
their whole appearance, form, colouring, and mode of flight is so peculiar,
that there can be little doubt birds would soon learn to distinguish them
at a long distance, and never waste any time in pursuit of them. Under
these circumstances, it is evident that any other butterfly of a group
which birds were accustomed to devour, would be almost equally well
protected by closely resembling a Heliconia externally, as if it acquired
also the disagreeable odour; always supposing that there were only a few of
them among a great number of Heliconias."

"The approach in colour and form to the Heliconidæ, however, would be at
the first a positive, though perhaps a slight, advantage; for although at
short distances this variety would be easily distinguished and devoured,
yet at a longer distance it might be mistaken for one of the uneatable
group, and so be passed by and gain another day's life, which might in many
cases be sufficient for it to lay a quantity of eggs and leave a numerous
progeny, many of which would inherit the peculiarity which had been the
safeguard of their parent."

[Illustration: LEAF BUTTERFLY IN FLIGHT AND REPOSE.
(_From Mr. Wallace's_ "_Malay Archipelago._")]

As a complete example of mimicry Mr. Wallace refers to a common Indian
butterfly. He says:[26] "But the most wonderful and undoubted case of
protective resemblance in a butterfly, which I have ever seen, is that {31}
of the common Indian _Kallima inachis_, and its Malayan ally, _Kallima
paralekta_. The upper surface of these is very striking and showy, as they
are of a large size, and are adorned with a broad band of rich orange  {32}
on a deep bluish ground. The under side is very variable in colour, so that
out of fifty specimens no two can be found exactly alike, but every one of
them will be of some shade of ash, or brown, or ochre, such as are found
among dead, dry, or decaying leaves. The apex of the upper wings is
produced into an acute point, a very common form in the leaves of tropical
shrubs and trees, and the lower wings are also produced into a short narrow
tail. Between these two points runs a dark curved line exactly representing
the midrib of a leaf, and from this radiate on each side a few oblique
lines, which serve to indicate the lateral veins of a leaf. These marks are
more clearly seen on the outer portion of the base of the wings, and on the
inner side towards the middle and apex, and it is very curious to observe
how the usual marginal and transverse striæ of the group are here modified
and strengthened so as to become adapted for an imitation of the venation
of a leaf." ... "But this resemblance, close as it is, would be of little
use if the habits of the insect did not accord with it. If the butterfly
sat upon leaves or upon flowers, or opened its wings so as to expose the
upper surface, or exposed and moved its head and antennæ as many other
butterflies do, its disguise would be of little avail. We might be sure,
however, from the analogy of many other cases, that the habits of the
insect are such as still further to aid its deceptive garb; but we are not
obliged to make any such supposition, since I myself had the good fortune
to observe scores of _Kallima paralekta_, in Sumatra, and to capture many
of them, and can vouch for the accuracy of the following details. These
butterflies frequent dry forests, and fly very swiftly. They were seen to
settle on a flower or a green leaf, but were many times lost sight of in a
bush or tree of dead leaves. On such occasions they were generally searched
for in vain, for while gazing intently at the very spot where one had
disappeared, it would often suddenly dart out, and again vanish twenty or
fifty yards further on. On one or two occasions the insect was detected{33}
reposing, and it could then be seen how completely it assimilates itself to
the surrounding leaves. It sits on a nearly upright twig, the wings fitting
closely back to back, concealing the antennæ and head, which are drawn up
between their bases. The little tails of the hind wing touch the branch,
and form a perfect stalk to the leaf, which is supported in its place by
the claws of the middle pair of feet, which are slender and inconspicuous.
The irregular outline of the wings gives exactly the perspective effect of
a shrivelled leaf. We thus have size, colour, form, markings, and habits,
all combining together to produce a disguise which may be said to be
absolutely perfect; and the protection which it affords is sufficiently
indicated by the abundance of the individuals that possess it."

Beetles also imitate bees and wasps, as do some Lepidoptera; and objects
the most bizarre and unexpected are simulated, such as dung and drops of
dew. Some insects, called bamboo and walking-stick insects, have a most
remarkable resemblance to pieces of bamboo, to twigs and branches. Of these
latter insects Mr. Wallace says:[27] "Some of these are a foot long and as
thick as one's finger, and their whole colouring, form, rugosity, and the
arrangement of the head, legs, and antennæ, are such as to render them
absolutely identical in appearance with dry sticks. They hang loosely about
shrubs in the forest, and have the extraordinary habit of stretching out
their legs unsymmetrically, so as to render the deception more complete."
Now let us suppose that the ancestors of these various animals were all
destitute of the very special protections they at present possess, as on
the Darwinian hypothesis we must do. Let it also be conceded that small
deviations from the antecedent colouring or form would tend to make some of
their ancestors escape destruction by causing them more or less frequently
to be passed over, or mistaken by their persecutors. Yet the deviation {34}
must, as the event has shown, in each case be in some definite direction,
whether it be towards some other animal or plant, or towards some dead or
inorganic matter. But as, according to Mr. Darwin's theory, there is a
constant tendency to indefinite variation, and as the minute incipient
variations will be in _all directions_, they must tend to neutralize each
other, and at first to form such unstable modifications that it is
difficult, if not impossible, to see how such indefinite oscillations of
infinitesimal beginnings can ever build up a sufficiently appreciable
resemblance to a leaf, bamboo, or other object, for "Natural Selection" to
seize upon and perpetuate. This difficulty is augmented when we consider--a
point to be dwelt upon hereafter--how necessary it is that many individuals
should be similarly modified simultaneously. This has been insisted on in
an able article in the _North British Review_ for June 1867, p. 286, and
the consideration of the article has occasioned Mr. Darwin to make an
important modification in his views.[28]

In these cases of mimicry it seems difficult indeed to imagine a reason why
variations tending in an _infinitesimal degree_ in any special direction
should be preserved. All variations would be preserved which tended to
obscure the perception of an animal by its enemies, whatever direction
those variations might take, and the common preservation of conflicting
tendencies would greatly favour their mutual neutralization and
obliteration if we may rely on the many cases recently brought forward by
Mr. Darwin with regard to domestic animals.

[Illustration: THE WALKING-LEAF INSECT.]

