UC-NRLF
B 3 272 D33
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SIRKfcLEY \
LIBRARY
UNIVERSITY OF
CALIFORNIA /
akwctence A Na*jr
STUDIES
ANIMAL LIFE
GEORGE HENRY LEWES,
AUTHOR OF "LIFE OF GOETHE," "THE PHYSIOLOGY OF COMMON LIFE,'
<fcc., &c.
UNI VIES ITT
NEW YORK:
HARPER & BROTHERS, PUBLISHERS,
FBANKLIN 8 Q U A B E.
1860.
81OLOGY
UBRARY
G
CONTENTS.
CHAPTER I.
Omnipresence of Life. The Microscope. An Opalina and its
Wonders. The Uses of Cilia. How our Lungs are protected
from Dust and Filings. Feeding without a Mouth or Stomach.
What is an Organ? How a complex Organism arises.
Early Stages of a Frog and a Philosopher. How the Plants
feed. Parasites of the Frog. Metamorphoses and Migrations
of Parasites. Life within Life. The budding of Animals.
A steady Bore. Philosophy of the infinitely little Page 9
CHAPTER H. .
Ponds and Rock-pools. Our necessary Tackle. Wimbledon
Common. Early Memories. Gnat Larvae. Entomostraca
and their Paradoxes. Races of Animals dispensing with the
sterner Sex. Insignificance of Males. Volvox Globator: is it
an Animal? Plants swimming like Animals. Animal Retro-
gressions. The Dytiscus and its Larva. The Dragon-fly Lar-
va. Mollusks and their Eggs. Polypes, and how to find them.
A new Polype, Hydra rubra. Nest-building Fish. Con-
tempt replaced by Reverence 39
CHAPTER m.
A garden Wall, and its Traces of past Life. Not a Breath per-
ishes. A Bit of dry Moss and its Inhabitants. The "Wheel-
bearers." Resuscitation of Rotifers: drowned into Life.
Current Belief that Animals can be revived after complete De-
siccation. Experiments contradicting the Belief. Spallanzani's
Testimony. Value of Biology as a Means of Culture. Classi-
fication of Animals: the five great Types. Criticism of Cu-
vier's Arrangement 59
Vlll CONTENTS.
CHAPTER IV.
An extinct Animal recognized by its Tooth : how came this to be
possible ? The Task of Classification. Artificial and natural
Methods. Linnaeus, and his Baptism of the Animal Kingdom :
his Scheme of Classification. What is there underlying all
true Classification ? The chief Groups. What is a Species ?
Eestatement of the Question respecting the Fixity or Variability
of Species. The two Hypotheses. Illustration drawn from the
Romance Languages. Caution to Disputants Page 86
CHAPTER V.
Talking in Beetles. Identity of Egyptian Animals with those now
existing : Does this prove Fixity of Species ? Examination of
the celebrated Argument of Species not having altered in four
thousand Years. Impossibility of distinguishing Species from
Varieties. The Affinities of Animals. New Facts proving the
Fertility of Hybrids. The Hare and the Rabbit contrasted.
Doubts respecting the Development Hypothesis. On Hypoth-
esis in Natural History. Pliny, and his Notion on the Forma-
tion of Pearls. Are Pearls owing to a Disease of the Oyster?
Formation of the Shell; Origin of Pearls. How the Chinese
manufacture Pearls 107
CHAPTER VI.
Every Organism a Colony. What is a Paradox ? An Organ is
an independent Individual and a dependent one. A Branch
of Coral. A Colony of Polypes. The Siphonophora. Uni-
versal Dependence. Youthful Aspirings. Our Interest in the
Youth of great Men. Genius and Labor. Cuvier's College
Life ; his Appearance in Youth ; his Arrival in Paris. Cuvier
and Geoffrey St.Hilaire. Causes of Cuvier's Success. One of
his early Ambitions. M. le Baron. Omnia vincit labor. Con-
clusion 128
STUDIES IN ANIMAL LIFE
CHAPTER I.
Omnipresence of Life. The Microscope. An Opalina and its
Wonders. The Uses of Cilia. How our Lungs are protected
from Dust and Filings. Feeding without a Mouth or Stomach.
What is an Organ? How a complex Organism arises.
Early Stages of a Frog and a Philosopher. How the Plants
feed. Parasites of the Frog. Metamorphoses and Migrations
of Parasites. Life within Life. The budding of Animals.
A steady Bore. Philosophy of the infinitely little.
COME with me, and lovingly study Nature, as she
breathes, palpitates, and works under myriad forms
of Life forms unseen, unsuspected, or unheeded
by the mass of ordinary men. Our course may be
through park and meadow, garden and lane, over
the swelling hills and spacious heaths, beside the
running and sequestered streams, along the tawny
coast, out on the dark and dangerous reefs, or under
dripping caves and slippery ledges. It matters lit-
tle where we go: every where in the air above,
the earth beneath, and waters under the earth we
are surrounded with Life. Avert your eyes a while
from our human world, with its ceaseless anxieties,
its noble sorrow, poignant, yet sublime, of conscious
imperfection aspiring to higher states, and contem-
A2
10 STUDIES IN ANIMAL LIFE.
plate the calmer activities of that other world with
which we are so mysteriously related. I hear you
exclaim,
"The proper study of mankind is man ;"
nor will I pretend, as some enthusiastic students
seem to think, that
"The proper study of mankind is cells;"
but agreeing with you, that man is the noblest
study, I would suggest that under the noblest there
are other problems which we must not neglect.
Man himself is imperfectly known, because the laws
of universal Life are imperfectly known. His life
forms but one grand illustration of Biology the
science of Life,* as he forms but the apex of the
animal world.
Our studies here will.be of Life, and chiefly of
those minuter or obscurer forms, which seldom at-
tract attention. In the air we breathe, in the water
we drink, in the earth we tread on, Life is every
where. Nature lives: every pore is bursting with
Life ; every death is only a new birth, every grave
a cradle. And of this we know so little, think so
little ! Around us, above us, beneath us, that great
mystic drama of creation is being enacted, and we
will not even consent to be spectators! Unless
animals are obviously useful or obviously hurtful
* The needful term Biology (from Bios, life, and logos, dis-
course) is now becoming generally adopted in England, as in Ger-
many. It embraces all the separate sciences of Botany, Zoology,
Comparative Anatomy, and Physiology.
STUDIES IN ANIMAL LIFE. 11
to us, we disregard them. Yet they are not alien,
but akin. The Life that stirs within us stirs with-
in them. We are all "parts of one transcendent
whole." The scales fall from our eyes when we
think of this ; it is as if a new sense had been vouch-
safed to us, and we learn to look at Nature with a
more intimate and personal love.
Life every where ! The air is crowded with birds
~ beautiful, tender, intelligent birds to whom life
is a song and a thrilling anxiety, the anxiety of
love. The air is swarming with insects those lit-
tle animated miracles. The waters are peopled
with innumerable forms, from the animalcule, so
small that one hundred and fifty millions of them
would not weigh a grain, to the whale, so large
that it seems an island as it sleeps upon the waves.
The bed of the seas is alive with polypes, crabs,
star-fishes, and with sand-numerous shell-animal-
cules. The rugged face of rocks is scarred by the
silent boring of soft creatures, and blackened with
countless mussels, barnacles, and limpets.
Life every where ! on the earth, in the earth,
crawling, creeping, burrowing, boring, leaping, run-
ning. If the sequestered coolness of the wood tempt
us to saunter into its checkered shade, we are sa-
luted by the murmurous din of insects, the twitter
of birds, the scrambling of squirrels, the startled
rush of unseen beasts, all telling how populous is
this seeming solitude. If we pause before a tree,
or shrub, or plant, our cursory and half-abstracted
12 STUDIES IN ANIMAL LIFE.
glance detects a colony of various inhabitants. We
pluck a flower, and in its bosom we see many a
charming insect busy at its appointed labor. We
pick up a fallen leaf, and if nothing is visible on it,
there is probably the trace of an insect larva hidden
in its tissue, and awaiting there development. The
drop of dew upon this leaf will probably contain
its animals, visible under the microscope. This
same microscope reveals that the Hood-rain sudden-
ly appearing on bread, and awakening superstitious
terrors, is nothing but a collection of minute ani-
mals (Monas prodigiosa) ; and that the vast tracts
of snow which are reddened in a single night owe
their color to the marvelous rapidity in reproduc-
tion of a minute plant (Protococcus nivalis). The
very mould which covers our cheese, our bread, our
jam, or our ink, and disfigures our damp walls, is
nothing but a collection of plants. The many-col-
ored fire which sparkles on the surface of a summer
sea at night, as the vessel plows her way, or which
drips from the oars in lines of jeweled light, is pro-
duced by millions of minute animals.
Nor does the vast procession end here. Our very
mother-earth is formed of the debris of life. Plants
and animals which have been build up its solid
fabric.* We dig downward thousands of feet be-
low the surface, and discover with surprise the
* See EHRENBERG: Microgeologie : das Erden und Felsen
schaffende Wirken des unsichtbar kleinen selbststandigen Lebcns auf
der Erde. 1854.
STUDIES IN ANIMAL LIFE. 13
skeletons of strange, uncouth animals, which roamed
the fens and struggled through the woods before
man was. Our surprise is heightened when we
learn that the very quarry itself is mainly com-
posed of the skeletons of microscopic animals ; the
flints which grate beneath our carriage wheels are
but the remains of countless skeletons. The Apen-
nines and Cordilleras, the chalk cliffs so dear to
homeward-nearing eyes these are the pyramids of
by-gone generations of atomies. Ages ago these
tiny architects secreted the tiny shells which were
their palaces ; from the ruins of these palaces we
build our Parthenons, our St. Peters, and our Lou-
vres. So revolves the luminous orb of Life ! Gen-
erations follow generations; and the Present be-
comes the matrix of the Future, as the Past was of
the Present the Life of one epoch forming the pre-
lude to a higher Life.
"When we have thus ranged air, earth, and water,
rinding every where a prodigality of living forms,
visible and invisible, it might seem as if the survey
were complete. And yet it is not so. Life cradles
within Life. The bodies of animals are little worlds,
having their own animals and plants. A celebrated
Frenchman has published a thick octavo volume
devoted to the classification and description of "The
Plants which grow on Men and Animals;"* and
many Germans have described the immense variety
* CHARLES EOBIN : Histoire Naturelle des Vegetaux Parasites
qui croissent sur VHomme et sur les Animaux Vivants. 1853.
A*
14 STUDIES IN ANIMAL LIFE.
of animals which grow on and in men and animals ;
so that science can now boast of a parasitic Flora
and Fauna. In the fluids and tissues, in the eye,
in the liver, in the stomach, in the brain, in the
muscles, parasites are found, and these parasites
have often their parasites living in them !
We have thus taken a bird's-eye view of the field
in which we may labor. It is truly inexhaustible.
We may begin where we please, we shall never
come to an end ; our curiosity will never slacken.
" And whosoe'er in youth
Has through ambition of his soul given way
To such desires, and grasp'd at such delights,
Shall feel congenial stirrings late and long."
As a beginning, get a microscope. If you can not
borrow, boldly buy one. Few purchases will yield
you so much pleasure ; and, while you are about it,
do, if possible, get a good one. Spend as little
money as you can on accessory apparatus and ex-
pensive fittings, but get a good stand and good
glasses. Having got your instrument, bear in mind
these two important trifles work by daylight, sel-
dom or never by lamplight ; and keep the unoccu-
pied eye open. With these precautions you may
work daily for hours without serious fatigue to the
eye.
Now where shall we begin? Any where will
do. This dead frog, for example, that has already
been made the subject of experiments, and is now
awaiting the removal of its spinal cord, will serve
STUDIES IN ANIMAL LIFE.
15
us as a text from which profitable lessons may be
drawn. We snip out a portion of its digestive tube,
which, from its emptiness, seems to promise little ;
but a drop of the liquid we find in it is placed on
a glass slide, covered with a small piece of very-
thin glass, and brought under the microscope. Now
look. There are several things which might occu-
py your attention, but dis-
regard them now to watch
that animalcule which you
observe swimming about.
What is it ? It is one of the
largest of the Infusoria, and
is named Opalina. When
I call this an Infusorium I
am using the language of
text-books ; but there seems
to be a growing belief among
zoologists that the Opalina
ig no t an Infusorium, but the
. .
infantile condition of some
worm -(Distoma T). However, it will not grow into
a mature worm as long as it inhabits the frog;
it waits till some pike or bird has devoured the
frog, and then, in the stomach of its new captor, it
will develop into its mature form then, and not
till then. This surprises you. And well it may;
but thereby hangs a tale, which to unfold for the
present, however, it must be postponed, because the
Opalina itself needs all our notice.
Fig. I.-OPALINA EAXAKTTM.
A, front view; R, side view mag-
16 STUDIES IN ANIMAL LIFE.
Obser.e how transparent it is, and with what
easy, undulating grace it swims about; yet this
swimmer has no arms, no legs, no tail, no backbone
to serve as a fulcrum to moving muscles nay, it has
no muscles to move with. 'Tis a creature of the
most absolute abnegations sans eyes, sans teeth,
sans every thing ; no, not sans every thing, for, as
we look attentively, we see certain currents pro-
duced in the liquid, and, on applying a higher mag-
nifying power, we detect how these currents are
produced. All over the surface of the Opalina
there are delicate hairs in incessant vibration ; these
are the cilia* They lash the water, and the animal
is propelled by their strokes, as a galley by its hund-
red oars. This is your first sight of that ciliary ac-
tion of which you have so often read, and which
you will henceforth find performing some important
service in almost every animal you examine. Some-
times the cilia act as instruments of locomotion;
sometimes as instruments of respiration, by contin-
ually renewing the current of water ; sometimes as
the means of drawing in food, for which purpose
they surround the mouth, and by their incessant
action produce a small whirlpool into which the
food is sucked. An example of this is seen in the
Yorticella. (Fig. 2.)
Having studied the action of these cilia in micro-
scopic animals, you will be prepared to understand
their office in your own organism. The lining
* From ciliwn, a hair.
STUDIES IN ANIMAL LIFE.
Fig. 2.
17
GEOTIP OP VOBTICELLA NEBUIJFEKA on a Stem of Weed, magnified.
A, one undergoing spontaneous division ; B, another spirally retracted on its
stalk ; C, one with cilia refracted ; D, a bud detached and swimming free.
membrane of your air-passages is covered with cilia,
which may be observed by following the directions
of Professor Sharpey, to whom science is indebted
for a very exhaustive description of these organs.
" To see them in motion, a portion of the ciliated
mucous membrane may be taken from a recently-
killed quadruped. The piece of membrane is to be
folded with its free, or ciliated surface outward,
placed on a slip of glass, with a little water or serum
of blood, and covered with thin glass or mica.
When it is now viewed with a power of 200 diam-
18 STUDIES IN ANIMAL LIFE.
eters or upward, a very obvious agitation will be
perceived on the edge of the fold, and this appear-
ance is caused by the moving cilia with which the
surface of the membrane is covered. Being set
close together, and moving simultaneously or in
quick succession, the cilia, when in brisk action,
give rise to the appearance of a bright transparent
fringe along the fold of the membrane, agitated by
such a rapid and incessant motion that the single
threads which compose it can not be perceived.
The motion here meant is that of the cilia them-
selves; but they also set in motion the adjoining
fluid, driving it along the ciliated surface, as is in-
dicated by the agitation of any little particles that
may accidentally float in it. The fact of the con-
veyance of fluids and other matters along the cili-
ated surface, as well as the direction in which they
are impelled, may also be made manifest by im-
mersing the membrane in fluid, and dropping on it
some finely -pulverized substance (such as charcoal
in fine powder), which will be slowly but steadily
carried along in a constant and determinate direc-
tion."*
It is an interesting fact, that while the direction
in which the cilia propel fluids and particles is gen-
erally toward the interior of the organism, it is
sometimes reversed, and, instead of beating the par-
* Quoin's Anatomy. By SHAEPEY and ELLIS. Sixth edition.
I., p. Ixxiii. See also SHARPEY'S article Cilia, in the Cyclopaedia
of Anatomy and Physiology.
STUDIES IN ANIMAL LIFE. 19
tides inward, the cilia energetically beat them back
if they attempt to enter. Fatal results would ensue
if this were not so. Our air-passages would no
longer protect the lungs from particles of sand, coal-
dust, and filings flying about the atmosphere ; on
the contrary, the lashing hairs which cover the sur-
face of these passages would catch up every parti-
cle,, and drive it onward into the lungs. Fortunate-
ly for us, the direction of the cilia is reversed, and
they act as vigilant janitors, driving back all va-
grant particles with a stern " No admittance, even
on business !" In vain does the whirlwind dash a
column of dust in our faces in vain does the air,
darkened with coal-dust, impetuously rush up the
nostrils ; the air is allowed to pass on, but the dust
is inexorably driven back. Were it not so, how
could miners, millers, iron- workers, and all the mod-
ern Tubal Cains contrive to live in their loaded
atmospheres? In a week their lungs would be
choked up.
Perhaps you will tell me that this is the case
that manufacturers of iron and steel are very subject
to consumption, and that there is a peculiar discol-
oration of the lungs which has often been observed
in coal-miners examined after death.
Not being a physican, and not intending to trouble
you with medical questions, I must still place be-
fore you three considerations, which will show how
untenable this notion is. First, although consump-
tion may be frequent among the Sheffield workmen.
20 STUDIES IN ANIMAL LIFE.
the cause is not to be sought in their breathing
filings, but in the sedentary and unwholesome con-
finement incidental to their occupation. Miners
and coal-heavers are not troubled with ,consump-
tion. Moreover, if the filings were the cause, all
the artisans would suffer, when all breathe the same
atmosphere. Secondly, while it is true that dis-
colored lungs have been observed in some miners,
it has not been observed in all or in many ; where-
as it has been observed in men not miners, not ex-
posed to any unusual amount of coal-dust. Third-
ly, and most conclusively, experiment has shown
that the coal-dust can not penetrate to the lungs.
Claude Bernard, the brilliant experimenter, tied a
bladder containing a quantity of powdered char-
coal to the muzzle of a rabbit. Whenever the an-
imal breathed, the powder within the bladder was
seen to be agitated. Except during feeding-time
the bladder was kept constantly on, so that the
animal breathed only this dusty air. If the powder
could have escaped the vigilance of the cilia and
got into the lungs, this was a good occasion. But
when the rabbit was killed and opened, many days
afterward, no powder whatever was found in the
lungs or bronchial tubes ; several patches were col-
lected about the nostrils and throat, but the cilia
had acted as a strainer, keeping all particles from
the air-tubes.
The swimming apparatus of the Opalina has led
us far away from the little animal who has been
STUDIES IN ANIMAL LIFE. 21
feeding while we have been lecturing. At the men-
tion of feeding you naturally look for the food that
is eaten, the mouth and stomach that eat. But I
hinted just now that this ethereal creature dispenses
with a stomach, as too gross for its nature, and of
course, by a similar refinement, dispenses with a
mouth. Indeed, it has no organs whatever except
the cilia just spoken of. The same is true of several
of the Infusoria, for you must know that naturalists
no longer recognize the complex organization which
Ehrenberg fancied he had detected in these micro-
scopic beings. If it pains you to relinquish the
piquant notion of a microscopic animalcule having
a structure equal in complexity to that of the ele-
phant, there will be ample compensation in the
notion which replaces it, the notion of an ascending
series of animal organisms, rising from the struc-
tureless amoeba to the complex frame of a mammal.