Mr. Darwin explains the imitation of some species by others more or less
nearly allied to it, by the common origin of both the mimic and the
mimicked species, and the consequent possession by both (according to the
theory of "Pangenesis") of gemmules tending to reproduce ancestral
characters, which characters the mimic must be assumed first to have   {35}
lost and then to have recovered. Mr. Darwin says,[29] "Varieties of one
species frequently mimic distinct species, a fact in perfect harmony with
the foregoing cases, and explicable _only on the theory of descent_." But
this at the best is but a partial and very incomplete explanation. It is
one, moreover, which Mr. Wallace does not accept.[30] It is very
incomplete, because it has no bearing on some of the most striking cases,
and of course Mr. Darwin does not pretend that it has. We should have to go
back far indeed to reach the common ancestor of the mimicking          {36}
walking-leaf insect and the real leaf it mimics, or the original progenitor
of both the bamboo insect and the bamboo itself. As these last most
remarkable cases have certainly nothing to do with heredity,[31] it is
unwarrantable to make use of that explanation for other protective
resemblances, seeing that its inapplicability, in certain instances, is so
manifest.

Again, at the other end of the process it is as difficult to account for
the last touches of perfection in the mimicry. Some insects which imitate
leaves extend the imitation even to the very injuries on those leaves made
by the attacks of insects or of fungi. Thus, speaking of one of the
walking-stick insects, Mr. Wallace says:[32] "One of these creatures
obtained by myself in Borneo (_Ceroxylus laceratus_) was covered over with
foliaceous excrescences of a clear olive-green colour, so as exactly to
resemble a stick grown over by a creeping moss or jungermannia. The Dyak
who brought it me assured me it was grown over with moss although alive,
and it was only after a most minute examination that I could convince
myself it was not so." Again, as to the leaf butterfly, he says:[33] "We
come to a still more extraordinary part of the imitation, for we find
representations of leaves in every stage of decay, variously blotched, and
mildewed, and pierced with holes, and in many cases irregularly covered
with powdery black dots, gathered into patches and spots, so closely
resembling the various kinds of minute fungi that grow on dead leaves, that
it is impossible to avoid thinking at first sight that the butterflies
themselves have been attacked by real fungi."

Here imitation has attained a development which seems utterly beyond the
power of the mere "survival of the fittest" to produce. How this double
mimicry can importantly aid in the struggle for life seems puzzling indeed,
but much more so how the first faint beginnings of the imitation of    {37}
such injuries in the leaf can be developed in the animal into such a
complete representation of them--_a fortiori_ how simultaneous and similar
first beginnings of imitations of such injuries could ever have been
developed in several individuals, out of utterly indifferent and
indeterminate infinitesimal variations in all conceivable directions.

[Illustration: PLEURONECTIDÆ, WITH THE PECULIARLY PLACED EYE IN DIFFERENT
POSITIONS.
(_From Dr. Traquair's paper in the "Transactions of the Linnean Society,
1865."_)]

Another instance which may be cited is the asymmetrical condition of the
heads of the flat-fishes (Pleuronectidæ), such as the sole, the flounder,
the brill, the turbot, &c. In all these fishes the two eyes, which in the
young are situated as usual one on each side, come to be placed, in the
adult, both on the same side of the head. If this condition had appeared at
once, if in the hypothetically fortunate common ancestor of these fishes an
eye had suddenly become thus transferred, then the perpetuation of such a
transformation by the action of "Natural Selection" is conceivable enough.
Such sudden changes, however, are not those favoured by the Darwinian
theory, and indeed the accidental occurrence of such a spontaneous
transformation is hardly conceivable. But if this is not so, if the transit
was gradual, then how such transit of one eye a minute fraction of the {38}
journey towards the other side of the head could benefit the individual is
indeed far from clear. It seems, even, that such an incipient
transformation must rather have been injurious. Another point with regard
to these flat-fishes is that they appear to be in all probability of recent
origin--_i.e._ geologically speaking. There is, of course, no great stress
to be laid on the mere absence of their remains from the secondary strata,
nevertheless that absence is noteworthy, seeing that existing fish
families, _e.g._ sharks (Squalidæ), have been found abundantly even down so
far as the carboniferous rocks, and traces of them in the Upper Silurian.

Another difficulty seems to be the first formation of the limbs of the
higher animals. The lowest Vertebrata[34] are perfectly limbless, and if,
as most Darwinians would probably assume, the primeval vertebrate creature
was also apodal, how are the preservation and development of the first
rudiments of limbs to be accounted for--such rudiments being, on the
hypothesis in question, infinitesimal and functionless?

In reply to this it has been suggested that a mere flattening of the end of
the body has been useful, such, _e.g._, as we see in sea-snakes,[35] which
may be the rudiment of a tail formed strictly to aid in swimming. Also that
a mere _roughness_ of the skin might be useful to a swimming animal by
holding the water better, that thus minute processes might be selected and
preserved, and that, in the same way, these might be gradually increased
into limbs. But it is, to say the least, very questionable whether a
roughness of the skin, or minute processes, would be useful to a       {39}
swimming animal; the motion of which they would as much impede as aid,
unless they were at once capable of a suitable and appropriate action,
which is against the hypothesis. Again, the change from mere indefinite and
accidental processes to two regular pairs of symmetrical limbs, as the
result of merely fortuitous, favouring variations, is a step the
feasibility of which hardly commends itself to the reason, seeing the very
different positions assumed by the ventral fins in different fishes. If the
above suggestion made in opposition to the views here asserted be true,
then the general constancy of position of the limbs of vertebrata may be
considered as due to the position assumed by the primitive rugosities from
which those limbs were generated. Clearly only two pairs of rugosities were
so preserved and developed, and all limbs (on this view) are descendants of
the same two pairs, as all have so similar a fundamental structure. Yet we
find in many fishes the pair of fins, which correspond to the hinder limbs
of other animals, placed so far forwards as to be either on the same level
with, or actually in front of, the normally anterior pair of limbs; and
such fishes are from this circumstance called "thoracic," or "jugular"
fishes respectively, as the weaver fishes and the cod. This is a wonderful
contrast to the fixity of position of vertebrate limbs generally. If then
such a change can have taken place in the comparatively short time occupied
by the evolution of these special fish forms, we might certainly expect
other and far more bizarre structures would (did not some law forbid) have
been developed, from other rugosities, in the manifold exigencies of the
multitudinous organisms which must (on the Darwinian hypothesis) have been
gradually evolved during the enormous period intervening between the first
appearance of vertebrate life and the present day. Yet, with these
exceptions, the position of the limbs is constant from the lower fishes up
to man, there being always an anterior pectoral pair placed in front of a
posterior or pelvic pair when both are present, and in no single       {40}
instance are there more than these two pairs.