On a future occasion we shall see that, great as
Ehrenberg's services have been, his interpretations
of what he saw have one by one been replaced by
truer notions. His immense class of Infusoria has
been, and is constantly being, diminished; many
of his animals turn out to be plants ; many of them
embryos of worms ; and some of them belong to
the same divisions of the animal kingdom as the
oyster and the shrimp that is to say, they range
with the Mollusks and Crustaceans. In these, of
course, there is a complex organization ; but in the
Infusoria, as now understood, the organization is
22 STUDIES IN ANIMAL LIFE.
extremely simple. No one now believes the clear
spaces visible in their substance to be stomachs, as
Ehrenberg believed ; and the idea of the Polygas-
trica, or many-stomached Infusoria, is abandoned.
No one now believes the colored specs to be eyes,
because, not to mention the difficulty of conceiving
eyes where there is no nervous system, it has been
found that even the spores of some plants have
these colored specs, and they are assuredly not eyes.
If, then, we exclude the highly-organized Ratifera,
or "Wheel Animalcules," which are genuine Crus-
tacea, we may say that all Infusoria, whether they
be the young of worms or not, are of very simple
organization.
And this leads us to consider what biologists
mean by an organ : it is a particular portion of the
body set apart for the performance of some particu-
lar function. The whole process of development is
this setting apart for special purposes. The start-
ing-point of Life is a single cell that is to say, a
microscopic sac, filled with liquid and granules, and
having within it a. nucleus, or smaller sac. Paley
has somewhere remarked that in the early stages
there is no difference discernible between a frog and
a philosopher. It is very true truer than he con-
ceived. In the earliest stage of all, both the Ba-
trachian and the Philosopher are nothing but single
cells, although the one cell will develop into an
Aristotle or a Newton, and the other will get no
higher than the cold, damp, croaking animal which
STUDIES IN ANIMAL LIFE. 23
boys will pelt, anatomists dissect, and Frenchmen
eat. From the starting-point of a single cell this
is the course taken : the cell divides itself into two,
the two become four, the four eight, and so on, till
a mass of cells is formed not unlike the shape of
a mulberry. This mulberry-mass then becomes a
sac, with double envelopes or walls ; the inner wall,
turned toward the yelk, or food, becomes the assim-
ilating surface for the whole ; the outer wall, turned
toward the surrounding medium, becomes the sur-
face which is to bring frog and philosopher into
contact and relation with the external world the
Non-Ego, as the philosopher in after life will call it.
Here we perceive the first grand " setting apart," or
differentiation, has taken place ; the embryo having
an assimilating surface, which has little to do with
the external world, and a sensitive, contractile sur-
face, which has little to do with the preparation and
transport of food. The embryo is no longer a mass
of similar cells ; it is already become dissimilar, dif-
ferent, as respects its inner and outer envelope.
But these envelopes are at present uniform; one
part of each is exactly like the rest. Let us, there-
fore, follow the history of Development, and we
shall find that the inner wall gradually becomes un-
like itself in various parts, and that certain organs,
constituting a very complex apparatus of Digestion,
Secretion, and Excretion, are all one by one wrought
out of it by a series of metamorphoses or differentia-
tions. The inner wall thus passes from a simple
24 STUDIES Itf ANIMAL LIFE.
assimilating surface to a complex apparatus serving
the functions of vegetative life.
Now glance at the outer wall : from it also vari-
ous organs have gradually been wrought ; it has de-
veloped into muscles, nerves, bones, organs of sense,
and brain all these from a simple homogeneous
membrane !
With this bird's-eye view of the course of devel-
opment you will be able to appreciate the grand
law first clearly enunciated by Goethe and Yon
Baer as the law of animal life, namely, that devel-
opment is always from the general to the special,
from the simple to the complex, from the homoge-
neous to the heterogeneous, and this by a gradual
series of differentiations* Or, to put it into the
music of our deeply meditative Tennyson,
"All nature widens upward. Evermore
The simpler essence lower lies :
More complex is more perfect owning more
Discourse, more widely wise."
You are now familiarized with the words " differ-
entiation" and "development," so often met with
in modern writers, and have gained a distinct idea
of what an " organ" is, so that, on hearing of an
animal without organs, you will at once conclude
that in such an animal there has been no setting
apart of any portion of the body for special pur-
poses, but that all parts serve all purposes indis-
* GOETHE: Zur Morphologic, 1807. VON BAER: ZurEntwick-
elungsgeschichte, 1 828. Part I., p. 158.
OF THE
STUDIES IN AJSTIMAL LI^TJ JJ I V H?l S I T 3f
criminately. Here is our Qpalina,Nfop'' example,
without mouth, or stomach, or any other organ. It
is an assimilating surface in every part; in every
part a breathing, sensitive surface. Living on liquid
food, it does not need a mouth to seize, or a stomach
to digest such food. The liquid, or gas, passes
through the Opalina's delicate skin by a process
which is called endosmosis ; it there serves as food ;
and the refuse passes out again by a similar process,
called exosmosis. This is the way in which many
animals and all plants are nourished. The cell at
the end of a rootlet, which the plant sends burrow-
ing through the earth, has no mouth to seize, no
open pores to admit the liquid that it needs ; never-
theless, the liquid passes into the cell through its
delicate cell-wall, and passes from this cell to other
cells upward from the rootlet to the bud. It is in
this way, also, that the Opalina feeds: it is all-
mouth, no-mouth ; all-stomach, no-stomach. Every
part of its body performs the functions which in
more complex animals are performed by organs
specially set apart. It feeds without mouth, breathes
without lungs, and moves without muscles.
The Opalina, as I said, is a parasite. It may be
found in various animals, and almost always in the
frog. You will perhaps ask why it should be con-
sidered a parasite ? why may it not have been swal-
lowed by the frog in a gulp of water ? Certainly
nothing would have been easier. But, to remove
your doubts, I open the skull of this frog, and care-
B
26
STUDIES IN ANIMAL LIFE.
fully remove a drop of the liquid found inside,
which, on being brought under a microscope, we
shall most probably find containing some animal-
cules, especially those named Monads. These were
not swallowed. They live in the cerebro-spinal
fluid, as the Opalina lives in the digestive tube.
Nay, if we extend our researches, we shall find
that various organs have their various parasites.
Here, for instance, is a parasitic worm from the
frog's bladder. Place it
under the microscope with
a high power, and behold !
It is called Polystomum
many-mouthed, or, more
properly, many-suckered.
You are looking at the un-
der side, and will observe
six large suckers with their
starlike clasps (e), and the
horny instrument (/) with
which the animal bores its
way. At a there is anoth-
er sucker, which serves
also as a mouth ; at b you
perceive the rudiment of a
gullet, and at d the repro-
ductive organs. But pay attention to the pretty
branchings of the digestive tube (c), which ramifies
through the body like a blood-vessel.
This arrangement of the digestive tube is found
Fig. 3. POLYSTOMUM INTEGEEEI-
MTTM, magnified.
STUDIES IN ANIMAL LIFE. 27
in many animals, and is often mistaken for a system
of blood-vessels. In one sense this is correct, for
these branching tubes are carriers of nutriment, and
the only circulating vessels such animals possess ;
but the nutriment is chyme, not blood : these simple
animals have not arrived at the dignity of blood,
which is a higher elaboration of the food, fitted for
higher organisms.
Thus may our frog, besides its own marvels, af-
ford us many " authentic tidings of invisible things,"
and is itself a little colony of life. Nature is eco-
nomic as well as prodigal of space. She fills the il-
limitable heavens with planetary and starry grand-
eurs, and the tiny atoms moving over the crust of
earth she makes the homes of the infinitely little.
Far as the mightiest telescope can reach, it detects
worlds in clusters, like pebbles on the shore of in-
finitude ; deep as the microscope can penetrate, it
detects life within life, generation within genera-
tion, as if the very universe itself were not vast
enough for the energies of life !
That phrase, generation within generation, was
not a careless phrase ; it is exact. Take the tiny
insect (Aphis) which, with its companions, crowds
your rose-tree ; open it, in a solution of sugar- water,
under your microscope, and you will find in it a
young insect nearly formed ; open that young in-
sect with care, and you will find in it, also, another
young one, less advanced in its development, but
perfectly recognizable to the experienced eye ; and
28 STUDIES IN ANIMAL LIFE.
beside this embryo you will find many eggs, which
would in time become insects !
Or take that lazy water-snail (Paludina vivipara\
first made known to ^science by the great Swam-
merdamm, the incarnation of patience and exact-
ness, and you will find, as he found, forty or fifty
young snails in various stages of development ; and
you will also find, as he found, some tiny worms,
which, if you cut them open, will suffer three or
four infusoria to escape from the opening.* In your
astonishment you will ask, "Where is this to end ?
The observation recorded by Swammerdamm,
like so many others of this noble worker, fell into
neglect, but modern investigators have made it the
starting-point of a very curious inquiry. The worms
he found within the snail are now called Cercaria
sacs, because they contain the Cercarice, once classed
as Infusoria, and which are now known to be the
early forms of parasitic worms inhabiting the di-
gestive tube and other cavities of higher animals.
These Cercarice have vigorous tails, with which they
swim through the water like tadpoles, and, like tad-
poles, they lose their tails in after life. But how,
think you, did these sacs containing Cercarice get
into the water-snails? "By spontaneous genera-
tion," formerly said the upholders of that hypothe-
sis, and those who condemned the hypothesis were
forced to admit they had no better explanation. It
was a mystery which they preferred leaving unex-
* SWAMMERDAMM. Bibel der Natur, p. 75-77.
STUDIES IN ANIMAL LIFE. 29
plained rather than fly to spontaneous generation.
And they were right. The mystery has at length
been cleared up.* I will endeavor to bring togeth-
er the scattered details, and narrate the curious
story.
Under the eyelids of geese and ducks may be
constantly found a parasitic worm (of the Trematode
order), which naturalists have christened Monosto-
mum mutdbile Single-mouth, Changeable. This
worm brings forth living young, in the likeness of
active Infusoria, which, being covered with cilia,
swim about in the water as we saw the Opalina
swim. Here is a portrait of one.
Fig. 4 A, EMBBYO OP MONOSTOMTJM MUTABLLE.
B, Cercaria sac, just set free.
a, mouth; 6, pigment spots; c, sac magnified.
Each of these animalcules develops a sac in its
interior. The sac you may notice in the engraving.
* By VON SIEBOLD. See his interesting work, Ueber die Band-
und-Blasenwilrmer . It has been translated by HUXLEY, and ap-
pended to the translation of KUECHENMEISTER on Parasites, pub-
lished by the Sydenham Society.
30
STUDIES IN ANIMAL LIFE.
Having managed to get into the body of the water-
snail, the animalcule's part in the drama is at an
end. It dies, and in dying liberates the sac, which
is very comfortably housed and fed
by the snail. If you examine this sac
(Fig. 5), you will observe that it has
a mouth and digestive tube, and is,
therefore, very far from being, what its
name imports, a mere receptacle ; it is
an independent animal, and lives an
independent life. It feeds generously
Fig. 5. CEBCABIA , . . , ., -, ,
SAC. on the juices of the snail, and, -having
fed, thinks generously of the coming
generations. It was born inside the
different Stages animalcule ; why should it not in turn
give birth to children of its own ? To
found a dynasty, to scatter progeny over the boun-
teous earth, is a worthy ambition. The mysterious
agency of reproduction begins in
this sac-animal, and in a short
while a brood of Cercarice move
within it. The sac bursts, and
the brood escapes. But how is
this? The children are by no
means the " very image" of their
parent. They are not sacs, nor
in the least resembling sacs, as
you see (Fig. 6).
They have tails, and suckers,
and sharp boring instruments,
Fig. 6. CERCABIA DEVEL-
OPED.
A, mouth; B, B, B, excre-
tory organ; C, pigment
spots ; D, tail.
STUDIES 1ST ANIMAL LIFE. 31
with other organs which their parent was without.
To look at them you would as soon suspect a shrimp
to be the progeny of an oyster, as these to be the
progeny of the sac-animal. And what makes the
paradox more paradoxical is, that not only are the
Cercarios, unlike their parent, but their parent was
equally unlike its parent, the. embryo of Monosto-
mum (compare Fig. 4). However, if we pursue this
family history, we shall find the genealogy rights
itself at last, and that this Cercaria will develop in
the body of some bird into a Monostomum mutdbile
like its ancestor. Thus the worm produces an an-
imalcule, which produces a sac-animal, which pro-
duces a Cercaria, which becomes a worm exactly
resembling its great-grandfather.
One peculiarity in this history is, that while the
Monostomum produces its young in the usual way,
the two intermediate forms are produced by a process
of budding analogous to that observed in plants.
Plants, as you know, are reproduced in two ways
from the seed and from the bud. For seed-
reproduction peculiar organs are necessary; for
bud-reproduction there is no such differentiation
needed: it is simply an outgrowth. The same is
true of many animals ; they also bud like plants,
and produce seeds (eggs) like plants. I have else-
where argued that the two processes are essentially
identical, and that both are but special forms of
growth.* Not, however, to discuss so abstruse a
* Seaside Studies, p. 308 et sq.
32 STUDIES IN ANIMAL LIFE.
question here, let us merely note that the Monosto-
mum, into which the Cercaria will develop, produces
eggs, from which young will issue ; the second gen-
eration is not produced from eggs, but by internal
budding; the third generation is likewise budded
internally, but it, on acquiring maturity, will pro-
duce eggs. For this maturity, it is indispensable
that the Cercaria should be swallowed by some bird
or animal ; only in the digestive tube can it acquire
its producing condition. How is it to get there ?
The ways are many ; let us witness one :
In this watch-glass of water we have several Cer-
carice swimming about. To them we add three or
four of those darting, twittering insects which you
have seen in every vase of pond- water, and have
learned to be the larvae or early forms of the
Ephemeron. The Cercaricz cease napping the water
with their impatient tails, and commence a severe
scrutiny of the strangers. When Odry, in the riot-
ous farce Les Saltimbanques, finds a portmanteau, he
exclaims, ".Un mallei ce doit etre d moil" ("Surely
this must belong to me!") This seems to be the
theory of property adopted by the Cercaria: "An
insect! surely this belongs to me!" Accordingly
every one begins creeping over the bodies of the
Ephemera, giving an interrogatory poke with the
spine, which will pierce the first soft place it can
detect. Between the segments of the insect's armor
a soft and pierceable spot is found ; and now, lads,
to work! Onward they bore, never relaxing in
STUDIES IN ANIMAL LIFE. 33
their efforts till a hole is made large enough for
them to slip in by elongating their bodies. Once
in, they dismiss their tails as useless appendages,
and begin what is called the process of encysting
that is, of rolling themselves up into a ball, and se-
creting a mucus from their surface which hardens
round them like a shell. Thus they remain snugly
ensconced in the body of the insect, which in time
develops into a fly, hovers over the pond, and is
swallowed by some bird. The fly is digested, and
the liberated Cercaria finds itself in comfortable
quarters, its shell is broken, and its progress to ma-
turity is rapid.
Yon Siebold's description of another form of em-
igration he has observed in parasites will be read
with interest. "For a long time," he says, "the
origin of the thread-worm, known as Filaria insec-
torumj that lives in the cavity of the bodies of adult
and larval insects, could not be accounted for. Shut
up within the abdominal cavity of caterpillars, grass-
hoppers, beetles, and other insects, these parasites
were supposed to originate by spontaneous genera-
tion under the influence of wet weather or from de-
cayed food. Helminthologists (students of parasitic
worms) were obliged to content themselves with
this explanation, since they were unable to find a
better. Those who dissected these thread-worms,
and submitted them to a careful inspection, could
not deny the probability, since it was clear that they
contained no trace of sexual organs. But, on di-
B2
34: STUDIES IN ANIMAL LIFE.
recting my attention to these entozoa, I became
aware of the fact that they were not true Filarice, at
all, but belonged to a peculiar family of thread-
worms, embracing the genera of Gordius and Her-
mis. Furthermore, I convinced myself that these
parasites wander away when full grown, boring
their way from within through any soft place in
the body of their host, and creeping out through
the opening. These parasites do not emigrate be-
cause they are uneasy, or because the caterpillar is
sickly, but from that same internal necessity which
constrains the horsefly to leave the stomach of the
horse where he has been reared, or which moves
the gadfly to work its way out through the skin of
the ox. The larvae of both these insects creep forth
in order to become chrysalises, and thence to pro-
ceed to their higher and perfect condition. I have
demonstrated that the perfect, full-grown, but sex-
less thread- worms of insects are in like manner
moved by their desire to wander out of their pre-
vious homes in order to enter upon a new period
of their lives, which ends in the development of
their sex. As they leave the bodies of their hosts,
they fall to the ground and crawl away into the
deeper and moister parts of the soil. Thread-
worms found in the damp earth, in digging up gar-
dens and cutting ditches, have often been brought
to me which presented no external distinctions from
the thread- worms of insects. This suggested to me
that the wandering thread- worms of insects might
STUDIES IN" ANIMAL LIFE. 35
instinctively bury themselves in damp ground, and
I therefore instituted a series of experiments by
placing the newly-emigrated worms in flower-pots
filled with damp earth. To my delight, I soon per-
ceived that they began to bore with their heads into
the earth, and by degrees drew themselves entirely
in. For many months I kept the earth in the flow-
er-pots moderately moist, and, on examining the
worms from time to time, I found they had gradu-
ally attained their sex-development, and eggs were
deposited in hundreds. Toward the conclusion of
winter I could succeed in detecting the commencing
development of the embryos in these eggs. By the
end of spring they were fully formed, and many of
them, having left their shells, were to be seen creep-
ing about the earth. I now conjectured that these
young worms would be impelled by their instincts
to pursue a parasitic existence, and to seek out an
animal to inhabit and to grow to maturity in ; and
it seemed not improbable that the brood I had
reared would, like their parents, thrive best in the
caterpillar. In order, therefore, to induce my young
brood to immigrate, I procured a number of very
small caterpillars, which the first spring sunshine
had just called into life. For the purpose of my
experiment, I filled a watch-glass with damp earth,
taking it from among the flower-pots where the
thread-worms had wintered. Upon this I placed
several of the young caterpillars." The result was
as he expected; the caterpillars were soon bored
36 STUDIES IN ANIMAL LIFE.
into by the worms, and served them at once as food
and home.*
Frogs and parasites, worms and infusoria are
these worth the attention of a serious man ? They
have a less imposing appearance than planets and
asteroids I admit, but they are nearer to us, and ad-
mit of being more intimately known, and, because
they are thus accessible, they become more import-
ant to us. The life that stirs within us is also the
life within them. It is for this reason, as I said at
the outset, that, although man's noblest study must
always be man, there are other studies less noble,
yet not therefore ignoble, which must be pursued,
even if only with a view to the perfection of the
noblest. Many men, and these not always the ig-
norant, whose scorn of what they do not under-
stand is always ready, despise the labors which do
not obviously and directly tend to moral or political
advancement. Others there are who, fascinated by
the grandeur of Astronomy and Geology, or by the
immediate practical results of Physics and Chem-
istry, disregard all microscopic research as little bet-
ter than dilettante curiosity. But I can not think
any serious study is without its serious value to the
human race; and I know that the great problem
of Life can never be solved while we are in igno-
rance of its simpler forms. Nor can any thing be
more unwise than the attempt to limit the sphere
* VON SIEBOLD : Ueber Band-und-Blasenwurmer. Translated
by HUXLEY.
STUDIES IN ANIMAL LIFE. 37
of human inquiry, especially by applying the test
of immediate utility. All truths are related ; and,
however remote from our daily needs some partic-
ular truth may seem, the time will surely come
when its value will be felt. To the majority of our
countrymen during the Eevolution, when the con-
duct of James seemed of incalculable importance,
there would have seemed something ludicrously ab-
surd in the assertion that the newly-discovered dif-
ferential calculus was infinitely more important to
England and to Europe than the fate of all the dy-
nasties; and few things could have seemed more
remote from any useful end than this product of
mathematical genius ; yet it is now clear to every
one that the conduct of James was supremely insig-
nificant in comparison with this discovery. I do
not say that men were unwise to throw themselves
body and soul into the Eevolution ; I only say they
would have been unwise to condemn the researches
of mathematicians.
Let all who have a longing to study Nature in
any of her manifold aspects do so without regard
to the sneers or objections of men whose tastes and
faculties are directed elsewhere. From the illumi-
nation of many minds on many points Truth must
finally emerge. Man is, in Bacon's noble phrase,
the minister and interpreter of Nature ; let him be
careful lest he suffer this ministry to sink into a
priesthood, and this interpretation to degenerate
into an immovable dogma. The suggestions of
38 STUDIES IN ANIMAL LIFE.
apathy and the prejudices of ignorance have at all
times inspired the wish to close the temple against
new comers. Let us be vigilant against such sug-
gestions, and keep the door of the temple ever
open.
STUDIES IN ANIMAL LIFE. 39
CHAPTER H.
Ponds and Rock-pools. Oar necessary Tackle. Wimbledon
Common. Early Memories. Gnat Larvae. Entomostraca
and their Paradoxes. Races of Animals dispensing with the
sterner Sex. Insignificance of Males. Volvox Globator : is it
an Animal ? Plants swimming like Animals. Animal Retro-
gressions. The Dytiscus and its Larva. The Dragon-fly Lar-
va. Mollusks and their Eggs. Polypes, and how to find them.
A new Polype, Hydra rubra. Nest-building Fish. Con-
tempt replaced by Reverence.
THE day is bright with a late autumn sun ; the
sky is clear with a keen autumn wind, which lashes
our blood into a canter as we press against it, and
the cantering blood sets the thoughts into hurrying
excitement. Wimbledon Common is not far off;
its five thousand acres of undulating heather, furze,
and fern tempt us across it, health streaming in at
every step as we snuff the keen breeze. "We are
tempted also to bring net and wide-mouthed jar, to
ransack its many ponds for visible and invisible
wonders.
Ponds, indeed, are not so rich and lovely as rock-
pools ; the heath is less alluring than the coast
our dear-loved coast, with its gleaming mystery, the
sea, and its sweeps of sand, its reefs, its dripping
boulders. I admit the comparative inferiority of
ponds, but, you see, we are not near the coast, and
40 STUDIES IN ANIMAL LIFE.
the heath is close at hand. Nay, if the case were
otherwise, I should object to dwarfing comparisons.
It argues a pitiful thinness of nature (and the major-
ity in this respect are lean) when present excellence
is depreciated because some greater excellence is to
be found elsewhere. We are not elsewhere; we
must do the best we can with what is here. Be-
cause ours is not the Elizabethan age, shall we ex-
press no reverence for our great men, but reserve
it for Shakspeare, Bacon, and Ealeigh, whose tra-
ditional renown must overshadow our contempo-
raries? Not so. To each age its honor. Let us
be thankful for all greatness, past or present, and
never speak slightingly of noble work or honest
endeavor because it is not, or we choose to say it is
not, equal to something else. No comparisons, then,
I beg. If I said ponds were finer than rock-pools,
you might demur ; but I only say ponds are excel-
lent things, let us dabble in them; ponds are rich
in wonders, let us enjoy them.
And, first, we must look to our tackle. It is ex-
tremely simple. A landing-net, lined with muslin ;
a wide-mouthed glass jar, say a foot high and six
inches in diameter, but the size optional, with a bit
of string tied under the lip, and forming a loop over
the top, to serve as a handle, which will let the jar
swing without spilling the water ; a camel's-hair
brush ; a quinine bottle, or any wide-mouthed phi-
al, for worms and tiny animals which you desire to
keep separated from the dangers and confusions of
STUDIES IN ANIMAL LIFE. 41
the larger jar; and when to these a pocket lens is
added, our equipment is complete.
As we emerge upon the common and tread its
springy heather, what a wild wind dashes the hair
into our eyes, and the blood into our cheeks ! and
what a fine sweep of horizon lies before us ! The
lingering splendors and the beautiful decays of au-
tumn vary the scene, and touch it with a certain
pensive charm. The ferns mingle harmoniously
their rich browns with the dark green of the furze,
now robbed of its golden summer glory, but still
pleasant to the eye and exquisite to memory. The
gaunt wind-mill on the rising ground is stretching
its stiff, starred arms into the silent air, a land-
mark for the wanderer a land-mark, too, for the
wandering mind, since it serves to recall the dim
early feelings and sweet broken associations of a
childhood when we gazed at it with awe, and listen-
ed to the rushing of its mighty arms. Ah ! well
may the mind with the sweet insistance of sadness
linger on those scenes of the irrecoverable past, and
try, by lingering there, to feel that it is not wholly
lost, wholly irrecoverable, vanished forever from the
Life which, as these decays of autumn and these
changing trees too feelingly remind us, is gliding
away, leaving our cherished ambitions still unful-
filled, and our deeper affections still but half ex-,
pressed. The vanishing visions of elapsing life
bring with them thoughts which lie too deep for
tears, and this wind-mill recalls such visions by
42 STUDIES IN ANIMAL LIFE.
the subtle laws of association. Let us go toward it,
and stand once more under its shadow. See the in-
telligent and tailless sheep-dog which bounds out at
our approach, eager and minatory ; now his quick
eye at once recognizes that we are neither tramps
nor thieves, and he ceases barking to commence a
lively interchange of sniffs and amenities with our
Pug, who seems also glad of a passing interchange
of commonplace remarks. While these dogs travel
over each other's minds, let us sun ourselves upon
this bench, and look down on the embrowned val-
ley, with its gipsy encampment, or abroad on the
purple Surrey hills, or the varied-tinted trees of
Combe Wood and Richmond Park. There are not
many such prospects so near London. But, in
spite of the sun, we must not linger here : the wind
is much too analytical in its remarks ; and, more-
over, we came out to hunt.
Here is a pond with a mantling surface of green
promise. Dip the jar into the water. Hold it now
up to the light, and you will see an immense varie-
ty of tiny animals swimming about. Some are
large enough to be recognized at once; others re-
quire a pocket lens, unless familiarity has already
enabled you to infer the forms you can not distinct-
ly see. Here (Fig. 7) are two larvae (or grubs) of
the common gnat. That large-headed fellow (A)
bobbing about with such grotesque movements is
very near the last stage of his metamorphosis,
and to-morrow, or the next day, you may see him
STUDIES IN ANIMAL LIFE.
Fig. 7. LABV./E OP THE GNAT in two different stages of development
(magnified).
cast aside this mask (larva means a mask), and
emerge a perfect insect. The other (B) is in a
much less matured condition, but leads an active
predatory life, jerking through the water, and fast-
ening to the stems of weed or sides of the jar by
means of the tiny hooks at the end of its tail. The
hairy appendage forming the angle is not another
tail, but a breathing apparatus.
Observe, also, those grotesque Entomostraca*
popularly called "water-fleas," although, as you
perceive, they have little resemblance in form or
manners to our familiar (somewhat too familiar)
bed-fellows. This (Fig. 8) is a Cyclops, with only
one eye in the centre of its forehead, and carrying
two sacs, filled with eggs, like panniers. You ob-
* Entomostraca (from entomos, an insect, and ostracon, a shell)
are not really insects, but belong to the same large group of ani-
mals as the lobster, the crab, or the shrimp i. e., crustaceans.
44
STUDIES IN ANIMAL LIFE.
serve he has no legs ; or,
rather, legs and arms are
Fig. 8 CYCLOPS.
a, large antennae ; 6, smaller do. ;
c, egg-sacs (magnified).
Fig. 9. DAPHNIA.
a, pulsatile sac, or heart ; 6, eggs ;
c, digestive tube (magnified).
hoisted up to the head, and become antennae (or
feelers). Here (Fig. 9) is a Daphnia, grotesque
enough, throwing up his arms in astonished awk-
wardness, and keeping
his legs actively at work
inside the shell as res-
pirators, in fact. Here
(Fig. 10) is a Eurycer-
cus, less grotesque, and
with a much smaller eye.
Talking of eyes, there is
Fig. 10. EUEYCEKCUS.
a, heart ; &, eggs ; c, digestiv<
(magnified).
tube
one of these Entomos-
traca, named Polyphemus, whose head is all eye;
and another, named Caligus, who has no head at all.
Other paradoxes and wonders are presented by this
interesting group of animals ;* but they all sink
* The student will find ample information in BAIRD'S British
Entomostraca, published by the Kay Society.
STUDIES IN ANIMAL LIFE. 45
into insignificance beside the paradox of the ama-
zonian entomostracon, the Apus a race which dis-
penses with masculine services altogether, a race of
which there are no males !
I well remember the pleasant evening on which
I first made the personal acquaintance of this ama-
zon. It was at Munich, and in the house of a cele-
brated naturalist, in whose garden an agreeable as-
semblage of poets, professors, and their wives saun-
tered in the light of a setting sun, breaking up into
groups and tetes-d-tetes, to re-form into larger groups.
We had taken coffee under the branching coolness
of trees, and were now loitering through the brief
interval till supper. Our host had just returned
from an expedition of some fifty miles to a particu-
lar pond, known to be inhabited by the Apus. He
had made this journey because the race, although
prolific, is rare, and is not to be found in every spot.
For three successsive years had he gone to the same
pond in quest of the male ; but no male was to be
found among thousands of egg-bearing females,
some of which he had brought away with him, and
was showing us. We were amused to see them
swimming about, sometimes on their backs, using
their long oars, sometimes floating, but always in-
cessantly agitating the water with their ten pairs
of breathing legs ; and the ladies, gathered round
the jar, were hugely elated at the idea of animals
getting rid altogether of the sterner sex clearly a
useless encumbrance in the scheme of things !
46 STUDIES IN ANIMAL LIFE.
The fact that no male Apus has yet been found
is not without precedent. Leon Dufour, the cele-
brated entomologist, declares that he never found
the male of the gall insect (Diplolepis gallce tinctorice),
though he has examined thousands : they were all*
females, and bore well-developed eggs on emerging
from the gall-nut in which their infancy had pass-
ed. In two other species of gall insect Cynips di-
visa and Cynips folii Hartig says he was unable to
find a male ; and he examined about thirteen thou-
sand. Brongniart never found the male of another
entomostracon (Limnadia gigas), nor could Jurine
find that of our Polyphemus. These negatives
prove, at least, that if the males exist at all, they
must be excessively rare, and their services can be
dispensed with ; a conclusion which becomes accept-
able when we learn that bees, plant-lice (Aphides),
and our grotesque friend Daphnia (Fig. 9) lay eggs
which may be reared apart, will develop into fe-
males, and these will produce eggs which will in
turn produce other females, and so on, generation
after generation, although each animal be reared in
a vessel apart from all others.
While on this subject, I can not forbear making
a reflection. It must be confessed that our sex cuts
but a poor figure in some great families. If the
male is in some families grander, fiercer, more splen-
did, and more highly endowed than the female, this
occasional superiority is more than counterbalanced
by the still greater inferiority of the sex in other
OF THE
STUDIES IN ANIMAL LfIT Jjf J "^ H51 5
families. The male is often but a contemptible
partner, puny in size, insignificant in powers, stint-
ed even of a due allowance of organs. If the pea-
cock and the pheasant swagger in greater splendor,
what a pitiful creature is the male falcon I no fal-
coner will look at him. And what is the drone
compared with the queen bee, or even with the
workers ? What figure does the male spider make
beside his large and irascible female, who not un-
frequently eats him ? Nay, worse than this, what
can be said for the male Eotifer, the male Barnacle,
the male Lernaea gentlemen who can not even
boast of a perfect digestive apparatus, sometimes
not of a digestive organ at all ? Nor is this mea-
greness confined to the digestive system only. In
some cases, as in some male Kotifers, the usual or-
gans of sense and locomotion are wanting ;* and in
a parasitic Lernaea, the degradation is moral as well
as physical : the female lives in the gills of a fish,
sucking its juices, and the ignoble husband lives as
a parasite upon her !
But this digression is becoming humiliating, and
meanwhile our hands are getting benumbed with
cold. In spite of that, I hold the jar up to the
light, and make a background of my forefingers, to
throw into relief some of the transparent animals.
Look at those green crystal spheres sailing along
v * Compare GEGENBAUR: Gnmdzuge der vergldchende Anato-
rnie, 1859, p. 229 und 269 ; also LEYDIG iiber Hydatina senta, in
Miller's Arckiv, 1857, p. 411.
48 STUDIES IN ANIMAL LIFE.
Fig. 11. VOLVOX GLOBATOR, with eight volvoces
inclosed (magnified).
with slow revolving motion, like planets revolving
through, space, except that their orbits are more ec-
centric. Each of these spheres is a Volvox globator.
Under the microscope it looks like a crystalline
sphere, studded with bright green specks, from each
of which arise two cilia (hairs), serving as oars to
row the animal through the water. The specks are
united by a delicate net-work, which is not always
visible, however. Inside this sphere is a fluid, in
which several dark green smaller spheres are seen
revolving, as the parent sphere revolved in the wa-
ter. Press this Yolvox gently under your com-
pressorium, or between the two pieces of glass, and
you will see these internal spheres, when duly mag-
nified, disclose themselves as identical with their
parent ; and inside them smaller Volvoces are
seen. This is one of the many illustrations of life
within life, of which something was said in the last
chapter.
STUDIES IN ANIMAL LIFE. 49
Nor is this all. Those bright green specks which
stud the surface, if examined with high powers, will
turn out to be, not specks, but animals,* and, as Eh-
renberg believes (though the belief is but little
shared), highly organized animals, possessing a
mouth, many stomachs, and an eye. It is right to
add that not only are microscopists at variance with
Ehrenberg on the supposed organization of these
specks, but the majority deny that the Yolvox itself
is an animal. Yon Siebold in Germany, and Pro-
fessor George Busk and Professor Williamson in
England, have argued with so much force against
the animal nature of the Yolvox, which they call a
plant, that in most modern works you will find this
opinion adopted. But the latest of the eminent au-
thorities on the subject of Infusoria, in his magnifi-
cent work just published, returns to the old idea
that the Yolvox is an animal after all, although of
very simple organization.f
The dispute may perhaps excite your surprise.
You are perplexed at the idea of a plant (if plant it
be) moving about, swimming with all the vigor and
dexterity of an animal, and swimming by means of
animal organs, the cilia. But this difficulty is one
of our own creation. We first employ the word
* To avoid the equiyoque of calling the parts of an animal,
\vhich are capable of independent existence, by the same term as
the whole mass, we may adopt HUXLEY'S suggestion, and call all
such individual parts zooids instead of animals. DUGES suggested
zoonites in the same sense. Sur la Conformite Organique, p. 13.
i STEIN : Der Organismus der Infusionsthiere, 1859, p. 36-38.
c
50 STUDIES IN ANIMAL LIFE.
plant to designate a vast group of objects which
have no powers of locomotion, and then ask, with
triumph, How can a plant move? But we have
only to enlarge our knowledge of plant-life to see
that locomotion is not absolutely excluded from it;
for many of the simpler plants Confervse and Al-
gae can and do move spontaneously in the early
stages of their existence : they escape from their
parents as free swimming rovers, and do not settle
into solid and sober respectability till later in life.
In their roving condition they are called, improper-
ly enough, " zoospores,"* and once gave rise to the
opinion that they were animals in infancy, and be-
came degraded into plants as their growth went on.
But locomotion is no true mark of animal-nature,
neither is fixture to one spot the true mark of plant-
nature. Many animals (Polypes, Polyzoa, Barna-
cles, Mussels, etc.), after passing a vagabond youth,
" settle" once and forever in maturer age, and then
become as fixed as plants. Nay, human animals
not unfrequently exhibit a somewhat similar me-
tempsychosis, and make up for the fitful capricious-
ness of wandering youth by the steady severity of
their application to business when width of waist-
coat and smoothness of cranium suggest a sense of
their responsibilities.
Whether this loss of locomotion is to be regard-
ed as a retrogression on the part of the plant or
animal which becomes fixed, may be questioned;
* Zoospores, from zoon, an animal, and s/>oros, a seed.
STUDIES IN ANIMAL LIFE. 51
but there are curious indications of positive retro-
gression from a higher standard in the metamor-
phoses of some animals. Thus the beautiful marine
worm Terebella, which secretes a tube for itself, and
lives in it, fixed to the rock or oyster-shell, has in
early life a distinct head, eyes, and feelers ; but in
growing to maturity it loses all trace of head, eyes,
and even of feelers, unless the beautiful tuft of
streaming threads which it waves in the water be
considered as replacing the feelers. There are the
Barnacles, too, which in the first stage of their ex-
istence have three pairs of legs, a very simple single
eye, and a mouth furnished with a proboscis. In
the second stage they have six pairs of legs, two
compound eyes complex in structure, two feelers,
but no mouth. In the third, or final stage, their
legs are transformed into prehensile organs, they
have recovered a mouth, but have lost their feelers,
and their two complex eyes are degraded to a single
and very simple eye-spot.
But, to break up these digressions, let us try a
sweep with our net. We skim it along the surface,
and draw up a quantity of duckweed, dead leaves,
bits of stick, and masses of green thread of great
fineness, called Conferva by botanists. The water
runs away, and we turn over the mass. Here is a
fine water-beetle, called the " Water-tiger," from its
ferocity (Fig. 12). You would hardly suspect that
the slim, big-headed, long-tailed Water-tiger would
grow into the squat, small-headed, tailless beetle ;
52
STUDIES IN ANIMAL LIFE.
Fig. 12. WATEE BEETLE and its larva.
nor would you imagine that this Water-tiger would
be so "high fantas-
tical" as to breathe
by his tail. Yet he
does both, as you will
find if you watch
him in your aqua-
rium.
Continuing our
search, we light up-
on the fat, sluggish,
ungraceful larva of
the graceful and bril-
liant Dragon-fly, the
falcon of insects (Fig.