[Illustration: MOUTH OF A WHALE.]

The development of whalebone (baleen) in the mouth of the whale is another
difficulty. A whale's mouth is furnished with very numerous horny plates,
which hang down from the palate along each side of the mouth. They thus
form two longitudinal series, each plate of which is placed transversely to
the long axis of the body, and all are very close together. On depressing
the lower lip the free outer edges of these plates come into view. Their
inner edges are furnished with numerous coarse hair-like processes,
consisting of some of the constituent fibres of the horny plates--which, as
it were, fray out--and the mouth is thus lined, except below, by a network
of countless fibres formed by the inner edges of the two series of plates.
This network acts as a sort of sieve. When the whale feeds it takes    {41}
into its mouth a great gulp of water, which it drives out again through the
intervals of the horny plates of baleen, the fluid thus traversing the
sieve of horny fibres, which retains the minute creatures on which these
marine monsters subsist. Now it is obvious, that if this baleen had once
attained such a size and development as to be at all useful, then its
preservation and augmentation within serviceable limits, would be promoted
by "Natural Selection" alone. But how to obtain the beginning of such
useful development? There are indeed certain animals of exclusively aquatic
habits (the dugong and manatee) which also possess more or less horn on the
palate, and at first sight this might be taken as a mitigation of the
difficulty; but it is not so, and the fact does not help us one step
further along the road: for, in the first place, these latter animals
differ so importantly in structure from whales and porpoises that they form
an altogether distinct order, and cannot be thought to approximate to the
whale's progenitors. They are vegetarians, the whales feed on animals; the
former never have the ribs articulated in the mode in which they are in
some of the latter; the former have pectoral mammæ, and the latter are {42}
provided with two inguinal mammary glands, and have the nostrils enlarged
into blowers, which the former have not. The former thus constitute the
order Sirenia, while the latter belong to the Cetacea. In the second place,
the horny matter on the palates of the dugong and manatee has not, even
initially, that "strainer" action, which is the characteristic function of
the Cetacean "baleen."

[Illustration: FOUR PLATES OF BALEEN SEEN OBLIQUELY FROM WITHIN.]

[Illustration: DUGONG.]

There is another very curious structure, the origin or the disappearance of
which it seems impossible to account for on the hypothesis of minute
indefinite variations. It is that of the mouth of the young kangaroo. In
all mammals, as in ourselves, the air-passage from the lungs opens in the
floor of the mouth behind the tongue, and in front of the opening of the
gullet, so that each particle of food as it is swallowed passes over the
opening, but is prevented from falling into it (and thus causing death from
choking) by the action of a small cartilaginous shield (the epiglottis),
which at the right moment bends back and protects the orifice. Now the
kangaroo is born in such an exceedingly imperfect and undeveloped
condition, that it is quite unable to suck. The mother therefore places the
minute blind and naked young upon the nipple, and then injects milk into it
by means of a special muscular envelope of the mammary gland. Did no
special provision exist, the young one must infallibly be choked by the
intrusion of the milk into the windpipe. But there _is_ a special
provision. The larynx is so elongated that it rises up into the posterior
end of the nasal passage, and is thus enabled to give free entrance to the
air for the lungs, while the milk passes harmlessly on each side of this
elongated larynx, and so safely attains the gullet behind it.

Now, on the Darwinian hypothesis, either all mammals descended from
marsupial progenitors, or else the marsupials, sprung from animals having
in most respects the ordinary mammalian structure. [Page 43]

On the first alternative, how did "Natural Selection" remove this (at least
perfectly innocent and harmless) structure in almost all other mammals,
and, having done so, again reproduce it in precisely those forms which
alone require it, namely, the Cetacea? That such a harmless structure _need
not_ be removed any Darwinian must confess, since a structure exists in
both the crocodiles and gavials, which enables the former to breathe
themselves while drowning the prey which they hold in their mouths. On Mr.
Darwin's hypothesis it could only have been developed where useful,
therefore not in the gavials(!) which feed on fish, but which yet retain,
as we might expect, this, in them superfluous but harmless formation.

On the second alternative, how did the elongated larynx itself arise,
seeing that if its development lagged behind that of the maternal
structure, the young primeval kangaroo must be choked: while without the
injecting power in the mother, it must be starved? The struggle by the sole
action of which such a form was developed must indeed have been severe!

[Illustration: AN ECHINUS, OR SEA-URCHIN
(The spines removed from one-half.)]

The sea-urchins (Echinus) present us also with structures the origin of
which it seems impossible to explain by the action of "Natural         {44}
Selection" only. These lowly animals belong to that group of the star-fish
class (Echinodermata), the species of which possess generally spheroidal
bodies, built up of multitudinous calcareous plates, and constitute the
order Echinoidea. They are also popularly known as sea-eggs. Utterly devoid
of limbs, the locomotion of these creatures is effected by means of rows of
small tubular suckers (which protrude through pores in the calcareous
plates) and by moveable spines scattered over the body.

[Illustration: PEDICELLARIÆ. (Immensely enlarged.)]