13). He is useful
for dissection, so pop
Fig.i3.-DBAGON-FLYL AR v, E : him in. Among the
A, ordinary aspect; B, with the huge nipper-
like jaw extended. dead leaves you per-
STUDIES IN ANIMAL LIFE.
53
ceive several small leeches, and flat oval Plana-
rice, white and brown ; and here also is a jelly-
like mass, of pale yellow color, which we know
to be a mass of eggs deposited by some shell-
fish; and, as there are few objects of greater inter-
est than an egg in course of development, we pop
the mass in. Here (Fig. 14) are two mollusks, Lim-
Fig. 14 A, LIMN^US STAGNALIS, or Water-snail.
B, PLANOBBIS.
nceus and Planorbis, one of which is probably the
parent of those eggs.
And here is one which
lays no eggs, but brings
forth its young alive : it
is the Paludina vivipara
(Fig. 15), of which we
learned some interest-
ing details last month. Fig. IS. PALCDIHA VIVH-AKA.
54 STUDIES IN ANIMAL LIFE.
Scattered over the surface of the net and dead leaves
are little dabs of dirty -looking jelly some of them,
instead of the dirty hue, are almost blood-red. Ex-
perience makes me aware that these dirty dabs are
certainly Polypes the Hydra fusca of systematists.
I can't tell how it is I know them, nor how you may
know them again. The power of recognition must
be acquired by familiarity ; and it is because men
can't begin with familiarity, and can't recognize these
Polypes without it, that so few persons really ever
see them. But the familiarity may be acquired by a
very simple method. Make it a rule to pop every
unknown object into your wide-mouthed phial. In
the water it will probably at once reveal its nature :
if it be a Polype, it will expand its tentacles ; if not,
you can identify it at leisure on reaching home by
the aid of pictures and descriptions. See, as I drop
one of these into the water, it at once assumes the well-
known shape of the Polype. And now we will see
what these blood-red dabs may be ; in spite of their
unusual color, I can not help suspecting them to be
Polypes also. Give me the camel-hair brush. Gen-
tly the dab is removed, and transferred to the phial.
Shade of Trembley ! it is a Polype !* Is it possible
that this discovery leaves you imperturbable, even
* TREMBLEY, in his admirable work, Memoires pour servir a
Vkistoire dune genre de Polypes deau dome, 1744, furnished science
with the fullest and most accurate account of fresh-water Polypes ;
but it is a mistake to suppose that he was the original discoverer of
this genus : old LEUWENHOEK had been before him.
STUDIES IN ANIMAL LIFE. 55
when I assure you it is of a species hitherto unde-
scribed in text-books ? Now don't be provokingly
indifferent ! rouse yourself to a little enthusiasm,
and prove that you have something of the natural-
ist in you by delighting in the detection of a new
species. "You didn't know that it was new?"
That explains your calmness. There must be a
basis of knowledge before wonder can be felt
wonder being, as Bacon says, " broken knowledge."
Learn, then, that hitherto only three species of
fresh-water Polypes have been described: Hydra
viridis, Hydra fusca, and Hydra grisea. We have
now a fourth to swell the list; we will christen it
Hydra rubra, and be as modest in our glory as we
can. If any one puts it to us whether we seriously
attach importance, to such trivialities as specific dis-
tinctions resting solely upon color or size, we can
look profound, you know, and repudiate the charge.
But this is a public and official attitude. In pri-
vate we can despise the distinctions established by
others, but keep a corner of favoritism for our own.*
I remember once showing a bottle containing
Polypes to a philosopher, who beheld them with
great calmness. They appeared to him as insignifi-
* The editors of the Annals of Natural History append a note to
the account I sent them of this new Polype, from which it appears
that Dr. Gray found this very species, and apparently in the. same
spot, nearly thirty years ago. But the latest work of authority,
VAN DER HOVEN'S Handbook of Zoology, only enumerates the three
species.
56 STUDIES IN ANIMAL LIFE.
cant as so many stems of duckweed ; and, lest you
should be equally indifferent, I will at once inform
you that these creatures will interest you as much
as any that can be found in ponds, if you take the
trouble of studying them. They can be cut into
many pieces, and each piece will grow into a per-
fect Polype ; they may be pricked or irritated, and
the irritated spot will bud a young Polype, as a
plant buds; they may be turned inside out, and
their skin will become a stomach, their stomach a
skin. They have acute sensibility to light (toward
which they always move), and to the slightest touch;
yet not a trace of a nervous tissue is to be found in
them. They have powers of motion and locomo-
tion, yet their muscles are simply a network of
large contractile cells. If the water in which they
are kept be not very pure, they will be found in-
fested with parasites ; and quite recently I have no-
ticed an animal or vegetal parasite I know not
which forming an elegant sort of fringe to the
tentacles ; clusters of skittle-shaped bodies, too en-
tirely transparent for any structure whatever to tie
made out, in active agitation, like leaves fluttering
on a twig. Some day or other we may have occa-
sion to treat of the Polypes in detail, and to narrate
the amusing story of their discovery ; but what has
already been said will serve to sharpen your atten-
tion, and awaken some curiosity in them.
Again and again the net sweeps among the weed
or dredges the bottom of the pond, bringing up mud,
STUDIES IN ANIMAL LIFE. 57
stones, sticks, with a fish, worms, mollusks, and tri-
tons. The fish we must secure, for it is a stickle-
back a pretty and interesting inhabitant of an
aquarium, on account of its nest-building propensi-
ties. We are surprised at a fish building a nest
and caring for its young like the tenderest of birds
(and there are two other fishes, the Goramy and the
Hassar, which have this instinct); but why not a
fish as well as a bird? The catfish swims about
in company with her young, like a proud hen with
her chickens, and the sunfish hovers for weeks over
her eggs, protecting them against danger.
The wind is so piercing, and my fingers are so
benumbed, I can scarcely hold the brush. More-
over, continual stooping over the net makes the
muscles ache unpleasantly, and suggests that each
cast shall be the final one. But somehow I have
made this resolution and broken it twenty times :
either the cast has been unsuccessful, and one is
provoked to try again, or it is so successful that, as
Tappetit vient en mangeant, one is seduced again.
Yery unintelligible this would be to the passers-
by, who generally cast contemptuous glances at us
when they find we are not fishing, but are only re-
moving nothings into a glass jar. One day an
Irish laborer stopped and asked me if I were fish-
ing for salmon. I quietly answered "Yes." He
drew near. I continued turning over the weed, oc-
casionally dropping an invisible thing into the wa-
ter. At last a large yellow-bellied Triton was
C2
58 STUDIES IN ANIMAL LIFE.
dropped in. He begged to see it; and, seeing at
the same time how alive the water was with tiny
animals, became curious, and asked many questions.
I went on with my work ; his interest and curiosity
increased ; his questions multiplied ; he volunteered
assistance ; and remained beside me till I prepared
to go away, when he said seriously, "Och! then,
and it's a fine thing to be able to name all God's
creatures." Contempt had given place to rever-
ence ; and so it would be with others, could they
check the first rising of scorn at what they do not
understand, and patiently learn what even a road-
side pond has of Nature's wonders.
STUDIES IN ANIMAL LIFE. 69
CHAPTER HI.
A garden Wall, and its Traces of past Life. Not a Breath per-
ishes. A Bit of dry Moss and its Inhabitants. The "Wheel-
bearers." Resuscitation of Rotifers: drowned into Life.
Current Belief that Animals can be revived after complete De-
siccation. Experiments contradicting the Belief. Spallanzani's
Testimony. Value of Biology as a Means of Culture. Classi-
fication of Animals : the five great Types. Criticism of Cu-
vier's Arrangement.
PLEASANT, both to eye and mind, is an old gar-
den wall, dark with age, gray with lichens, green
with mosses* of beautiful hues and fairy elegance of
form ; a wall shutting in some sequestered home,
far from "the din of murmurous cities vast;" a
home where, as we fondly, foolishly think, Life
must needs throb placidly,. and all its tragedies and
pettinesses be unknown. As we pass alongside this
wall, the sight of the overhanging branches sug-
gests an image of some charming nook; or our
thoughts wander about the wall itself, calling up
the years during which it has been warmed by the
sun, chilled by the night airs and the dews, and
dashed against by the wild winds of March, all of
which have made it quite another wall from what
it was when the trowel first settled its bricks. The
old wall has a past, a life, a story ; as Wordsworth
60 STUDIES IN ANIMAL LIFE.
finely says of the mountain, it is " familiar with for-
gotten years." Not only are there obvious traces
of age in the crumbling mortar and the battered
brick, but there are traces, not obvious except to
the inner eye, left by every ray of light, every rain-
drop, every gust. Nothing perishes. In the won-
drous metamorphosis momently going on every
where in the universe, there is change, but no loss.
Lest you should imagine this to be poetry, and
not science, I will touch on the evidence that every
beam of light, or every breath of air which falls
upon an object, permanently affects it. In photog-
raphy we see the effect of light very strikingly ex-
hibited; but perhaps you wilt object that this proves
nothing more than that light acts upon an iodized
surface. Yet, in truth, light acts upon, and more or
less alters the structure of every object on which it
falls. Nor is this all. If a wafer be laid on a sur-
face of polished metal, which is then breathed upon,
and if, when the moisture of the breath has evapo-
rated, the wafer be shaken off, we shall find that the
whole polished surface is not as it was before, al-
though our senses can detect no difference ; for if
we breathe again upon it, the surface will be moist
every where except on the spot previously shelter-
ed by the wafer, which will now appear as a spec-
tral image on the surface. Again and again we
breathe, and the moisture evaporates, but still the
spectral wafer reappears. This experiment suc-
ceeds after a lapse of many months if the metal be
STUDIES IN ANIMAL LIFE. 6i
carefully put aside where its surface can not be dis-
turbed. If a sheet of paper on which a key has
been laid be exposed for some minutes to the sun-
shine, and then instantaneously viewed in the dark,
the key being removed, a fading spectre of the key
will be visible. Let this paper be put aside for
many months where nothing can disturb it, and
then in darkness be laid on a plate of hot metal,
the spectre of the key will again appear. In the
case of bodies more highly phosphorescent than
paper, the spectres of many different objects which
may have been laid on in succession will, on warm-
ing, emerge in their proper order.*
This is equally true of our bodies and our minds.
We are involved in the universal metamorphosis.
Nothing leaves us wholly as it found us. Every
man we meet, every book we read, every picture
or landscape we see, every word or tone we hear,
mingles with our being and modifies it. There are
cases on record of ignorant women, in states of in-
sanity, uttering Greek and Hebrew phrases, which
in past years they had heard their masters utter,
without, of course, comprehending them. These
tones had long been forgotten ; the traces were so
faint that under ordinary conditions they were 'in-
visible ; but the traces were there, and in the in-
tense light of cerebral excitement they started into
prominence, just as the spectral image of the key
started into sight on the application of heat. It is
* DRAPER : Human Physiology, p. 288.
62 STUDIES IN ANIMAL LIFE.
thus with all the influences to which we are sub-
jected.
If a garden wall can lead our vagabond thoughts
into such speculations as these, surely it may also
furnish us with matter for our Studies in Animal
Life. Those patches of moss must be colonies.
Suppose we examine them. I pull away a small
bit, which is so dry that the dust crumbles at a
touch ; this may be wrapped in a piece of paper
dirt and all and carried home. Get the micro-
scope ready, and now attend.
I moisten a fragment of this moss with distilled
water. Any water will do as well, but the use of
distilled water prevents your supposing that the
animals you are about to watch were brought in it,
and were not already in the moss. I now squeeze
the bit between my fingers, and a drop of the con-
tained water somewhat turbid with dirt falls on
the glass slide, which we may now put on the mi-
croscope stage. A rapid survey assures us that
there is no animal visible. The moss is squeezed
again, and this time little yellowish bodies of an
irregular oval are noticeable among the particles
of dust and moss. Watch one of these, and pres-
ently you will observe a slow bulging at one end,
and then a bulging at the other end. The oval
has elongated itself into a form not unlike that-
of a fat caterpillar, except that there is a tapering
at one end. Now a forked tail is visible ; this fixes
on to the glass, while the body swings to and fro.
STUDIES IN ANIMAL LIFE.
Now the head is drawn in as if it were swallowed
and suddenly in its place are unfolded two broad
membranes, having each a circle of waving cilia.
The lifeless oval has become a living animal ! You
have assisted at a resuscitation, not from death by
drowning, but by drying: the animal has been
drowned into life ! The unfolded membranes, with
their cilia, have so much the appearance of wheels
that the name of " "Wheel-bearer" (Rotifera) or
" Wheel Animalcule" has been given to the animal.
Fig. 16. ROTTFEB VULGABIB.
A, with the wheels drawn in (at c). B, with the wheels expanded; 6, eye
ppots; e, jaw and teeth; /, alimentary canal; gr, embryo; A, embryo further
developed : ?', water- vascular system ; fc, vent.
64 STUDIES IN ANIMAL LIFE.
The Eotifera (also, and more correctly, called
Rotatoria) form an interesting study. Let us glance
at their organization :
There are many different kinds of Kotifers, vary-
ing very materially in size and shape, the males, as
was stated in the last chapter, being more imper-
fectly organized than the females. They may be
seen either swimming rapidly through the water
by means of the vibratile cilia called " wheels," be-
cause the optical effect is very much that of a
toothed wheel, or crawling along the side of the
glass, fastening to it by the head, and then curving
the body till the tail is brought up to the spot,
which is then fastened on by the tail, and the head
is set free. They may also be seen fastened to a
weed, or the glass, by the tail, the body waving to
and fro, or thrusting itself straight out, and setting
the wheels in active motion. In this attitude the
aspect of the jaws is very striking. Leuwenhoek
mistook it for the pulsation of a heart, which its in-
cessant rhythm much resembles. The tail and the
upper part of the body have a singular power of
being drawn out or drawn in, like the tube of a
telescope. There is sometimes a shell or carapace,
but often the body is covered only with a smooth
firm skin, which, however, presents decided indica-
tions of being segmented.
The first person who described these Eotifers was
the excellent old Leuwenhoek,* and his animals
* LEUWENHOEK: Select Works, ii., p. 210. His figures, how-
ever, are very incorrect.
STUDIES IN ANIMAL LIFE. t>5
were got from the gutter of a house-top. Since
then they have been minutely studied, and have
been shown to" be, not Infusoria, as Ehrenberg im-
agined, but Crustacea.* Your attention is request-
ed to the one point which has most contributed to
the celebrity of these creatures their power of re-
suscitation. Leuwenhoek described what you
have just witnessed, namely the slow resuscitation
of the animal (which seemed as dry as dust, and
might have been blown about like any particle of
dust) directly a little moisture was brought to it.
Spallanzani startled the world with the announce-
ment that this process of drying and moistening
of killing and reviving could be repeated fifteen
times in s accession; so that the Kotifer, whose nat-
ural term of life is about eighteen days, might, it
was said, be dried and kept for years, and at any
time revived by moisture. That which seems now
no better than a grain of dust will suddenly awaken
to the energetic life of a complex organism, and
may again be made as dust by the evaporation of
the water.
This is very marvelous; so marvelous that a
mind trained in the cultivated caution of science
will demand the evidence on which it is based.
Two months ago I should have dismissed the doubt
with the assurance that the evidence was ample and
* See LEYDIG : Ueber den Bau und die systematische Stellung
der Rdderthiere, in SIEBOLD und KOLLIKER'S Zeitschrift, vi., and
Ueber Hydatina Senta, in MULLER'S Arr.hiv, 1857.
66 STUDIES IN ANIMAL LIFE.
rigorous, and the fact indisputable; for not only
had the fact been confirmed by the united experi-
ence of several investigators, it had stood the test
of very severe experiment. Thus, in 1842, M. Do-
yere published experiments which seemed to place
it beyond skepticism. Under the air-pump he set
some moss, together with vessels containing sul-
phuric acid, which would absorb every trace of
moisture. After leaving the moss thus for a week,
he removed it into an oven, the temperature of which
was raised to 300 Fahrenheit. Yet even this treat-
ment did not prevent the animals from resuscitating
when water was added.
In presence of testimony like this, doubt will seem
next to impossible. Nevertheless, my own experi-
ments leave me no choice but to doubt. Not hav-
ing witnessed M. Doyere's experiment, I ani not
prepared to say wherein its fallacy lies ; but that
there is a fallacy seems to me capable of decisive
proof. In M. Pouchet's recent work* I first read a
distinct denial of the pretended resuscitation of the
Eotifers ; this denial was the more startling to me,
because I had myself often witnessed the reawaken-
ing of these dried animals. Nevertheless, whenev-
er a doubt is fairly started, we have not done jus-
tice to it until we have brought it to the test of ex-
periment; accordingly, I tested this, and quickly
came upon what seems to me the source of the gen-
* POUCHET : Heterogenie, ou Traite de la Generation Spontanee,
1859, p. 453.
STUDIES IN ANIMAL LIFE. 67
eral misconception. Day after day experiments
were repeated, varied, and controlled, and with re-
sults so unvarying that hesitation vanished ; and as
some of these experiments are of extreme simplici-
ty, you may verify what I say with little trouble.
Squeeze a drop from the moss, taking care that
there is scarcely any dirt in it ; and, having ascer-
tained that it contains Eotifers or Tardigrades,*
alive and moving, place the glass slide under a bell-
glass, to shield it from currents of air, and there al-
low the water to evaporate slowly, but completely,
by means of chloride of calcium or sulphuric acid
placed under the bell-glass; or, what is still sim-
pler, place a slide with the live animals on the man-
telpiece when a fire is burning in the grate. If on
the day following you examine this perfectly dry
glass, you will see the contracted bodies of the Eo-
tifers, presenting the aspect of yellowish oval bodies;
but attempt to resuscitate them by the addition of
a little fresh water, and you will find that they do
not revive, as they revived when dried in the moss ;
they sometimes swell a little, and elongate them-
selves, and you imagine this is a commencement of
resuscitation; but continue watching for two or
-three days, and you will find it goes no further.
* The Tardigrade, or microscopic Sloth, belongs to the order of
Arachnida, and is occasionally found in moss, stagnant ponds, etc.
I have only met with four specimens in all my investigations, and
they were all found in moss. SPALLANZANI described and figured
it (very badly), and M. DOYEEE has given a fuller description in
the Annaks des Sciences, 2d series, vols. xiv., xvii., and xviii.
68 STUDIES IN ANIMAL LIFE.
Never do these oval bodies become active crawling
Eotifers; never do they expand their wheels, and
set the oesophagus at work. No ; the Kotifer once
dried is dead, and dead forever.
But if, like a cautious experimenter, you vary
and control the experiment, and beside the glass
slide place a watch-glass containing Eotifers with
dirt or moss, you will find that the addition of wa-
ter to the contents of the watch-glass will often (not
always) revive the animals. What you can not ef-
fect on a glass slide without dirt, or with very little,
you easily effect in a watch-glass with dirt or moss ;
and if you give due attention you will find that in
each case the result depends upon the quantity of
the dirt. And this leads to a clear understanding
of the whole mystery ; this reconciles the conflict-
ing statements. The reason why Eotifers ever re-
vive is because they have not been dried they
have not lost by evaporation that small quantity
of water which forms an integral constituent of their
tissues; and it is the presence of dirt or moss which
prevents this complete evaporation. No one, I sup-
pose, believes that the Eotifer actually revives after
once being dead. If it has a power of remaining in
a state of suspended animation, like that of a frozen
frog, it can do so only on the condition that its or-
ganism is not destroyed; and destroyed it would
be if the water were removed from its tissues ; for,
strange as it may seem, water is not an accessory,
but a constituent element of every tissue; and this
STUDIES IN ANIMAL LIFE. 69
can not be replaced mechanically it can only be
replaced by vital processes. Every one who has
made microscopic preparations must be aware that
when once a tissue is desiccated, it is spoiled; it
will not recover its form and properties on the ap-
plication of water, because the water was not orig-
inally worked into the web by a mere process of
imbibition like water in a sponge but by a molec-
ular process of assimilation, like albumen in a mus-
cle. Therefore I say that desiccation is necessarily
.death, and the Eotifer which revives can not have
been desiccated. This being granted, we have only
to ask, "What prevents the Eotifer from becoming
completely dried ? Experiment shows that it is the
presence of dirt or moss which does this. The
whole marvel of the Eotifer's resuscitation, there-
fore, amounts to this : that if the water in which it
lives be evaporated, the animal passes into a state
of suspended animation, and remains so as long as
its own water is protected from evaporation.
I am aware that this is not easily to be reconciled
with M. Doyere's experiment, since the application
of a temperature so high as 300 Fahrenheit (nearly
a hundred degrees above boiling water) must, one
would imagine, have completely desiccated the ani-
mals, in spite of any amount of protecting dirt. It
is possible that M. Doyere may have mistaken that
previously-noticed swelling up of the bodies, on the
application of water, for a return to vital activity.
Tf not, I am at a loss to explain the contradiction ;
70 STUDIES IN ANIMAL LIFE.
for certainly in my experience a much more mod-
erate desiccation namely, that obtained by simple
evaporation over a mantelpiece or under a large
bell-glass always destroyed the animals if little or
no dirt were present.
The subject has recently been brought before the
French Academy of Sciences by M. Davaine, whose
experiments* lead him to the conclusion that those
Rotifers which habitually live in ponds will not re-
vive after desiccation, whereas those which live in
moss always do so. I believe the explanation to be
this : the Rotifers living in ponds are dried without
any protecting dirt or moss, and that is the reason
they do not revive.
After having satisfied myself on this point, I did
what perhaps would have saved me some trouble
if thought of before. I took down Spallanzani, and
read his account of his celebrated experiments. To
my surprise and satisfaction, it appeared that he
had accurately observed the same facts, but curious-
ly missed their real significance. Nothing can be
plainer than the following passage : " But there is
one condition indispensable to the resurrection of
wheel-animals : it is absolutely necessary that there
should be a certain quantity of sand; without it
they will not revive. One day I had two wheel-
animals traversing a drop of water about to evapo-
rate which contained very little sand. Three quar-
ters of an hour after evaporation they were dry and
* DAVAINE in Annales des Sciences Naturelles, 1858, x., p. 335.
STUDIES IN ANIMAL LIFE. 71
motionless. I moistened them with water to revive
them, but in vain, notwithstanding that they were
immersed in water many hours. Their members
swelled to thrice the original size, but they remain-
ed motionless. To ascertain whether the fact was
accidental, I spread a portion of sand, containing
animals, on a glass slide, and waited until it became
dry in order to wet it anew. The sand was care-
lessly scattered on the glass, so as to be a thin cov-
ering on some parts, and on others in a very small
quantity : here the animals did not revive ; but all
that were in those parts with abundance of sand re-
vived."* He further says that if sand be spread
out in considerable quantities in some places, much
less in others, and very little in the rest, on moist-
ening it the revived animals will be numerous in
the first, less numerous in the second, and none at
all in the third.
It is not a little remarkable that observations so
precise as these should have for many years passed
unregarded, and not led to the true explanation of
the mystery. Perhaps an inherent love of the mar-
velous made men greedily accept the idea of resus-
citation, and indisposed them to attempt an expla-
nation of it. Spallanzani's own attempt is certainly
not felicitous. He supposes that the dust prevents
the lacerating influence of the air from irritating and
injuring the animals. And this explanation is ac-
cepted by his translator.
* SPALLAKZAKI: Tracts on the Natural History of Animals and
Vegetable*: translated by Dalyell, ii., p. 129.
72 STUDIES IN ANIMAL LIFE.
[Since the foregoing remarks were in type, M.
Gavarret has published (Annales des Sciences Natu-
relles, 1859, xi., p. 315) the account of his experi-
ments on Eotifers and Tardigrades, in which he
found that after subjecting the moss to a desiccation
the most complete according to our present means,
the animals revived after twenty -four hours' immer-
sion of the moss in water. This result seems flatly
to contradict the result I arrived at, but only seems
to contradict it, for in my experiments the animals,
not the moss, were subjected to desiccation. Nev-
ertheless, I confess that my confidence was shaken
by experiments so precise, and performed by so dis-
tinguished an investigator, and I once more resumed
the experiments, feeling persuaded that the detec-
tion of the fallacy, wherever it might be, would be
well worth the trouble. The results of these con-
trolling experiments are all I can find room for
here : Whenever the animals were completely separated
from the dirt, they perished ; in two cases there was
a very little dirt a mere film, so to speak in the
watch-glass and glass cell, and this, slight as it was,
sufficed to protect two out of eight, and three out
of ten Eotifers, which revived on the second day ;
the others did not revive even on the third day aft-
er their immersion. In one instance, a thin cover-
ing-glass was placed over the water on the slide,
and the evaporation of the water seemed complete,
yet this glass cover sufficed to protect a Eotifer,
which revived in three hours.
STUDIES IN ANIMAL LIFE. 73
If we compare these results with those obtained
by M. Davaine, we can scarcely avoid the conclusion
that it is only when the desiccation of the Eotifers
is prevented by the presence of a small quantity of
moss or of dirt between the particles of which they
find shelter that they revive on the application of
water. And even in the severe experiments of M.
Doyere and M. Gavarret, some of the animals must
have been thus protected ; and I call particular at-
tention to the fact that, although some animals re-
vived, others always perished. But if the organiza-
tion of the Kotifer or Tardigrade is such that it can
withstand desiccation if it only needs the fresh ap-
plication of moisture to restore its activity all, or
almost all the animals experimented on ought to
revive ; and the fact that only some revive leads us
to suspect that these have not been desiccated a
suspicion which is warranted by direct experiments.
I believe, then, that the discrepancy amounts to
this : investigators who have desiccated the moss
containing animals find some of the animals revive
on the application of moisture, but those who desic-
cate the animals themselves will find no instances
of revival.]
The time spent on these Eotifers will not have
been misspent if it has taught us the necessity of
caution in all experimental inquiries. Although
experiment is valuable nay, indispensable as a
means of interrogating Nature, it is constantly lia-
ble to mislead us into the idea that we have rightly
D
74 STUDIES IN ANIMAL LIFE.
interrogated and rightly interpreted the replies;
and this danger arises from the complexity of the
cases with which we are dealing, and our proneness
to overlook or disregard some seemingly trifling
condition a trifle which may turn out of the ut-
most importance. The one reason why the study
of science is valuable as a means of culture, over
and above its own immediate objects, is that in it
the mind learns to submit to realities instead of
thrusting its figments in the place of realities en-
deavors to ascertain accurately what the order of
Nature w, and not what it ought to be or might be.
The one reason why, of all sciences, Biology is pre-
eminent as a means of culture, is, that, owing to the
great complexity of all the cases it investigates, it
familiarizes the mind with the necessity of attend-
ing to all the conditions, and it thus keeps the mind
alert. It cultivates caution, which, considering the
tendency there is in men to " anticipate Nature," is
a mental tonic of inestimable worth. I am far from
asserting that biologists are more accurate reasoners
than other men ; indeed, the mass of crude hypoth-
esis which passes unchallenged by them is against
such an idea. But, whether its advantage be used
or neglected, the truth nevertheless is, that Biology,
from the complexity of its problems, and the ne-
cessity of incessant verification of its details, offers
greater advantages for culture than any other branch
of science.
I have once or twice mentioned the words Mol-
s^pTupJ^
v v or TfeE if r
OF TfcE
STUDIES IN ANIMAL
lusk and Crustacean, to which the
with the language of Natural History wirl have at
tached but vague ideas ; and although I wanted to
explain these, and convey a distinct conception of
the general facts of classification, it would have
been too great an interruption. So I will here
make an opportunity, and finish the chapter with
an indication of the five types, or plans of struct-
ure, under one of which every animal is classed.
Without being versed in science, you discern at
once whether the book before you is mathematical,
physical, chemical, botanical, or physiological. In
like manner, without being versed in Natural His-
tory, you ought to know whether the animal be-
fore you belongs to the Yertebrata, Mollusca, Artic-
ulata, Kadiata, or Protozoa.
A glance at the contents of our glass vases will
yield us samples of each of these five divisions of
the animal kingdom. We begin with this Triton
(Fig. 17). It is a representative of the VERTEBRATE
division or sub-kingdom. You have merely to re-
member that it possesses a backbone and an inter-
nal skeleton, and you will at once recognize the
cardinal character which makes this Triton range
under the same general head as men, elephants,
whales, birds, reptiles, or fishes. All these, in spite
of their manifold differences, have this one charac-
ter in common they are all backboned ; they have
all an internal skeleton; they are all formed ac-
cording to one general tvpe. In all vertebrate ani-
76
STUDIES IN ANIMAL LIFE.
Fig. 17. MALE TBITON, OR WATEB-NEWT.
mals the skeleton is found to be identical in plan.
Every bone in the body of a triton has its corre-
sponding bone in the body of a man or of a mouse ;
and every bone preserves the same connection with
other bones, no matter how unlike may be the va-
rious limbs in which we detect its presence. Thus,
widely as the arm of a man differs from the fin of
a whale, or the wing of a bird, or the wing of a bat,
or the leg of a horse, the same number of bones,
and the same connections of the bones, are found in
each. A fin is one modified form of the typical
limb ; an arm is another ; a wing another. That
which is true of the limbs is also true of all the
other organs; and it is on this ground that we
speak of the vertebrate type. From fish to man
STUDIES IN ANIMAL LIFE. 77
one common plan of structure prevails, and the
presence of a backbone is the index by which to
recognize this plan.
The Triton has been wriggling grotesquely in
our grasp while we have made him our text, and,
now he is restored to his vase, plunges to the bot-
tom with great satisfaction at his escape. This wa-
ter-snail, crawling slowly up the side of the vase,
and cleaning it of the green growth of microscopic
plants, which he devours, shall be our representa-
tive of the second great division the MOLLUSCA.
I can not suggest any obvious character so distinct-
ive as a backbone by which the word mollusk may
at once call up an idea of the type which prevails
in the group. It won't do to say " shellfish," be-
cause many mollusks have no shells, and many ani-
mals which have shells are not mollusks. The
name was originally bestowed on account of the
softness of the animals. But they are not softer
than worms, and much less so than jellyfish. You
may know that snails and slugs, oysters and cuttle-
fish, are mollusks ; but if you want some one char-
acter by which the type may be remembered, you
must fix on the imperfect symmetry of the mol-
lusk's organs. I say imperfect symmetry, because it
is an error, though a common one, to speak of the
mollusk's body not being bilateral that is to say, of
its not being composed of two symmetrical halves.
A vertebrate animal may be divided lengthwise,
and each half will closely resemble the other ; the
78 STUDIES IN ANIMAL LIFE.
backbone forms, as it were, an axis, on either side
of which the organs are disposed ; but the mollusk
is said to have no such axis, no such symmetry. I
admit the absence of an axis, but I deny the total
absence of symmetry. Many of its organs are as
symmetrical as those of a vertebrate animal i. e.,
the eyes, the feelers, the jaws and the gills in Cut-
tlefish, Eolids, and Pteropods ; while, on the other
hand, several organs in the vertebrate animal are as
asymmetrical as any of those in the mollusk i. e.,
the liver, spleen, pancreas, stomach, and intestines.*
As regards bilateral structure, therefore, it is only
a question of degree. The vertebrate animal is not
entirely symmetrical, nor is the mollusk entirely
unsymmetrical. But there is a characteristic dis-
position of the nervous system peculiar to mol-
lusks : it neither forms an axis for the body, as it
does in the Yertebrata and Articulata, nor a centre,
as it does in the Eadiata, but is altogether irregular
and unsymmetrical. This will be intelligible from
the following diagram of the nervous systems of a
mollusk and an insect, with which that of a starfish
may be compared (Fig. 18). Here you perceive
how the nervous centres and the nerves which
* In some cases of monstrosity these organs are transposed, the
liver being on the left, and the pancreas on the right side. It was
in allusion to a case of this kind, then occupying the attention of
Paris, that MOLIERE made his Mededn malgre Lui describe the
heart as on the right side, the liver on the left ; on the mistake be-
ing noticed, he replies, " Oui, autrefois ; mais nous avons change
tout cela."
STUDIES IN ANIMAL LIFE.
79
Fig. 18. NERVOUS SYSTEM OP SEA-HABE (A) and CENTIPEDE (B).
Fig. 19. NERVOUS SYSTEM OF STARFISH.
80 STUDIES IN ANIMAL LIFE.
issue from them are irregularly disposed in the
mollusks, and symmetrically in the insect.
But the recognition of a mollusk will be easier
when you have learned to distinguish it from one
of the AETICULATA, forming the third great divi-
sion the third animal type. Of these, our vases
present numerous representatives prawns, beetles,
water-spiders, insect-larvae, entomostraca, and worms.
There is a very obvious character by which these
may be recognized : they have all bodies composed
of numerous segments, and their limbs are jointed,
and they have mostly an external skeleton from
which their limbs are developed. Sometimes the
segments of their bodies are numerous, as in the
centipede, lobster, etc. ; sometimes several segments
are fused together, as in the crab ; and sometimes,
as in worms, they are indicated by slight markings
or depressions of the skin, which give the appear-
ance of little rings, and hence the worms have been
named Annelida, or Annulata, or Annulosa. In these
last-named cases the segmental nature of the type is
detected in the fact that the worms grow, segment
by segment ; and also by the fact that- in most of
them each segment has its own nerves, heart, stom-
ach, etc. each segment is, in fact, a zooid.*
Just as we recognize a vertebrate by the presence
of a backbone and internal skeleton, we recognize
an articulate by its jointed body and external skele-
ton. In both, the nervous system forms the axis
* The term zooid was explained in our last chapter.
STUDIES IN ANIMAL LIFE. 81
of the body. The Mollusk, on the contrary, has no
skeleton, internal or external,* and its nervous sys-
tem does not form an axis. As a rule, both verte-
brates and articulates have limbs, although there
are exceptions in serpents, fishes, and worms. The
Mollusks have no limbs. Backboned, jointed, and
non-jointed, therefore, are the three leading charac-
teristics of the three types.
Let us now glance at the fourth division the
EADIATA, so called because of the disposition of the
organs round a centre, which is the mouth. Our
fresh- water vases afford us only one representative
of this type the Hydra, or fresh-water Polype,
whose capture was recorded in the last chapter. Is
it not strange that while all the Kadiata are aquatic,
not a single terrestrial representative having been
discovered, only one should be found in fresh wa-
ter? Think of the richness of the seas, with their
hosts of Polypes, Actiniae, Jellyfish, Starfishes, Sea-
urchins, Sea-pens (Pennatulce), Lily -stars (Comatu-
Ice), and Sea-cucumbers (Rolothurice), and then com-
pare the poverty of rivers, lakes, and ponds, re-
duced to their single representative, the Hydra.
The radiate structure may best be exhibited by the
diagram of the nervous system of the Starfishf on
page 79.
* In the cuttlefish there is the commencement of an internal
skeleton in the cartilage-plates protecting the brain.
+ It is right to add that there are serious doubts entertained re-
specting the claim of a starfish to the possession of a nervous sys-
D2
82 STUDIES IN ANIMAL LIFE.
Cuvier, to whom we owe this classification of the
animal kingdom into four great divisions, would
have been the first to recognize the chaotic con-
dition in which he left this last division, and would
have acquiesced in the separation of the PROTOZOA,
which has since been made. This fifth division in-
cludes many of the microscopic animals known as
Infusoria, and receives its name from the idea that
these simplest of all animals represent, as it were,
the beginnings of life.*
But Cuvier's arrangement is open to a more se-
rious objection. The state of science in his day
excused the imperfection of classing the Infusoria
and parasites under the Eadiata ; but it was owing, I
conceive, to an unphilosophical view of morphology
that he placed the mollusks next to the Yertebrata,
instead of placing the Articulata in that position.
He was secretly determined by the desire to show
that there are four very distinct types, or plans of
structure, which can not by any transitions be
brought under one law of development. Lamarck
and Geoffroy St. Hilaire maintained the idea of uni-
ty of composition throughout the animal kingdom :
in other words, that all the varieties of animal forms
were produced by successive modifications ; and
several of the German naturalists maintained that
the vertebrata in their embryonic stages passed
tern at all ; but the radiate structure is represented in the diagram,
as it also is, very clearly, in a Sea-anemone.
* Protozoa, from proton, first, and zoon, animal.
STUDIES IN ANIMAL LIFE. S3
through, forms which were permanent in the lower
animals. This idea Cuvier always opposed. He
held that the four types were altogether distinct;
and by his arrangement of them, their distinctness
certainly appears much greater than would be the
case on another arrangement. But, without dis-
cussing this question here, it is enough to point out
the fact of the enormous superiority in intelligence,
in sociality, and in complexity of animal functions
which insects and spiders exhibit when compared
with the highest of the mollusks, to justify the re-
moval of the mollusca, and the elevation of the ar-
ticulata to the second place in the animal hierarchy.
Nor is this all. If we divide animals into four
groups, these four naturally dispose themselves into
two larger groups: the first of these, comprising
Vertebrata and Articulata, is characterized by a
nervous axis and a skeleton ; the second, comprising
Mollusca and Eadiata, is characterized by the ab-
sence of both nervous axis and skeleton. It is ob-
vious that a bee much more closely resembles a
bird than any mollusk resembles any vertebrate.
If there are many and important differences be-
tween the vertebrate and articulate types, there are
also many and important resemblances ; if the nerv-
ous axis is above the viscera, and forms the dorsal
line of the vertebrate, whereas it is underneath the
viscera, and forms the ventral line in the articulate,
it is, nevertheless, in both, the axis of the body, and
in both it sends off nerves to supply symmetrical
84 STUDIES IN ANIMAL LIFE.
limbs ; in both it has similar functions. And while
the articulata thus approach in structure the verte-
brate type, the mollusca are not only removed from
that type by many diversities, but a number of them
have such affinities with the Eadiate type that it is
only in quite recent days that the whole class of
Polyzoa (or Bryozoa, as they are also called) has
been removed from the Eadiata, and ranged under
the Mollusca.
To quit this topic, and recur once more to the
five divisions, we have only the broad outlines of
the picture in Yertebrata, Mollusca, Articulata, Ea-
diata, and Protozoa ; but this is a good beginning,
and we can now proceed to the further subdivisions.