Besides these spines and suckers there are certain very peculiar
structures, termed "Pedicellariæ." Each of these consists of a long slender
stalk, ending in three short limbs--or rather jaws--the whole supported by
a delicate internal skeleton. The three limbs (or jaws), which start from a
common point at the end of the stalk, are in the constant habit of opening
and closing together again with a snapping action, while the stalk itself
sways about. The utility of these appendages is, even now, problematical.
It may be that they remove from the surface of the animal's body foreign
substances which would be prejudicial to it, and which it cannot otherwise
get rid of. But granting this, what would be the utility of the _first
rudimentary beginnings_ of such structures, and how could such incipient
buddings have ever preserved the life of a single Echinus? It is true that
on Darwinian principles the ancestral form from which the sea-urchin
developed was different, and must not be conceived merely as an Echinus
devoid of pedicellariæ; but this makes the difficulty none the less. It is
equally hard to imagine that the first rudiments of such structures could
have been useful to _any_ animal from which the Echinus might have been{45}
derived. Moreover, not even the _sudden_ development of the snapping action
could have been beneficial without the freely moveable stalk, nor could the
latter have been efficient without the snapping jaws, yet no minute merely
indefinite variations could simultaneously evolve these complex
co-ordinations of structure; to deny this seems to do no less than to
affirm a startling paradox.

Mr. Darwin explains the appearance of some structures, the utility of which
is not apparent, by the existence of certain "laws of correlation." By
these he means that certain parts or organs of the body are so related to
other organs or parts, that when the first are modified by the action of
"Natural Selection," or what not, the second are simultaneously affected,
and increase proportionally or possibly so decrease. Examples of such are
the hair and teeth in the naked Turkish dog, the general deafness of white
cats with blue eyes, the relation between the presence of more or less down
on young birds when first hatched, and the future colour of their
plumage,[36] with many others. But the idea that the modification of any
internal or external part of the body of an Echinus carries with it the
effect of producing elongated, flexible, triradiate, snapping processes,
is, to say the very least, fully as obscure and mysterious as what is here
contended for, viz. the efficient presence of an unknown internal natural
law or laws conditioning the evolution of new specific forms from preceding
ones, modified by the action of surrounding conditions, by "Natural
Selection" and by other controlling influences.

The same difficulty seems to present itself in other examples of
exceptional structure and action. In the same Echinus, as in many allied
forms, and also in some more or less remote ones, a very peculiar mode of
development exists. The adult is not formed from the egg directly, but {46}
the egg gives rise to a creature which swims freely about, feeds, and is
even somewhat complexly organized. Soon a small lump appears on one side of
its stomach; this enlarges, and, having established a communication with
the exterior, envelopes and appropriates the creature's stomach, with which
it swims away and develops into the complete adult form, while the
dispossessed individual perishes.

Again, certain flies present a mode of development equally bizarre, though
quite different. In these flies, the grub is, as usual, produced from the
ovum, but this grub, instead of growing up into the adult in the ordinary
way, undergoes a sort of liquefaction of a great part of its body, while
certain patches of formative tissue, which are attached to the ramifying
air tubes, or tracheæ (and which patches bear the name of "imaginal
disks"), give rise to the legs, wings, eyes, &c., respectively; and these
severally formed parts grow together, and build up the head and body by
their mutual approximation. Such a process is unknown outside the class of
insects, and inside that class it is only known in a few of the two-winged
flies. Now, how "Natural Selection," or any "laws of correlation," can
account for the gradual development of such an exceptional process of
development--so extremely divergent from that of other insects--seems
nothing less than inconceivable. Mr. Darwin himself[37] gives an account of
a very peculiar and abnormal mode of development of a certain beetle, the
sitaris, as described by M. Fabre. This insect, instead of at first
appearing in its grub stage, and then, after a time, putting on the adult
form, is at first active and furnished with six legs, two long antennæ, and
four eyes. Hatched in the nests of bees, it at first attaches itself to one
of the males, and then crawls, when the opportunity offers, upon a female
bee. When the female bee lays her eggs, the young sitaris springs upon them
and devours them. Then, losing its eyes, legs, and antennæ, and        {47}
becoming rudimentary, it sinks into an ordinary grub-like form, and feeds
on honey, ultimately undergoing another transformation, re-acquiring its
legs, &c., and emerging a perfect beetle! That such a process should have
arisen by the accumulation of minute accidental variations in structure and
habit, appears to many minds, quite competent to form an opinion on the
subject, absolutely incredible.

It may be objected, perhaps, that these difficulties are _difficulties of
ignorance_--that we cannot explain them because we do not know _enough_ of
the animals. But it is here contended that this is not the case; it is not
that we merely fail to see how Natural Selection acted, but that there is a
positive incompatibility between the cause assigned and the results. It
will be stated shortly what wonderful instances of co-ordination and of
unexpected utility Mr. Darwin has discovered in orchids. The discoveries
are not disputed or undervalued, but the explanation of their _origin_ is
deemed thoroughly unsatisfactory--utterly insufficient to explain the
incipient, infinitesimal beginnings of structures which are of utility only
when they are considerably developed.

Let us consider the mammary gland, or breast. Is it conceivable that the
young of any animal was ever saved from destruction by accidentally sucking
a drop of scarcely nutritious fluid from an accidentally hypertrophied
cutaneous gland of its mother? And even if one was so, what chance was
there of the perpetuation of such a variation? On the hypothesis of Natural
Selection itself, we must assume that up to that time the race had been
well adapted to the surrounding conditions; the temporary and accidental
trial and change of conditions, which caused the so-sucking young one to be
the "fittest to survive" under the supposed circumstances, would soon cease
to act, and then the progeny of the mother, with the accidentally
hypertrophied, sebaceous glands, would have no tendency to survive the {48}
far outnumbering descendants of the normal ancestral form. If, on the other
hand, we assume the change of conditions not to have been temporary but
permanent, and also assume that this permanent change of conditions was
accidentally synchronous with the change of structure, we have a
coincidence of very remote probability indeed. But if, again, we accept the
presence of some harmonizing law simultaneously determining the two
changes, or connecting the second with the first by causation, then, of
course, we remove the accidental character of the coincidence.

Again, how explain the external position of the male sexual glands in
certain mammals? The utility of the modification, when accomplished, is
problematical enough, and no less so the incipient stages of the descent.