Each of these five sub-kingdoms is divided into
classes; these, again, into orders; these into fami-
lies; these into genera; these into species; and
these, finally, into varieties. Thus, suppose a dwarf
terrier is presented to us with a request that we
should indicate its various titles in the scheme of
classification : we begin by calling it a vertebrate ;
we proceed to assign its class as the mammalian ;
its order is obviously that of the carnivora ; its
family is that of the fox, wolf, jackal, etc., named
Canidce ; its genus is, of course, that of Canis ; its
species, terrier; its variety, dwarf terrier. Inas-
much as all these denominations are the expres-
sions of scientific research, and not at all arbitrary
or fanciful, they imply an immense amount of labor
and sagacity in their establishment ; and when we
{STUDIES IN ANIMAL LIFE. 85
remember that naturalists have thus classed upward
of half a million of distinct species, it becomes an
interesting inquiry, What has been -the guiding
principle of this successful labor? on what basis is
so large a superstructure raised ? This question we
shall answer in the next chapter.
STUDIES IN ANIMAL LIFE.
CHAPTER IV.
An extinct Animal recognized by its Tooth : how came this to be
possible ? The Task of Classification. Artificial and natural
Methods. Linnaeus, and his Baptism of the Animal Kingdom:
his Scheme of Classification. What is there underlying all
true Classification? The chief Groups. What is a Species?
Restatement of the Question respecting the Fixity or Variability
of Species. The two Hypotheses. Illustration drawn from the
Romance Languages. Caution to Disputants.
I WAS one day talking with Professor Owen in the
Hunterian Museum, when a gentleman approached
with a request to be informed respecting the nature
of a curious fossil which had been dug up by one
of his workmen. As he drew the fossil from a
small bag, and was about to hand it for examina-
tion, Owen quietly remarked, " That is the third
molar of the under jaw of an extinct species of rhi-
noceros." The astonishment of the gentleman at
this precise, and confident description of the fossil,
before even it had quitted his hands, was doubtless
very great. I know that mine was, until the reflec-
tion occurred that if some one, little acquainted with
editions, had drawn a volume from his pocket, de-
claring he had found it in an old chest, any biblio-
phile would have been able to say at a glance,
"That is an Elzevir;" or, "That is one of the
Tauchnitz classics, stereotyped at Leipzig." Owen
is as familiar with the aspect of the teeth of ani-
STUDIES IN ANIMAL LIFE. 87
raals, living and extinct, as a student is with the as-
pect of editions. Yet, before that knowledge could
have been acquired, before he could say thus confi-
dently that the tooth belonged to an extinct species
of rhinoceros, the united labors of thousands of dili-
gent inquirers must have been directed to the clas-
sification of animals. How could he know that the
rhinoceros was of that particular species rather than
another ? and what is meant by species ? To trace
the history of this confidence would be to tell the
long story of zoological investigation ; a story too
long for narration here, though we may pause a
while to consider its difficulties.
To make a classical catalogue of the books in the
British Museum would be a gigantic task ; but
imagine what that task would be if all the title-
pages and other external indications were destroy-
ed ! The first attempts would necessarily be of a
rough approximative kind, merely endeavoring to
make a sort of provisional order amid the chaos,
after which succeeding labors might introduce bet-
ter and better arrangements. The books might first
be grouped according to size ; but, having got them
together, it would soon be discovered that size was
no indication of their contents : quarto poems and
duodecimo histories, octavo grammars and folio
dictionaries, would immediately give warning that
some other arrangement was needed. Nor would
it be better to separate the books according to the
languages in which they were written. The pres-
88 STUDIO IN ANIMAL LIFE.
ence or absence of " illustrations" would furnish no
better guide, while the bindings would soon be
found to follow no rule. Indeed, one by one, all
the external characters would prove unsatisfactory,
and the laborers would finally have to decide upon
some internal characters. Having read enough of
each book to ascertain whether it was poetry or
prose and, if poetry, whether dramatic, epic, lyric,
or satiric; and if prose, whether history, philoso-
phy, theology, philology, science, fiction, or essay
a rough classification could be made ; but even then
there would be many difficulties, such as where to
place a work on the philosophy of history or the
history of science or theology under the guise of
science or essays on very different subjects, while
some works would defy classification.
Gigantic as this labor would be, it would be tri-
fling compared with the labor of classifying all the
animals now living (not to mention extinct species),
so that the place of any one might be securely and
rapidly determined ; yet the persistent zeal and sa-
gacity of zoologists have done for the animal king-
dom what has not yet been done for the library of
the Museum, although the titles of the books are
not absent. It has been done by patient reading of
the contents by anatomical investigation of the in-
ternal structure of animals. Except on a basis of
comparative anatomy, there could have been no
better a classification of animals than a classification
of books according to size, language, binding, etc.
STUDIES IN ANIMAL LIFE. 89
An unscientific Pliny might group animals accord-
ing to their habitat; but when it was known that
whales, though living in the water and swimming
like fishes, were in reality constructed like air-
breathing quadrupeds when it was known that
animals differing so widely as bees, birds, bats, and
flying squirrels, or as otters, seals, and cuttlefish,
lived together in the same element, it became ob-
vious that such a principle of arrangement could
lead to no practical result. Nor would it suffice to
class animals according to their modes of feeding,
since in all classes there are samples of each mode.
Equally unsatisfactory would be external form
the seal and the whale resembling fishes, the worm
resembling the eel, and the eel the serpent.
Two things were necessary : first, that the struc-
ture of various animals should be minutely studied
and described which is equivalent to reading the
books to be classified ; and, secondly, that some ar-
tificial method should be devised of so arranging the
immense mass of details as to enable them to be re-
membered, and also to enable fresh discoveries readi-
ly to find a place in the system. We may be per-
fectly familiar with the contents of a book, yet
wholly at a loss where to place it. If we have to
catalogue Hegel's Philosophy of History, for exam-
ple, it becomes a difficult question whether to place
it under the rubric of philosophy, or under that of
history. To decide this point, we must have some
system of classification.
90 STUDIES IN ANIMAL LIFE.
In the attempts to construct a system, naturalists
are commonly said to have followed two methods,
the artificial and the natural. The artificial method
seizes some one prominent characteristic, and groups
all the individuals together which agree in this one
respect. In Botany the artificial method classes
plants according to the organs of reproduction ; but
this has been found so very imperfect that it has
been abandoned, and the natural method has been
substituted, according to which the whole structure
of the plant determines its place. If flying were
taken as the artificial basis for the grouping of some
animals, we should find insects and birds, bats and
flying squirrels grouped together; but the natural
method, taking into consideration not one character,
but all the essential characters, finds that insects,
birds, and bats differ profoundly in their organiza-
tion : the insect has wings, but its wings are not
formed like those of the bird, nor are those of the
bird formed like those of the bat. The insect does
not breathe by lungs, like the bird and the bat ; it
has no internal skeleton, like the bird and the bat ;
and the bird, although it has many points in com-
mon with the bat, does not, like it, suckle its young;
and thus we may run over the characters of each
organization, and find that the three animals belong
to widely different groups.
It is to Linnaeus that we are indebted for the
most ingenious and comprehensive of the many
schemes invented for the cataloguing of animal
STUDIES IN ANIMAL LIFE. 91
forms, and modern attempts at classification are
only improvements on the plan he laid down. First
we may notice his admirable invention of the double
names. It had been the custom to designate plants
and animals according to some name common to a
large group, to which was added a description more
or less characteristic. An idea may be formed of
the necessity of a reform by conceiving what a la-
borious and uncertain task it would be if our friends
spoke to us of having seen a dog in the garden, and
on our asking what kind of a dog, instead of their
saying " a terrier, a bull-terrier, or a Skye-terrier,"
they were to attempt a description of the dog.
Something of this kind was the labor of under-
standing the nature of an animal from the vague
description of it given by naturalists. Linnaeus
rebaptized the whole animal kingdom upon one
intelligible principle. He continued to employ the
name common to each group, such as that of Felis
for the cats, which became the generic name ; and
in lieu of the description which was given of each
different kind to indicate that it was a lion, a tiger,
a leopard, or a domestic cat, he affixed a specific
name : thus the animal bearing the description of a
lion became Felis leo ; the tiger, Felis tigris ; the
leopard, Felis leopardus ; and our domestic friend,
Felis catus. These double names, as Yogt remarks,
are like the Christian- and sur-names by which we
distinguish the various members of one family ; and
instead of speaking of Tomkinson with the flabby
92 STUDIES IN ANIMAL LIFE.
face and Tomkinson with the square forehead, we
simply say John and William Tomkinson.
Linnaeus did more than this. He not only fixed
definite conceptions of species and genera, but in-
troduced those of orders and classes. Cuvier added
families to genera, and sub-kingdoms (embranclie-
menis) to classes. Thus a scheme was elaborated
by which the whole animal kingdom was arranged
in subordinate groups : the sub-kingdoms were di-
vided into classes, the classes into orders, the orders
into families, the families into genera, the genera
into species, and the species into varieties. The
guiding principle of anatomical resemblance determ-
ined each of these divisions. Those largest groups,
which resemble each other only in having what is
called the typical character in common, are brought
together under the first head. Thus all the groups
which agree in possessing a backbone and internal
skeleton, although they differ widely in form, struc-
ture, and habitat, do nevertheless resemble each
other more than they resemble the groups which
have no backbone. This great division having been
formed, it is seen to arrange itself in very obvious
minor divisions or classes the mammalia, birds,
reptiles, and fishes. All mammals resemble each
other more than they resemble birds ; all reptiles
resemble each other more than they resemble fishes
(in spite of the superficial resemblance between ser-
pents and eels or lampreys). Each class, again,
falls into the minor groups of orders, and on the
STUDIES IN ANIMAL LIFE. 93
same principles the monkeys being obviously dis-
tinguished from rodents, and the carnivora from
the ruminating animals ; and so of the rest. In each
order there are generally families, and the families
fall into genera, which differ from each other only
in fewer and less important characters. The genera
include groups which have still fewer differences,
and are called species; and these, again, include
groups which have only minute and unimportant
differences of color, size, and the like, and are call-
ed sub-species, or varieties.
"Whoever looks at the immensity of the animal
kingdom, and observes how intelligibly and system-
atically it is arranged in these various divisions,
will admit that, however imperfect, the scheme is a
magnificent product of human ingenuity and labor.
It is not an arbitrary arrangement, like the group-
ing of the stars in constellations; it expresses,
though obscurely, the real order of Nature. All
true classification should be to forms what laws are
to phenomena; the one reducing varieties to sys-
tematic order, as the other reduces phenomena to
their relation of sequence. Now if it be true that
the classification expresses the real order of Nature,
and not simply the order which we may find con-
venient, there will be something more than mere
resemblance indicated in the various groups; or,
rather let me say, this resemblance itself is the con-
sequence of some community in the things com-
pared, and will therefore be the mark of some deep-
94 STUDIES IN ANIMAL LIFE.
er cause. What is this cause ? Mr. Darwin holds
that "propinquity of descent the only known
cause of the similarity of organic beings is the
bond, hidden as it is by various degrees of modifi-
cation, which is partially revealed to us by our
classifications"* " that the characters which natu-
ralists consider as showing true affinity between
any two or more species are those which have been
inherited from a common parent, and in so far all
true classification is genealogical; that community
of descent is the hidden bond which naturalists
have been unconsciously seeking, and not pome
unknown plan of creation, or the enunciation of
general propositions, and the mere putting together
and separating objects more or less alike."f
Before proceeding to open the philosophical dis-
cussion which inevitably arises on the mention of
Mr. Darwin's book, I will here set down the chief
groups, according to Cuvier's classification, for the
benefit of the tyro in natural history, who will easi-
ly remember them, and will find the knowledge
constantly invoked.
There are four sub-kingdoms, or branches : 1.
Vertebrata; 2. Mollusca; 3. Articulata; 4. Eadi-
ata.
The YERTEBKATA consist of four classes : Mam-
malia, Birds, Eeptiles, and Fishes.
The MOLLUSCA consist of six classes : Cephalo-
poda (cuttlefish), Pteropoda, Gasteropoda (snails,
* DARWIN : Origin of Species, p. 414. f Ibid., p. 420.
STUDIES IN ANIMAL LIFE. 95
etc.), Acephala (oysters, etc.), Brachiopoda, and Cir-
rhopoda (barnacles). N.B. This last class is now
removed from the Mollusks and placed among the
Crustaceans.
The ARTICULATA are composed of four classes :
Annelids (worms), Crustacea (lobsters, crabs, etc.),
Arachnida (spiders), and Insecta.
The KADLATA embrace all the remaining forms;
but this group has been so altered since Cuvier's
time that I will not burden your memory just now
with an enumeration of the details.
The reader is now in a condition to appreciate
the general line of argument adopted in the discus-
sion of Mr. Darwin's book, which is at present ex-
citing very great attention, and which will, at any
rate, aid in general culture by opening to many
minds new tracts of thought. The benefit in this
direction is, however, considerably lessened by the
extreme vagueness which is commonly attached to
the word " species," as well as by the great want of
philosophic culture which impoverishes the major-
ity of our naturalists. I have heard or read few
arguments on this subject which have not impress-
ed me with the sense that the disputants really at-
tached no distinct ideas to many of the phrases they
were uttering. Yet it is obvious that we must first
settle what are the facts grouped together and indi-
cated by the word " species," before we can carry
on any discussion as to the origin of species. To
be battling about the fixity or variability of species,
96 STUDIES IN ANIMAL LIFE.
without having rigorously settled what species is,
can lead to no edifying result.
It is notorious that if you ask even a zoologist,
What is a species? you will always find that he
has only a very vague answer to give ; and if his
answer be precise, it will be the precision of error,
and will vanish into contradictions directly it is ex-
amined. The consequence of this is, that even the
ablest zoologists are constantly at variance as to
specific characters, and often can not agree whether
an animal shall be considered of a new species or
only a variety. There could be no such disagree-
ments if specific characters were definite if we
knew what species meant, once and for all. Ask a
chemist, What is a salt ? What an acid ? and his
reply will be definite and uniformly the same:
what he says all chemists will repeat. Not' so the
zoologist. Sometimes he will class two animals as
of different species, when they only differ in color,
in size, or in the numbers of tentacles, etc. ; at other
times he will class animals as belonging to the same
species, although they differ in size, color, shape, in-
stincts, habits, etc. The dog, for example, is said to
be one species with many varieties or races. But
contrast the pug-dog with the greyhound, the span-
iel with the mastiff, the bull-dog with the Newfound-
land, the setter with the terrier, the sheep-dog with
the pointer; note the striking differences in their
structure and their instincts, and you will find that
they differ as widely as some genera and as some
STUDIES IN ANIMAL LIFE. 97
species. If these varieties inhabited different coun-
tries if the pug were peculiar to Australia and the
mastiff to Spain there is not a naturalist but would
class them as of different species. The same re-
mark applies to pigeons and ducks, oxen and sheep.
The reason of this uncertainty is that the thing
species does not exist : the term expresses an ab-
straction, like virtue, or whiteness ; not a definite
concrete reality, which can be separated from other
things, and always be found the same. Nature pro-
duces individuals ; these individuals resemble each
other in varying degrees ; according to their resem-
blances we group them together as classes, orders,
genera, and species; but these terms only express
the relations of resemblance, they do not indicate the
existence of such things as classes, orders, genera, or
species.* There is a reality indicated by each term
that is to say, a real relation ; but there is no ob-
jective existence of which we could say, This is
variable, This is immutable. Precisely as there is
a real relation indicated by the term goodness, but
there is no goodness apart from the virtuous actions
and feelings which we group together under this
term. It is true that metaphysicians in past ages
angrily debated respecting the immutability of vir-
tue, and had no more suspicion of their absurdity
than moderns have who debate respecting the fixity
* CUVIER says, in so many words, that classes, orders, and gen-
era are abstractions, et rien de pareil n'existe dans la nature ; but
species is not an abstraction ! See Lettres a Pfaff, p. 179.
E
98 STUDIES IN ANIMAL LIFE.
of species. Yet no sooner do we understand that
species means a relation of resemblance between
animals, than the question of the fixity or varia-
bility of species resolves itself into this : Can there
be any variation in the resemblances of closely al-
lied animals? A question which would never be
asked.
No one has thought of raising the question of
the fixity of varieties, yet it is as legitimate as that
of the fixity of species ; and we might also argue
for the fixity of genera, orders, classes, the fixity of
all these being implied in the very terms ; since no
sooner does any departure from the type present
itself, than ~by that it is excluded from the category ;
no sooner does a white object become gray or yel-
low, than it is excluded from the class of white ob-
jects. Here, therefore, is a sense in which the phrase
" fixity of species" is indisputable ; but in this sense
the phrase has never been disputed. When zoolo-
gists have maintained that species are variable, they
have meant that animal forms are variable; and
these variations, gradually accumulating, result at
last in such differences as are called specific. Al-
though some zoologists, and speculators who were
not zoologists, have believed that the possibility of
variation is so great that one species may actually
be transmuted into another, i. e., that an ass may be
developed into a horse, yet most thinkers are now
agreed that such violent changes are impossible,
and that every new form becomes established only
STUDIES IN ANIMAL LIFE. 99
through the long and gradual accumulation of mi-
nute differences in divergent directions.
It is clear, from what has just been said, that the
many angry discussions respecting the fixity of spe-
cies, which, since the days of Lamarck, have dis-
turbed the amity of zoologists and speculative phi-
losophers, would have been considerably abbrevia-
ted-had men distinctly appreciated the equivoque
which rendered their arguments hazy. I am far
from implying that the battle was purely a verbal
one. I believe there was a real and important dis-
tinction in the doctrines of the two camps ; but it
seems to me that, had a clear understanding of the
fact that species was an abstract term been uniform-
ly present to their minds, they would have sooner
come to an agreement. Instead of the confusing
disputes as to whether one species could ever be-
come another species, the question would have been,
Are animal forms changeable? Can the descend-
ants of animals become so unlike their ancestors, in
certain peculiarities of structure or instinct, as to be
classed by naturalists as a different species ?
ISTo sooner is the question thus disengaged from
equivoque than its discussion becomes narrowed
within well-marked limits. That animal forms are
variable is disputed by no zoologist. The only
question which remains is this : To what extent are
animal forms variable? The answers given have
been two : one school declaring that the extent of
variability is limited to those trifling characteristics
100 STUDIES IN ANIMAL LIFE.
which mark the different varieties of each species ;
the other school declaring that the variability is in-
definite, and that all animal forms may have arisen
from successive modifications of a very few types,
or even of one type.
Now I would call your attention to one point in
this discussion which ought to be remembered when
antagonists are growing angry and bitter over the
subject; it is, that both these opinions are necessa-
rily hypothetical there can be nothing like posi-
tive proof adduced on either side. The utmost that
either hypothesis can claim is that it is more con-
sistent with general analogies, and better serves to
bring our knowledge of various points into har-
mony. Neither of them can claim to be a truth
which warrants dogmatic decision.