As was said in the first chapter, Mr. Darwin explains the brilliant plumage
of the peacock or the humming-bird by the action of sexual selection: the
more and more brilliant males being selected by the females (which are thus
attracted) to become the fathers of the next generation, to which
generation they tend to communicate their own bright nuptial vesture. But
there are peculiarities of colour and of form which it is exceedingly
difficult to account for by any such action. Thus, amongst apes, the female
is notoriously weaker, and is armed with much less powerful canine tusks
than the male. When we consider what is known of the emotional nature of
these animals, and the periodicity of its intensification, it is hardly
credible that a female would often risk life or limb through her admiration
of a trifling shade of colour, or an infinitesimally greater though
irresistibly fascinating degree of wartiness.[38]

                                                                       {49}
[Illustration: RATTLESNAKE.]

Yet the males of some kinds of ape are adorned with quite exceptionally
brilliant local decoration, and the male orang is provided with remarkable,
projecting, warty lumps of skin upon the cheeks. As we have said, the
weaker female can hardly be supposed to have developed these by persevering
and long-continued selection, nor can they be thought to tend to the
preservation of the individual. On the contrary, the presence of this
enlarged appendage must occasion a slight increase in the need of
nutriment, and in so far must be a detriment, although its detrimental
effect would not be worth speaking of except in relation to "Darwinism,"
according to which, "selection" has acted through unimaginable ages,   {50}
and has ever tended to suppress any useless development by the struggle for
life.[39]

[Illustration: COBRA.
(_Copied, by permission, from Sir Andrew Smith's "Reptiles of South
Africa."_)]

In poisonous serpents, also, we have structures which, at all events at
first sight, seem positively hurtful to those reptiles. Such are the rattle
of the rattlesnake, and the expanding neck of the cobra, the former seeming
to warn the ear of the intended victim, as the latter warns the eye. It is
true we cannot perhaps demonstrate that the victims are alarmed and warned,
but, on Darwinian principles, they certainly ought to be so. For the   {51}
rashest and most incautious of the animals preyed on would always tend to
fall victims, and the existing individuals being the long-descended progeny
of the timid and cautious, ought to have an inherited tendency to distrust,
amongst other things, both "rattling" and "expanding" snakes. As to any
power of fascination exercised by means of these actions, the most
distinguished naturalists, certainly the most distinguished erpetologists,
entirely deny it, and it is opposed to the careful observations of those
known to us.[40]

The mode of formation of both the eye and the ear of the highest animals is
such that, if it is (as most Darwinians assert processes of development to
be) a record of the actual steps by which such structures were first
evolved in antecedent forms, it almost amounts to a demonstration that
those steps were never produced by "Natural Selection."

The eye is formed by a simultaneous and corresponding ingrowth of one part
and outgrowth of another. The skin in front of the future eye becomes
depressed, the depression increases and assumes the form of a sac, which
changes into the aqueous humour and lens. An outgrowth of brain substance,
on the other hand, forms the retina, while a third process is a lateral
ingrowth of connective tissue, which afterwards changes into the vitreous
humour of the eye.

The internal ear is formed by an involution of the integument, and not by
an outgrowth of the brain. But tissue, in connexion with it, becomes in
part changed, thus forming the auditory nerve, which places the tegumentary
sac in direct communication with the brain itself.

                                                                       {52}
Now, these complex and simultaneous co-ordinations could never have been
produced by infinitesimal beginnings, since, until so far developed as to
effect the requisite junctions, they are useless. But the eye and ear when
fully developed present conditions which are hopelessly difficult to
reconcile with the mere action of "Natural Selection." The difficulties
with regard to the eye have been well put by Mr. Murphy, especially that of
the concordant result of visual development springing from different
starting-points and continued on by independent roads.

He says,[41] speaking of the beautiful structure of the perfect eye, "The
higher the organization, whether of an entire organism or of a single
organ, the greater is the number of the parts that co-operate, and the more
perfect is their co-operation; and consequently, the more necessity there
is for corresponding variations to take place in all the co-operating parts
at once, and the more useless will be any variation whatever unless it is
accompanied by corresponding variations in the co-operating parts; while it
is obvious that the greater the number of variations which are needed in
order to effect an improvement, the less will be the probability of their
all occurring at once. It is no reply to this to say, what is no doubt
abstractedly true, that whatever is possible becomes probable, if only time
enough be allowed. There are improbabilities so great that the common sense
of mankind treats them as impossibilities. It is not, for instance, in the
strictest sense of the word, impossible that a poem and a mathematical
proposition should be obtained by the process of shaking letters out of a
box; but it is improbable to a degree that cannot be distinguished from
impossibility; and the improbability of obtaining an improvement in an
organ by means of several spontaneous variations, all occurring together,
is an improbability of the same kind. If we suppose that any single
variation occurs on the average once in _m_ times, the probability of  {53}
that variation occurring in any individual will be

  1/_m_;

and suppose that _x_ variations must concur in order to make an
improvement, then the probability of the necessary variations all occurring
together will be

  1/_m_^x.

Now suppose, what I think a moderate proposition, that the value of _m_ is
1,000, and the value of _x_ is 10, then

  1/_m_^x = 1/1000^{10} = 1/10^{30}.

A number about ten thousand times as great as the number of waves of light
that have fallen on the earth since historical time began. And it is to be
further observed, that no improvement will give its possessor a _certainty_
of surviving and leaving offspring, but only an _extra chance_, the value
of which it is quite impossible to estimate." This difficulty is, as Mr.
Murphy points out, greatly intensified by the undoubted fact that the
wonderfully complex structure has been arrived at quite independently in
beasts on the one hand and in cuttle-fishes on the other; while creatures
of the insect and crab division present us with a third and quite
separately developed complexity.

As to the ear, it would take up too much space to describe its internal
structure;[42] it must suffice to say that in its interior there is an
immense series of minute rod-like bodies, termed _fibres of Corti_, having
the appearance of a key-board, and each fibre being connected with a
filament of the auditory nerve, these nerves being like strings to be
struck by the keys, _i.e._ by the fibres of Corti. Moreover, this apparatus
is supposed to be a key-board in function as well as in appearance, the{54}
vibration of each one fibre giving rise, it is believed, to the sensation
of one particular tone, and combinations of such vibrations producing
chords. It is by the action of this complex organ then, that all the
wonderful intricacy and beauty of Beethoven and Mozart come, most probably,
to be perceived and appreciated.

Now it can hardly be contended that the preservation of any race of men in
the struggle for life ever depended on such an extreme delicacy and
refinement of the internal ear,--a perfection only exercised in the
enjoyment and appreciation of the most perfect musical performances. How,
then, could either the minute incipient stages, or the final perfecting
touches of this admirable structure, have been brought about by vague,
aimless, and indefinite variations in all conceivable directions of an
organ, suitable to enable the rudest savage to minister to his necessities,
but no more?

Mr. Wallace[43] makes an analogous remark with regard to the organ of voice
in man--the human larynx. He says of singing: "The habits of savages give
no indication of how this faculty could have been developed by Natural
Selection, because it is never required or used by them. The singing of
savages is a more or less monotonous howling, and the females seldom sing
at all. Savages certainly never choose their wives for fine voices, but for
rude health, and strength, and physical beauty. Sexual selection could not
therefore have developed this wonderful power, which only comes into play
among civilized people."

Reverting once more to beauty of form and colour, there is one
manifestation of it for which no one can pretend that sexual selection can
possibly account. The instance referred to is that presented by bivalve
shell-fish.[44] Here we meet with charming tints and elegant forms and
markings of no direct use to their possessors[45] in the struggle for  {55}
life, and of no indirect utility as regards sexual selection, for
fertilization takes place by the mere action of currents of water, and the
least beautiful individual has fully as good a chance of becoming a parent
as has the one which is the most favoured in beauty of form and colour.

Again, the peculiar outline and coloration of certain orchids--notably of
our own bee, fly, and spider orchids--seem hardly explicable by any action
of "Natural Selection." Mr. Darwin says very little on this singular
resemblance of flowers to insects, and what he does say seems hardly to be
what an advocate of "Natural Selection" would require. Surely, for minute
accidental indefinite variations to have built up such a striking
resemblance to insects, we ought to find that the preservation of the
plant, or the perpetuation of its race, depends almost constantly on
relations between bees, spiders, and flies respectively and the bee,
spider, and fly orchids.[46] This process must have continued for ages
constantly and perseveringly, and yet what is the fact? Mr. Darwin tells
us, in his work on the Fertilization of Orchids, that neither the spider
nor the fly orchids are much visited by insects, while, with regard to the
bee orchid, he says, "I have never seen an insect visit these flowers." And
he shows how this species is even wonderfully and specially modified to
effect self-fertilization.

In the work just referred to Mr. Darwin gives a series of the most
wonderful and minute contrivances by which the visits of insects are
utilized for the fertilization of orchids,--structures so wonderful    {56}
that nothing could well be more so, except the attribution of their origin
to minute, fortuitous, and indefinite variation.

The instances are too numerous and too long to quote, but in his "Origin of
Species"[47] he describes two which must not be passed over. In one
(_Coryanthes_) the orchid has its lower lip enlarged into a bucket, above
which stand two water-secreting horns. These latter replenish the bucket
from which, when half-filled, the water overflows by a spout on one side.
Bees visiting the flower fall into the bucket and crawl out at the spout.
By the peculiar arrangement of the parts of the flower, the first bee which
does so carries away the pollen-mass glued to his back, and then when he
has his next involuntary bath in another flower, as he crawls out the
pollen-mass attached to him comes in contact with the stigma of that second
flower and fertilizes it. In the other example (_Catasetum_), when a bee
gnaws a certain part of the flower, he inevitably touches a long delicate
projection, which Mr. Darwin calls the antenna. "This antenna transmits a
vibration to a certain membrane, which is instantly ruptured; this sets
free a spring by which the pollen-mass is shot forth like an arrow in the
right direction, and adheres by its viscid extremity to the back of the
bee!"

Another difficulty, and one of some importance, is presented by those
communities of ants which have not only a population of sterile females, or
workers, but two distinct and very different castes of such. Mr. Darwin
believes that he has got over this difficulty by having found individuals
intermediate in form and structure[48] between the two working castes;
others may think that we have in this belief of Mr. Darwin, an example {57}
of the unconscious action of volition upon credence. A vast number of
difficulties similar to those which have been mentioned might easily be
cited--those given, however, may suffice.

There remains, however, to be noticed a very important consideration, which
was brought forward in the _North British Review_ for June 1867, p. 286,
namely, the necessity for the simultaneous modification of _many
individuals_. This consideration seems to have escaped Mr. Darwin, for at
p. 104 of his last (fifth) edition of "Natural Selection," he admits, with
great candour, that until reading this article he did not "appreciate how
rarely single variations, whether slight or strongly marked, could be
perpetuated."

The _North British Review_ (speaking of the supposition that a species is
changed by the survival of a few individuals in a century through a similar
and favourable variation) says: "It is very difficult to see how this can
be accomplished, even when the variation is eminently favourable indeed;
and still more difficult when the advantage gained is very slight, as must
generally be the case. The advantage, whatever it may be, is utterly
outbalanced by numerical inferiority. A million creatures are born; ten
thousand survive to produce offspring. One of the million has twice as good
a chance as any other of surviving; but the chances are fifty to one
against the gifted individuals being one of the hundred survivors. No doubt
the chances are twice as great against any one other individual, but this
does not prevent their being enormously in favour of _some_ average
individual. However slight the advantage may be, if it is shared by half
the individuals produced, it will probably be present in at least fifty-one
of the survivors, and in a larger proportion of their offspring; but the
chances are against the preservation of any one 'sport' (_i.e._ sudden,
marked variation) in a numerous tribe. The vague use of an imperfectly
understood doctrine of chance has led Darwinian supporters, first, to
confuse the two cases above distinguished; and, secondly, to imagine   {58}
that a very slight balance in favour of some individual sport must lead to
its perpetuation. All that can be said is that in the above example the
favoured sport would be preserved once in fifty times. Let us consider what
will be its influence on the main stock when preserved. It will breed and
have a progeny of say 100; now this progeny will, on the whole, be
intermediate between the average individual and the sport. The odds in
favour of one of this generation of the new breed will be, say one and a
half to one, as compared with the average individual; the odds in their
favour will, therefore, be less than that of their parents; but owing to
their greater number, the chances are that about one and a half of them
would survive. Unless these breed together, a most improbable event, their
progeny would again approach the average individual; there would be 150 of
them, and their superiority would be, say in the ratio of one and a quarter
to one; the probability would now be that nearly two of them would survive,
and have 200 children, with an eighth superiority. Rather more than two of
these would survive; but the superiority would again dwindle, until after a
few generations it would no longer be observed, and would count for no more
in the struggle for life than any of the hundred trifling advantages which
occur in the ordinary organs. An illustration will bring this conception
home. Suppose a white man to have been wrecked on an island inhabited by
negroes, and to have established himself in friendly relations with a
powerful tribe, whose customs he has learnt. Suppose him to possess the
physical strength, energy, and ability of a dominant white race, and let
the food and climate of the island suit his constitution; grant him every
advantage which we can conceive a white to possess over the native; concede
that in the struggle for existence his chance of a long life will be much
superior to that of the native chiefs; yet from all these admissions, there
does not follow the conclusion that, after a limited or unlimited      {59}
number of generations, the inhabitants of the island will be white. Our
shipwrecked hero would probably become king; he would kill a great many
blacks in the struggle for existence; he would have a great many wives and
children." ... "In the first generation there will be some dozens of
intelligent young mulattoes, much superior in average intelligence to the
negroes. We might expect the throne for some generations to be occupied by
a more or less yellow king; but can any one believe that the whole island
will gradually acquire a white, or even a yellow, population?"