Of these two hypotheses, the first has the weight
and majority of authoritative adherents. It de-
clares that all the different kinds of bats, for exam-
ple, were distinct and independent creations, each
species being originally what we see it to be now,
and what it will continue to be as long as it ex-
ists : lions, panthers, pumas, leopards, tigers, jagu-
ars, ocelots, and domestic cats being so many origi-
nal stocks, and not so many divergent forms of one orig-
inal stock. The second hypothesis declares that all
these kinds of cats represent divergencies of the
original stock, precisely as the varieties of each kind
represent the divergencies of each species. It is
true that each species, when once formed, only ad-
STUDIES IN ANIMAL LIFE. 101
mits of limited variations ; any cause which should
push the variation beyond certain limits would de-
stroy the species, because by species is meant the
group of animals contained within those limits. Let
us suppose the original stock from which all these
kinds of cats have sprung to have become modified
into lions, leopards, and tigers in other words, that
the gradual accumulation of divergencies has re-
sulted in the whole family of cats existing under
these three forms. The lions will form a distinct
species; this species varies, and in the course of
long variation a new species, the puma, rises by the
side of it. The leopards also vary, and let us sup-
pose their variation at length assumes so marked a
form in the ocelot that we class it as a new spe-
cies. There is nothing in this hypothesis but what
is strictly consonant with analogies; it is only ex-
tending to species what we know to be the fact
with respect to varieties ; and these varieties which
we know to have been produced from" one and the
same species are often more widely separated from
each other than the lion is from the puma, or the
leopard from the ocelot. Mr. Darwin remarks that
" at least a score of pigeons might be chosen, which,
if shown to an ornithologist, and he were told that
they were wild birds, would certainly, I think, be
ranked by him as well-defined species. Moreover,
I do not believe that any ornithologist would place
the English carrier, the short-faced tumbler, the
runt, the barb, the pouter, and fantail in the same
102 STUDIES IN ANIMAL LIFE.
genus, more especially as in each, of these breeds
several truly -inherited sub-breeds or species, as he
might have called them, could be shown him."
The development of numerous specific forms,
widely distinguished from each other, out of one
common stock, is not a whit more improbable than
the development of numerous distinct languages
out of a common parent language, which modern
philologists have proved to be indubitably the case.
Indeed, there is a very remarkable analogy between
philology and zoology in this respect: just as the
comparative anatomist traces the existence of simi-
lar organs, and similar connections of these organs,
throughout the various animals classed under one
type, so does the comparative philologist detect the
family likeness in the various languages scattered
from China to the Basque Provinces, and from Cape
Comorin across the Caucasus to Lapland a like-
ness which assures him that the Teutonic, Celtic,
Wendic, Italic, Hellenic, Iranic, and Indie languages
are of common origin, and separated from the Ara-
bian, Aramean, and Hebrew languages, which have
another origin. Let us bring together a French-
man, a Spaniard, an Italian, a Portuguese, a Walla-
chian, and a Khastian, and we shall hear six very
different languages spoken, the speakers severally
unintelligible to each other, their languages differ-
ing so widely that one can not be regarded as the
modification of the other ; yet we know most posi-
tively that all these languages are offshoots from
STUDIES IN ANIMAL
the Latin, which was once a living language, but
which is now, so to speak, a fossil. The various
species of cats do not differ more than these six
languages differ, and yet the resemblances point in
each case to a common origin. Max Muller, in his
brilliant essay on Comparative Mythology* has said,
" If we knew nothing of the existence of Latin
if all historical documents previous to the fifteenth
century had been lost if tradition, even, was silent
as to the former existence of a Eoman empire, a
mere comparison of the six Eoman dialects would
enable us to say that at some time there must have
been a language from which all these modern dia-
lects derived their origin in common ; for without
this supposition it would be impossible to account
for the facts exhibited by these dialects. Let us
look at the auxiliary verb. "We find :
Italian. Wallachian. Rhsetian. Spanish. Portuguese. French.
I am sono sum sunt sunt soy sou suis.
Thou art sei es eis erea es es.
He is e < (este) ei es he est.
We are siamo suntemu essen somos somos sommes.
You are siete suntefi esses sois sois etes (estes).
They are sono sunt eon (sun) son eao sent.
It is clear, even from a short consideration of these
forms, first, that all are but varieties of one common
type ; secondly, that it is impossible to consider any
one of these six paradigms as the original from
which the others had been borrowed. To this we
may add, thirdly, that in none of the languages to
which these verbal forms belong do we find the
* See Oxford Essays, 1856.
104 STUDIES IN ANIMAL LIFE.
elements of which they could have been composed.
If we find such forms as f ai aime, we can explain
them by a mere reference to the radical means which
French has still at its command, and the same may
be said even of compounds like f aimer ai, i. e., je-
aimer-ai, I have to love, I shall love. But a change
from je suis to tu es is inexplicable by the light of
French grammar. These forms could not have
grown, so to speak, on French soil, but must have
been handed down as relics from a former period
must have existed in some language antecedent to
any of the Eoman dialects. Now, fortunately, in
this case, we are not left to a mere inference, but as
we possess the Latin verb, we can prove how, by
phonetic corruption and by mistaken analogies,
every one of the six paradigms is but a national
metamorphosis of the Latin original.
"Let us now look at another set of paradigms :
Sanscrit. j|j Zend. Doric. sla U ic> Latin. Gothic. Armen.
I am asmi esmi ahmi enm yesmo sum im em.
Thou art asi essi ahi e<ro-i yesi ea is es.
He is asti esti asti ka-ri yesto est ist e.
We (two) are . . 'svas esva yesva . . . eiju
You (two) are. . 'sthas esta stho? eo-rov yesta ... sijuts ...
They (two) are. 'stas (esti) sto? ea-rov yesta
We are 'smas esmi hmahi eoyxer yesmo sumus sijum emq.
You are 'stha este stha eo-re yeste estis sijup eq.
They are santi (esti) h^nti ev-ri somtS sunt sind en.
" From a careful consideration of these forms, we
ought to draw exactly the same conclusions ; first-
ly, that all are but varieties of one common type ;
secondly, that it is impossible to consider any of
them as the original from which the others have
STUDIES IN ANIMAL LIFE. 105
been borrowed ; and, thirdly, that here again none
of the languages in which these verbal forms occur
possess the elements of which they are composed."
All these languages resemble each other so close-
ly that they point to some more ancient language
which was to them what Latin was to the six Ko-
man languages ; and in the same way we are justi-
fied in supposing that all the classes of the verte-
brate animals point to the existence of some elder
type, now extinct, from which they were all de-
veloped.
I have thus stated what are the two hypotheses
on this question. There is only one more prelimi-
nary which it is needful to notice here, and that is,
to caution the reader against the tendency, unhap-
pily too common, of supposing that an adversary
holds opinions which are transparently absurd.
When we hear a hypothesis which is either novel
or unacceptable to us, we are apt to draw some very
ridiculous conclusion from it, and to assume that
this conclusion is seriously held by its upholders.
Thus the zoologists who maintain the variability
of species are sometimes asked if they believe a
goose was developed out of an oyster, or a rhinoce-
ros from a mouse ? the questioner apparently having
no misgiving as to the candor of his ridicule. There
are three modes of combating a doctrine. The first
is to point out its strongest positions, and then
show them to be erroneous or incomplete ; but this
plan is generally difficult, and sometimes impossi-
E2
106 STUDIES IN ANIMAL LIFE.
ble ; it is not, therefore, much in vogue. The sec-
ond is to render the doctrine ridiculous by pretend-
ing that it includes certain extravagant propositions
of which it is entirely innocent. The third is to
render the doctrine odious by forcing on it certain
conclusions which it would repudiate, but which are
declared to be " the inevitable consequences" of such
a doctrine. JSTow it is undoubtedly true that men
frequently maintain very absurd opinions; but it
is neither candid nor wise to assume that men who
otherwise are certainly not fools, hold opinions the
absurdity of which is transparent.
Let us not, therefore, tax the followers of La-
marck, Greoffroy St. Hilaire, or Mr. Darwin with ab-
surdities they have not advocated, but rather en-
deavor to see what solid argument they have for
the basis of their hypothesis.
STUDIES IN ANIMAL LIFE. 107
CHAPTER Y.
Talking in Beetles. Identity of Egyptian Animals with those now
existing : Does this prove Fixity of Species ? Examination of
the celebrated Argument of Species not having altered in four
thousand Years. Impossibility of distinguishing Species from
Varieties. The Affinities of Animals. New Facts proving the
Fertility of Hybrids. The Hare and the Rabbit contrasted.
Doubts respecting the Development Hypothesis. On Hypoth-
esis in Natural History. Pliny, and his Notion on the Forma-
tion of Pearls. Are Pearls owing to a Disease of the Oyster ?
Formation of the Shell; Origin of Pearls. How the Chinese
manufacture Pearls. *
A WITTY friend of mine expressed her sense of
the remoteness of the ancient Egyptians, and her
difficulty in sympathizing with them, by declar-
ing that " they talked in beetles, you know.' 1 ' 1 She
referred, of course, to the hieroglyphics in which
that curious people now speak to us from ancient
tombs. Whether these swarthy sages were elo-
quent and wise, or obscure and otherwise, in their
beetle-speech, it is certain that entomologists of our
day recognize their beetles as belonging to the same
species that are now gathered into collections. Such
as the Egyptians knew them, such we know them
now. Nay, the sacred cats found in those ancient
tombs are cats of the same kind as our own familiar
mousers ; they purred before Pharaoh as they purr
108 STUDIES IN ANIMAL LIFE.
on our hearth-rugs; and the descendants of the
very dogs which irreligiously worried those cats
are to this day worrying the descendants of those
sacred cats. The grains of wheat which the savans
found in the tombs were planted in the soil of
France, and grew into waving corn in no respect
distinguishable from the corn grown from the grain
of the previous year.
Have these familiar facts any important signifi-
cance? Are we entitled to draw any conclusion
from the testimony of paintings and sculptures, at
least four thousand years old, which show that sev-
eral of our well-known species of animals, and sev-
eral of the well-marked races of men, existed then,
and have not changetfsince then ? Nimrod hunted
with dogs and horses, which would be claimed as
ancestors by the dogs and horses at Melton Mow-
bray. The negroes who attended Semiramis and
Khamses are in every respect similar to the negroes
now toiling amid the sugar-canes of Alabama. If,
during four thousand years, species and races have
not changed, why should we suppose that they ever
will change ? Why should we not take our stand
on that testimony, and assert that species are un-
changeable ?
Such has been the argument of Cuvier and his
followers; an argument on which they have laid
great stress, and which they have further strength-
ened by a challenge to adversaries to produce one
single case where a transmutation of species has
STUDIES IN ANIMAL LIFE. 109
taken place: "Here we show you evidence that
species has persisted unaltered during four thousand
years, and you can not show us a single case of
species having changed you can not show us one
case of a wolf becoming a dog, an ass becoming a
horse, a hare becoming a rabbit. Yet you must
admit that if there were any inherent tendency
to change, four thousand years is a long enough
period for that tendency to display itself in ; and
we ought to see a very marked difference between
the species which lived under Semiramis and those
which are living under Victoria. Instead of this,
we see that there has been no change : the dog has
remained a dog, and the horse has remained a
horse ; every species retains its well-marked char-
acters."
No one will say that I have not done justice to
this argument. I have stated it as clearly and for-
cibly as possible, not with any design to captivate
your assent, but to make the answer complete.
This argument is the cheval de batailk of the Cuvier
school ; but, like many other argumentative war-
horses, it proves, on close inspection, to be spavined
and broken-winded. The first criticism we must
pass on it is that it implies the existence of species
as a thing which can be spoken of as fixed or varia-
ble ; whereas, as we saw in the last chapter, species
is an abstraction, like whiteness or strength. No one
supposes that there exists any whiteness apart from
white things, or strength apart from strong things ;
110 STUDIES IN ANIMAL LIFE.
yet the naturalists who maintain the fixity of spe-
cies constantly talk as if species existed independ-
ently of the individual animals. Instead of saying
that by the word species is indicated a certain group
of characters, and that whenever we meet with this
group we say, here is an animal of the same spe-
cies, they explicitly declare, or tacitly imply, that al-
though an individual dog may vary, there is some-
thing above all individuals the species and that
can not vary. As it is possible some readers may
protest that no respectable authority in modern
times ever held the opinion here imputed to a
school, I will quote the very explicit language of
one of Cuvier's disciples the last editor of Buffon
who, no later than 1856, could declare that " spe-
cies are the primitive forms of Nature. Individu-
als are nothing but the representatives the copies
of these forms: Les espbces sont les formes primitives
de la Nature. Les individus n'en sont que des repre-
sentations, des copies."* According to this very ex-
plicit but very extravagant statement, an individual
dog is nothing but a copy of the primitive form
the typical dog the idea of a dog, as Plato would
say ; and, of course, if this be true, it matters little
how widely individual dogs may vary, the type, or
species, of which it is the representative, remains
unaltered. Indeed, it is on this ground that many
physiologists explain the fact of hereditary trans-
mission: the individual may vary, it is said, but
* FLOURENS : Cours de Physioloyie Comparee, 1856, p. 9.
STUDIES IN ASTTMAL LIFE. Ill
the species is preserved ; and if a dog without its
fore paws has offspring, every one of which pos-
sesses the fore paws, the reason is, that Tidee de
Tespece se reproduit dans le fruit, et lui donne des or-
ganes qui manquaient au pbre ou d la mere* It is
not easy to understand how the idea of a species can
reproduce itself, and give the offspring of a dog the
organs which were wanting in the parents ; but to
those who believe that species exist independently
of individuals, and form the only real existences,
the conception may be easier.
I have too much respect for the reader to drag
him through a refutation of such philosophy as
this ; the statement of the opinion is enough. And
yet, unless some such opinion be maintained, the
doctrine of fixity of species is without a basis ; for
if it be said that the group of characters which con-
stitute the dog are incapable of change, and in this
sense species are fixed, we have to ask what evi-
dence there can be for such an assertion? since it
is notorious that individual dogs do show a change
in some of the characters of the group. We shall
be referred to the Egyptian tombs for evidence.
M. Flourens assures us that not only are these
tombs evidence that species have not changed in
four thousand years, but that no species has changed
aucune espece n'a change which is surely stepping
a long way beyond the precincts of the tombs !
It may be paradoxical, but it is strictly true, that
* BUKDACH : Physiologic, ii., 245.
112 STUDIES IN ANIMAL LIFE.
the fact of particular species having remained un-
altered during four thousand years does not add
the slightest weight to the evidence in favor of the
fixity of species. " What !" some may exclaim, " do
you pretend that four thousand years is not a period
long enough to prove the fixity of animal forms ?"
Yes ; I affirm that four thousand, or forty thousand,
prove no more than four. It is only by a fallacy
that the opposite opinion could gain acceptance.
You would not suppose that I had strengthened
my case if, instead of contenting myself with stating
reasons once, I repeated these same reasons during
forty successive pages ; you would remind me that
this iteration was not cumulation, and that no force
was given to my fortieth assertion which the first
wanted. Why, then, do you ask me to accept the
repetition of the same fact four thousand times over
as an increase of evidence? It is a familiar fact
that like produces like that dogs resemble dogs,
and do not resemble buffaloes ; this fact is, of course,
deepened in our conviction by the unvarying evi-
dence we see around us, and is guaranteed by the
philospphical axiom that like causes produce like
effects ; but when once such a conception is formed,
it can gain no fresh strength from any particular
instance. If we believe that crows are black, we
do not hold that belief more firmly when we are
shown that crows were black four thousand years
ago. In like manner, if it is an admitted fact that
individuals always reproduce individuals closely re-
STUDIES IN ANIMAL LIFE. 113
sembling themselves, it is not a whit more surpris-
ing that the dogs of Victoria should resemble the
dogs of Semiramis, than that they should resemble
their parents : the chain of four thousand years is
made up of many links, each link being a repetition
of the other. So long as a single pair of dogs re-
sembling each other unite, so long will there be
specimens of that species, simply because the chil-
dren inherit the characteristics of the parents. So
long as negroes marry with negroes, and Jews with
Jews, so long must there be a perpetuation of the
negro and Jewish types ; but the tenth generation
adds nothing to the evidence of the first, nor the
ten thousandth to the tenth.
I believe that this fallacy, which destroys the
whole value of the Cuvierian argument, has not
before been pointed out ; and even now you may
perhaps ask if the fixity of species is not proved by
the fact that like produces like? So far from this,
that it is only by the aid of such a fact in organic
nature that we can imagine new species to have
arisen ; in other words, those who believe in the
variability of species, and the introduction of new
forms by means of modification from the old, al-
ways invoke the law of hereditary transmission as
the means of establishing accidental variations.
Thus, let us suppose the Egyptian king to have
had one hundred dogs, all of them staghounds, and
no other form of dog to have existed at that time
in that country ; the dog species would be repre-
114 STUDIES IN ANIMAL LIFE.
sented by the staghound. These staghounds would
transmit to their offspring all their specific charac-
ters. But, as every one knows, however much dogs
may resemble each other, they always present in-
dividual differences in size, color, strength, intelli-
gence, etc. Now, if any one of these differences
should happen to become marked, and to increase
by the intermarriage of two dogs similarly distin-
guished by the marked peculiarity, this peculiarity
would in time become established by hereditary
transmission, and would form the starting-point of
a new race of dogs say the greyhound unless it
were obliterated by intermarriage with dogs of the
old type. In the former case, we should have two
races of dogs among the descendants of those fig-
ured on the Egyptian tombs; but as one of these
races would still preserve the original staghound
type, Cuvier would refer to it as a proof that spe-
cies had not varied. "We, on the other hand, should
point to the greyhound as proof that animal forms
are variable, and that a new form had arisen from
modification of the old.
An objection will at once be raised to this illus-
tration, to the effect that all zoologists admit the
possibility of new varieties or races being formed ;
but they deny that new species can be formed. It
is here that the equivoque of the word species pre-
vents a clear understanding of each other's argu-
ment. "Whiteness may justly be said to be unalter-
able; but white things may vary they may be-
STUDIES IN ANIMAL LIFE. 115
come gray or yellow. In like manner species must
be invariable, because species is a word indicating
a particular group of characters ; but animals may
vary in these characters: they may present some
of the characters less or more developed, and they
may even want some of them. Now, as there is
no absolute standard of what constitutes species,
what sub-species, and what varieties, it becomes
impossible to say whether any individual variation
in an animal form shall constitute a new variety or
a new species. "With regard to dogs, the differ-
ences between the various races are so numerous
and so marked as would suffice to constitute spe-
cies, and even genera, in other groups of animals.
"We must relinquish the idea of proving any
thing by the paintings and sculptures of the an-
cients. When we find an Egyptian plow closely
resembling the plow still in use in some places, we
may identify it as of the same " species" as our
own ; but this does not disprove the fact that steam-
plows, and plows of various construction, have
been since invented, all of them being modifica-
tions of the original type. Formerly, and for many
years, the stage-coach was our approved mode of
conveyance and it is still kept up in some dis-
tricts ; nevertheless, modifications of coachroad into
tramroad, and tramroad into railroad, have gradu-
ally resulted in a mode of conveyance utterly un-
like the stage-coach. It is the same with animals.