"Darwin says that in the struggle for life a grain may turn the balance in
favour of a given structure, which will then be preserved. But one of the
weights in the scale of nature is due to the number of a given tribe. Let
there be 7000 A's and 7000 B's, representing two varieties of a given
animal, and let all the B's, in virtue of a slight difference of structure,
have the better chance of life by 1/7000 part. We must allow that there is
a slight probability that the descendants of B will supplant the
descendants of A; but let there be only 7001 A's against 7000 B's at first,
and the chances are once more equal, while if there be 7002 A's to start,
the odds would be laid on the A's. True, they stand a greater chance of
being killed; but then they can better afford to be killed. The grain will
only turn the scales when these are very nicely balanced, and an advantage
in numbers counts for weight, even as an advantage in structure. As the
numbers of the favoured variety diminish, so must its relative advantages
increase, if the chance of its existence is to surpass the chance of its
extinction, until hardly any conceivable advantage would enable the
descendants of a single pair to exterminate the descendants of many
thousands if they and their descendants are supposed to breed freely with
the inferior variety, and so gradually lose their ascendency."

Mr. Darwin himself says of the article quoted: "The justice of these
remarks cannot, I think, be disputed. If, for instance, a bird of some {60}
kind could procure its food more easily by having its beak curved, and if
one were born with its beak strongly curved, and which consequently
flourished, nevertheless there would be a very poor chance of this one
individual perpetuating its kind to the exclusion of the common form." This
admission seems almost to amount to a change of front in the face of the
enemy!

These remarks have been quoted at length because they so greatly intensify
the difficulties brought forward in this chapter. If the most favourable
variations have to contend with such difficulties, what must be thought as
to the chance of preservation of the slightly displaced eye in a sole or of
the incipient development of baleen in a whale?

SUMMARY AND CONCLUSION.

It has been here contended that a certain few facts, out of many which
might have been brought forward, are inconsistent with the origination of
species by "Natural Selection" only or mainly.

Mr. Darwin's theory requires minute, indefinite, fortuitous variations of
all parts in all directions, and he insists that the sole operation of
"Natural Selection" upon such is sufficient to account for the great
majority of organic forms, with their most complicated structures,
intricate mutual adaptations and delicate adjustments.

To this conception has been opposed the difficulties presented by such a
structure as the form of the giraffe, which ought not to have been the
solitary structure it is; also the minute beginnings and the last
refinements of protective mimicry equally difficult or rather impossible to
account for by "Natural Selection." Again the difficulty as to the heads of
flat-fishes has been insisted on, as also the origin, and at the same time
the constancy, of the limbs of the highest animals. Reference has also been
made to the whalebone of whales, and to the impossibility of           {61}
understanding its origin through "Natural Selection" only; the same as
regards the infant kangaroo, with its singular deficiency of power
compensated for by maternal structures on the one hand, to which its own
breathing organs bear direct relation on the other. Again, the delicate and
complex pedicellariæ of Echinoderms, with a certain process of development
(through a secondary larva) found in that class, together with certain
other exceptional modes of development, have been brought forward. The
development of colour in certain apes, the hood of the cobra, and the
rattle of the rattlesnake have also been cited. Again, difficulties as to
the process of formation of the eye and ear, and as to the fully developed
condition of those complex organs, as well as of the voice, have been
considered. The beauty of certain shell-fish; the wonderful adaptations of
structure, and variety of form and resemblance, found in orchids; together
with the complex habits and social conditions of certain ants, have been
hastily passed in review. When all these complications are duly weighed and
considered, and when it is borne in mind how necessary it is for the
permanence of a new variety that many individuals in each case should be
simultaneously modified, the cumulative argument seems irresistible.

The Author of this book can say that though by no means disposed originally
to dissent from the theory of "Natural Selection," if only its difficulties
could be solved, he has found each successive year that deeper
consideration and more careful examination have more and more brought home
to him the inadequacy of Mr. Darwin's theory to account for the
preservation and intensification of incipient, specific, and generic
characters. That minute, fortuitous, and indefinite variations could have
brought about such special forms and modifications as have been enumerated
in this chapter, seems to contradict not imagination, but reason. [Page 62]

That either many individuals amongst a species of butterfly should be
simultaneously preserved through a similar accidental and minute variation
in one definite direction, when variations in many other directions would
also preserve; or that one or two so varying should succeed in supplanting
the progeny of thousands of other individuals, and that this should by no
other cause be carried so far as to produce the appearance (as we have
before stated) of spots of fungi, &c.--are alternatives of an improbability
so extreme as to be practically equal to impossibility.

In spite of all the resources of a fertile imagination, the Darwinian, pure
and simple, is reduced to the assertion of a paradox as great as any he
opposes. In the place of a mere assertion of our ignorance as to the way
these phenomena have been produced, he brings forward, as their
explanation, a cause which it is contended in this work is demonstrably
insufficient.

Of course in this matter, as elsewhere throughout nature, we have to do
with the operation of fixed and constant natural laws, and the knowledge of
these may before long be obtained by human patience or human genius; but
there is, it is believed, already enough evidence to show that these as yet
unknown natural laws or law will never be resolved into the action of
"Natural Selection," but will constitute or exemplify a mode and condition
of organic action of which the Darwinian theory takes no account
whatsoever. [Page 63]

CHAPTER III.

THE CO-EXISTENCE OF CLOSELY SIMILAR STRUCTURES OF DIVERSE ORIGIN.

    Chances against concordant variations.--Examples of discordant
    ones.--Concordant variations not unlikely on a non-Darwinian
    evolutionary hypothesis.--Placental and implacental mammals.--Birds and
    reptiles.--Independent origins of similar sense organs.--The ear.--The
    eye.--Other coincidences.--Causes besides Natural Selection produce
    concordant variations in certain geographical regions.--Causes besides
    Natural Selection produce concordant variations in certain zoological
    and botanical groups.--There are homologous parts not genetically
    related.--Harmony in respect of the organic and inorganic
    worlds.--Summary and conclusion.

The theory of "Natural Selection" supposes that the varied forms and
structure of animals and plants have been built up merely by indefinite,
fortuitous,[49] minute variations in every part and in all
directions--those variations only being preserved which are directly or
indirectly useful to the individual possessing them, or necessarily
correlated with such useful variations.

[Illustration: WINGBONES OF PTERODACTYLE, BAT, AND BIRD.
(_Copied, by permission, from Mr. Andrew Murray's "Geographical
Distribution of Mammals."_)]

On this theory the chances are almost infinitely great against the
independent, accidental occurrence and preservation of two similar series
of minute variations resulting in the independent development of two
closely similar forms. In all cases, no doubt (on this same theory), _some_
adaptation to habit or need would gradually be evolved, but that       {64}
adaptation would surely be arrived at by different roads. The organic world
supplies us with multitudes of examples of similar functional results being
attained by the most diverse means. Thus the body is sustained in the air
by birds and by bats. In the first case it is so sustained by a limb in
which the bones of the hand are excessively reduced, but which is provided
with immense outgrowths from the skin--namely, the feathers of the wing. In
the second case, however, the body is sustained in the air by a limb in
which the bones of the hand are enormously increased in length, and so
sustain a great expanse of naked skin, which is the flying membrane of the
bat's wing. Certain fishes and certain reptiles can also flit and take very
prolonged jumps in the air. The flying-fish, however, takes these by means
of a great elongation of the rays of the pectoral fins--parts which cannot
be said to be of the same nature as the constituents of the wing of either
the bat or the bird. The little lizard, which enjoys the formidable name of
"flying-dragon," flits by means of a structure altogether peculiar--namely,
by the liberation and great elongation of some of the ribs which support a
fold of skin. In the extinct pterodactyles--which were _truly_ flying  {65}
reptiles--we meet with an approximation to the structure of the bat, but in
the pterodactyle we have only one finger elongated in each hand: a striking
example of how the very same function may be provided for by a modification
similar in principle, yet surely manifesting the independence of its
origin. When we go to lower animals, we find flight produced by organs, as
the wings of insects, which are not even modified limbs at all; or we find
even the function sometimes subserved by quite artificial means, as in the
aërial spiders, which use their own threads to float with in the air. In
the vegetable kingdom the atmosphere is often made use of for the
scattering of seeds, by their being furnished with special structures of
very different kinds. The diverse modes by which such seeds are dispersed
are well expressed by Mr. Darwin. He says:[50] "Seeds are disseminated {66}
by their minuteness,--by their capsule being converted into a light
balloon-like envelope,--by being embedded in pulp or flesh, formed of the
most diverse parts, and rendered nutritious, as well as conspicuously
coloured, so as to attract and be devoured by birds,--by having hooks and
grapnels of many kinds and serrated awns, so as to adhere to the fur of
quadrupeds,--and by being furnished with wings and plumes, as different in
shape as elegant in structure, so as to be wafted by every breeze."

[Illustration: SKELETON OF THE FLYING-DRAGON.
(Showing the elongated ribs which support the flitting organ.)]

Again, if we consider the poisoning apparatus possessed by different
animals, we find in serpents a perforated--or rather very deeply
channelled--tooth. In wasps and bees the sting is formed of modified parts,
accessory in reproduction. In the scorpion, we have the median terminal
process of the body specially organized. In the spider, we have a specially
constructed antenna; and finally in the centipede a pair of modified
thoracic limbs.

[Illustration: A CENTIPEDE.]

It would be easy to produce a multitude of such instances of similar ends
being attained by dissimilar means, and it is here contended that by "the
action of Natural Selection" _only_ it is so improbable as to be
practically impossible for two exactly similar structures to have ever been
independently developed. It is so because the number of possible       {67}
variations is indefinitely great, and it is therefore an indefinitely great
number to one against a similar series of variations occurring and being
similarly preserved in any two independent instances.

The difficulty here asserted applies, however, only to pure Darwinism,
which makes use _only_ of indirect modifications through the survival of
the fittest.

Other theories (for example, that of Mr. Herbert Spencer) admit the
_direct_ action of conditions upon animals and plants--in ways not yet
fully understood--there being conceived to be at the same time a certain
peculiar but limited power of response and adaptation in each animal and
plant so acted on. Such theories have not to contend against the difficulty
proposed, and it is here urged that even very complex extremely similar
structures have again and again been developed quite independently one of
the other, and this because the process has taken place not by merely
haphazard, indefinite variations in all directions, but by the concurrence
of some other and internal natural law or laws co-operating with external
influences and with Natural Selection in the evolution of organic forms.

It must never be forgotten that to admit any such constant operation of any
such unknown natural cause is to deny the purely Darwinian theory, which
relies upon the survival of the fittest by means of minute fortuitous
indefinite variations.

Amongst many other obligations which the Author has to acknowledge to
Professor Huxley, are the pointing out of this very difficulty, and the
calling his attention to the striking resemblance between certain teeth of
the dog and of the thylacine as one instance, and certain ornithic
peculiarities of pterodactyles as another.