Let us never forget that species have no exist-
116 STUDIES IN ANIMAL LIFE.
ence. Only individuals exist, and these all vary
more or less from each other. When the modifica-
tions are slight, they have no name ; when they are
more marked, and are transmitted from one gener-
ation to another, they constitute particular races or
varieties ; when the differences are still more mark-
ed, they constitute sub-species ; but, as Mr. Darwin
says, " Certainly no clear line of demarkation has
yet been drawn between species and sub-species;
that is, the forms which in the opinion of some nat-
uralists come very near to, but do not quite arrive
at the rank of species ; or again, between sub-spe-
cies and well-marked varieties, or between lesser
varieties and individual differences. These differ-
ences blend into each other in an insensible series ;
and a series impresses the mind with the idea of an
actual passage." But the same process of diverg-
ence which establishes varieties out of individual
differences, and species out of varieties, also serves
to establish genera out of species, orders out of gen-
era, and classes out of orders. It is doubtless diffi-
cult to conceive by what process of modification
two animals of distinct genera, say a dog and a cat,
were produced from a common stock ; but organic
analogies in abundance render it easy of belief. If
we knew as much of zoology as we do of embryol-
ogy, in respect of the affinities of divergent forms,
it would be far less surprising that two different
genera should arise from a common stock, than that
all the various parts of the skeleton should arise
STUDIES IN ANIMAL LIFE. 117
from a common osseous element. "We know that
the jaws are identical with arms and legs both be-
ing divergent modifications of a common osseous
structure. We know that the arm of a man is
identical with the fin of a whale or the wing of a
bird. The differences here in form, size, and func-
tion are much greater than the differences which
establish orders and classes in the animal series.
Unless animal forms were modifications of some
common type, it would be difficult to explain their
remarkable affinities. As Mr. Darwin says, " It is
a truly wonderful fact the wonder of which we
are apt to overlook from familiarity that all ani-
mals and all plants throughout all time and space
should be related to each other in group subordi-
nate to group, in the manner which we every where
behold, namely, varieties of the same species most
closely related together, species of the same genus
less closely and unequally related together, forming
sections and sub-genera, species of distinct genera
much less closely related, and genera related in dif-
ferent degrees, forming sub-families, families, orders,
sub-classes, and classes. The several subordinate
groups in any class can not be ranked in a single
file, but seem rather to be clustered round points,
and these round other points, and so on in almost
endless circles. On the view that each species has
been independently created, I can see no explana-
tion of this great fact in the classification of all or-
ganic beings ; but, to the best of my judgment, it is
118 STUDIES IN ANIMAL LIFE.
explained through, inheritance, and the complex
action of natural selection entailing extinction and
divergence of character. The affinities of all the
beings of the same class have sometimes been rep-
resented by a great tree. I believe this simile
largely speaks the truth. The green and budding
twigs may represent existing species, and those pro-
duced during each former year may represent the
long succession of extinct species. At each period
of growth all the growing twigs have tried to branch
out on all sides, and to overtop and kill the sur-
rounding twigs and branches, in the same manner
as species and groups of species have tried to over-
master other species in the great struggle for life.
The limbs divided into great branches, and these
into lesser branches, were themselves once, when
the tree was small, budding twigs; and this con-
nection of the former and present buds by ramify-
ing branches may well represent the classification
of all extinct and living species in groups subordi-
nate to groups. Of the many twigs which flourish-
ed when the tree was a mere bush, only two or
three, now grown into great branches, yet survive
and bear all the other branches ; so with the spe-
cies which lived during long-past geological peri-
ods, very few now have living and modified de-
scendants. ... As buds give rise by growth to
fresh buds, and these, if vigorous, branch out and
overtop on all sides many a feebler branch, so by
generation, I believe, it has been with the great
STUDIES IN ANIMAL LIFE. 119
Tree of Life, which, fills with its dead and broken
branches the crust of the earth, and covers the sur-
face with its ever-branching and beautiful ramifica-
tions."*
It will not be expected that in these brief and
desultory remarks I should touch on all, or nearly
all, the important points in the discussion respect-
ing the fixity of species. Mr. Darwin's book is in
every body's hands, and my object has been to fa-
cilitate, if possible, the comprehension of his book,
and the adoption of a more philosophical hypothe-
sis, by pointing out the weakness of the chief argu-
ment on the other side. There is one more argu-
ment which may be noticed the more so as it is
constantly adduced with triumph by the one school,
and admitted as a difficulty by the other. Its force
is so great that it prevents many from accepting
the development hypothesis. It is the argument
founded on the alleged impossibility of hybrids
continuing the race. More than two or three gen-
erations of hybrids, it is said, can never be main-
tained; after that, the new form perishes, thus
clearly showing how Nature repudiates such amal-
gamations, and keeps her species jealously distinct
and invariable. This argument is held to be the
touchstone of the doctrine of species. I wish it
were so ; because, in that case, the question would
no longer be one of hypothesis, since we have now
the indubitable proof that some hybrids are fertile
unto the thirteenth generation and onward.
* DARWIN : Origin of Species, p. 128.
120 STUDIES IN ANIMAL LIFE.
A history of the various attempts which have
been made to prove and disprove the fertility of
hybrids would lead us beyond our limits ; the curi-
ous reader is referred to the works cited below.*
One decisive case alone shall be given here, and no
one will dispute that it is decisive.
The hare (lepus timidus) is assuredly of a distinct
species from the rabbit (lepus cuniculus). So dis-
tinct are these species, that any classification which
should range them as one would violate every ac-
cepted principle. The hare is solitary, the rabbit
gregarious; the hare lives on the surface of the
earth, the rabbit burrows under the surface ; the
hare makes her home among the bushes, the rabbit
makes a sort of nest for her young in her burrow
keeping them there till they are weaned ; the hare
has reddish-brown flesh, the rabbit white flesh ;
while the odor exhaled by each, and the flavor of
each, are unmistakably different. The hare has
many anatomical characters differing from those of
the rabbit, such as greater length and strength of
the hind legs, larger body, shorter intestine, thicker
skin, firmer hair, and different color. The hare
breeds only twice or thrice a year, and at each lit-
ter has only two or four; the rabbit will breed
eight times a year, and each time has four, six,
seven, and even eight young ones. Finally, the
* ISIDORE GEOFFROY ST. HILAIRE : Hist. Nat. Generate des
Regnes Organiques, 1860, iii., 207 sq. BROCA : Memoire sur IHy-
bridite, in BROWN-SEQUARD'S Journal de la Physiologic, 1859.
STUDIES IN ANIMAL ^, , , fir _
SITY
two are violent foes: the rabbits always destroy
the hares, and all sportsmen are aware that if the
rabbits be suffered to multiply on an estate, there
will be small chance of hares.
Nevertheless, between species so distinct as these,
a new hybrid race has been reared by M. Eouy, of
Angouleme, who each year sends to market upward
of a thousand of his Leporides, as he calls them.
His object was primarily commercial, not scientific.
His experiments, extending from 1847 to the pres-
ent time, have not only been of great commercial
value introducing a new and valuable breed
but have excited the attention of scientific men,
who are now availing themselves of his skill and ex-
perience to help them in the solution of minor prob-
lems. It is enough to note here that these hybrids
of the hare and the rabbit are fertile, not only with
either hares or rabbits, but with each other. Thir-
teen generations have already been enumerated,
and the last remains so vigorous that no cessation
whatever is to be anticipated.
In presence of this case (and others, though less
striking, might be named) there is but one alterna-
tive either we must declare that rabbits and hares
form one and the same species which is absurd
or we must admit that new types may be formed "by
the union of two existing races ; and, consequently,
that species are variable. If the doctrine of fixity
of species acknowledges the touchstone of hybrid-
ity, the fate of the doctrine is settled forever.
F
122 STUDIES IN ANIMAL LIFE.
Although I conceive the doctrine of fixity of
species to be altogether wrong, I can not say that
the arguments adduced in favor of the development
hypothesis rise higher than a high degree of proba-
bility, still very far from demonstration ; they will
leave even the most willing disciple beset with dif-
ficulties and doubts. When stated in general terms,
that hypothesis has a fascinating symmetry and
simplicity ; but no sooner do we apply it to partic-
ular cases, than a thick veil of mystery descends,
and our pathway becomes a mere blind groping to-
ward the light. There is nothing but what is per-
fectly conceivable, and in harmony with all analo-
gies, in the idea of all animal forms having arisen
from successive modifications of one original form,
but there are many things perfectly conceivable
which have nevertheless no existence ; there are
many explanations perfectly probable which are
not true ; and when we come to seek for the evi-
dence of the development hypothesis, that evidence
fails us. It may be true, but we can not say that it
is true. Ten years ago I espoused the hypothesis,
and believed that it must be the truth; but ten
years of study, instead of deepening, have loosened
that conviction : they have strengthened my oppo-
sition to the hypothesis of fixity of species, but
they have given greater force to the difficulties
which beset the development hypothesis, and have
made me feel that at present the requisite evidence
is wanting. I conclude with reminding the reader
STUDIES IN ANIMAL LIFE. 123
that the question of the origin of species is at pres-
ent incapable of a positive answer ; of the two hy-
potheses, that of development seems the more har-
monious with our knowledge; but it is no more
than an hypothesis, and will probably forever re-
main one. Now an hypothesis, although indispens-
able as a provisional mode of grouping together
facts, and giving them some sort of explanation, is,
after all, only a guess, and it may be absurdly wide
of the truth. In Natural History, as in all other
departments of speculative ingenuity, there have
been a goodly number of outrageously extravagant
hypotheses gravely propounded and credulously
accepted. Men prefer an absurd guess to a blank ;
they would rather have 'a false opinion than no
opinion ; and one of the last developments of phil-
osophic culture is the power of abstaining from
forming an opinion where the necessary data are
absent.
If you wish to see how easily hypotheses are
formed and accepted, you need only turn over the
history of any science. If you want a laugh at
credulity, read a chapter of Pliny's Natural History.
Pliny is a classic, and was for centuries an author-
ity ; but, looked at with impartial eyes, he appears
the veriest " old woman" that ever wrote in a beau-
tiful style. He was a mere bookworm, without a
particle of scientific insight. His was not an age
when men had much regard to evidence ; but to
him the suspicion never seems to have occurred
124 STUDIES IN ANIMAL LIFE.
that Gossip Eeport could be given to romancing,
or that travelers could "see strange things." No
fable is too monstrous for his credulity.
One of the pretty fables Pliny repeats is that
pearls are formed by drops of dew falling into the
gaping valves of the oyster. It never occurred to
him to ask whether oysters were ever exposed to
the dew? whether the drops could fall into their
valves ? whether oysters kept their valves open ex-
cept when under water ? or, finally, whether, if the
dew did fall in, it would remain a rounded drop ?
The drop of dew had a certain superficial resem-
blance to the pearl, and that was enough. Julian's
hypothesis was somewhat better : he supposed that
the pearls were produced by lightning flashing into
the open shells.
Turning from these ancient sages, you will ask
how pearls are formed ? And almost any ingenious
modern, not a zoologist, will tell you (and tell you
falsely) that the pearl is a disease of the oyster.
One is somewhat fatigued at the merciless frequen-
cy with which this notion has been dragged in, as
an illustration of genius issuing out of sorrow and
adversity, and it is time to stop that " damnable
iteration" by discrediting the notion. Know then
that if
" Most wretched men
Are cradled into poetry by wrong,
They learn in suffering what they teach in song"
it is not true that oysters secrete in suffering what
STUDIES IN ANIMAL LIFE. 125
women wear as necklaces. Disease would be the
very worst cradle for pearls. The idea of disease
originated in a fanciful supposition of pearls being
to the oyster and mussel what gall-stones and uri-
nary calculi are to higher and more suffering ani-
mals. Keaumur, to whom we owe so many good
observations and suggestive ideas, came near the
truth when, in 1717, he showed that the structure of
pearls was identical with the structure of the shells
in which they grow. He attributed their formation
to the morbid effusion of coagulating shell-material.
I presume you know that shells are formed by a
secretion from the mantle? The mantle is that
delicate semi-transparent membrane which you ob-
serve, on opening a mussel, lining the whole inte-
rior of the shells, and having at its free margins a
sort of fringe of delicate tentacles which are sensi-
tive and retractile. A microscopic examination of
these fringes shows them to be glandular in struc-
ture that is, they are secreting organs. The whole
mantle, indeed, is a secreting organ, and its secre-
tion is the shell-material: the fringes secrete the
coloring matters of the shell, and enlarge its circum-
ference ; the rest of the mantle secretes the nacre,
or mother of pearl, and increases the thickness of
the shell. Now it is obvious that the formation of
pearl nacre and of pearls depends on the healthy
condition of the mantle, not on its diseases. If the
mantle be injured, the nacre is not secreted at all,
or in less quantities.
126 STUDIES IN ANIMAL LIFE.
But, although pearls depend upon the healthy,
not the diseased activity of the mantle, it is clear
that there must be some unusual condition present
for their formation, since the secretion of nacre
does not spontaneously assume the form of pearls.
What is the unusual condition ? Naturalists are at
present divided into two camps, fighting vigorously
for victory. The one side maintains that the origin
of a pearl is this : an egg of the oyster has escaped
and strayed under the mantle, or the egg of a para-
site has been deposited there; this egg forms the
nucleus round which the nacre forms, and thus we
have the pearl. The other side maintains with
great positiveness that any thing will form a nucleus,
a grain of sand no less than the egg of a parasite.
'Tis a pretty quarrel, which we may leave them to
settle. Some aver that grains of sand are more nu-
merous than any thing else ; but Mobius says that
of forty -four sea pearls and fifteen fresh-water pearls
examined by him, not one contained a grain of sand ;
and Filippi, who has extensively investigated this
subject, denies that a grain of sand ever forms the
nucleus of a true pearl. Both Filippi and Kiichen-
meister* declare that a parasite gets into the mussel
or oyster, and its presence there stimulates an active
secretion of nacre.
There are pearls, according to Mobius, which
consist of three different systems of layers, like the
shells in which they are formed; with this differ-
* See their interesting essays in MULLER'S Archiv., 1856.
STUDIES IN ANIMAL LIFE. 127
ence, that these layers are reversed; in the shell the
nacre forms the innermost layer, in the pearl it
forms the outermost. Hence the qualities of the
pearl depend on the shell, and on the different pro-
portions of nacre and carbonate of lime.
Since we know how pearls are made, may it not
be expected that we should learn to make them ?
Ever since the days of Linnasus the hope has been
entertained, and it is now becoming every day more
likely to be realized. Imperfect pearls have been
made in abundance. The Chinese have long prac-
ticed the art. They simply remove the large fresh-
water mussel from the water, insert a foreign sub-
stance under the mantle, and in two or three years
(if I remember rightly) they take the mussels up
again, and find the pearls formed. In this way
they make little mother-of-pearl Josses, which are
sold for a penny each; and I remember seeing a
couple of large shells in the Anatomical Museum at
Munich, the whole length of which was occupied by
rows of little squab Josses, very comical to behold.
I was informed that a copper chain of these deities
had been inserted under the mollusk's mantle, and
this was the result.
128 STUDIES IN ANIMAL LIFE.
CHAPTER YI.
Every Organism a Colony. What is a Paradox ? An Organ is
an independent Individual and a dependent one. A Branch
of Coral. A Colony of Polypes. The Siphonophora. Uni-
versal Dependence. Youthful Aspirings. Our Interest in the
Youth of great Men. Genius and Labor. Cuvier's College
Life ; his Appearance in Youth ; his Arrival in Paris. Cuvier
and Geoffroy St.Hilaire. Causes of Cuvier's Success. One of
his early Ambitions. M. le Baron. Omnia vindt labor. Con-
clusion.
THAT an animal organism is made up of several
distinct organs, and these the more numerous in
proportion to the rank of the animal in the scale of
beings, is one of those familiar facts which have
their significance concealed from us by familiarity.
But it is only necessary to express this fact in lan-
guage slightly altered, and to say that an animal
organism is made up of several distinct individuals,
and our attention is at once arrested. Doubtless it
has a paradoxical air to say so ; but Natural His-
tory is full of paradoxes ; and you are aware that a
paradox is far from being necessarily an absurdity,
as some inaccurate writers would lead us to sup-
pose ; the word meaning simply " contrary to what
is thought" a meaning by no means equivalent to
" contrary to what is the fact." It is paradoxical
to call an animal an aggregate of individuals, but it
STUDIES IN ANIMAL LIFE. 129
is so because our thoughts are not very precise on
the subject of individuality one of the many ab-
stractions which remain extremely vague. To jus-
tify this application of the word individual to every
distinct organ would be difficult in ordinary speech,
but in philosophy there is ample warrant for it.
An organ, in the physiological sense, is an instru-
ment whereby certain functions are performed. In
the morphological sense, it arises in a differentiation,
or setting apart, of a particular portion of the body
for the performance of particular functions a group
of cells, instead of being an exact repetition of all
the other cells, takes on a difference, and becomes
distinguished from the rest as an organ.*
Combining these two meanings, we have the third
or philosophical sense of the word, which indicates
that every organ is an individual existence, depend-
ent more or less upon other organs for its mainte-
nance and activity, yet biologically distinct. I do
not mean that the heart will live independent of
the body at least not for long, although it does
continue to live and manifest its vital activity for
some time after the animal's death ; and, in the
cold-blooded animals, even after removal from the
body. Nor do I mean that the legs of an animal
will manifest vivacity after amputation, although
even the legs of a man are not dead for some time
after amputation; and the parts of some of the
lower animals are often vigorously independent.
* See on this point what was said in our first chapter, p. 22.
F2
130 STUDIES IN ANIMAL LIFE.
Thus I have had the long tentacles of a Terebella (a
marine worm) living and wriggling for a whole
week after amputation.* In speaking of the inde-
pendence of an organ, I must be understood to mean
a very dependent independence; because, strictly
speaking, absolute independence is nowhere to be
found ; and, in the case of an organ, it is of course
dependent on other organs for the securing, prepar-
ing, and distributing of its necessary nutriment.
The tentacles of my Terebella could find no nutri-
ment, and they perished from the want of it, as the
Terebella itself would have perished under like cir-
cumstances. The frog's heart now beating on our
table with such regular systole and diastole, as if it
were pumping the blood through the living animal,
gradually uses up all its force ; and since this force
is not replaced, the beatings gradually cease. A
current of electricity will awaken its activity for a
time, but at last every stimulus will fail to elicit a
response. The heart will then be dead, and decom-
position will begin.
Dependent, therefore, every organ must be on
some other organs. Let us see how it is also inde-
pendent ; and for this purpose we glance, as usual,
at the simpler forms of life to make the lesson easi-
er. Here is a branch of coral, which you know to
be in its living state a colony of polypes. Each of
these multitudinous polypes is an individual, and
each exactly resembles the others. But the whole
* Seaside Studies, 2d edition, p. 59 sq.
STUDIES IN ANIMAL LIFE.
131
colony has one nutritive fluid
in common. They are all
actively engaged in securing
food, and the labors of each
enrich all. It is animal so-
cialism of the purest kind
there are no rich and no poor,
neither are there any idlers.
Formerly the coral -branch
was regarded as one animal
an individual; and a tree
was and is commonly regard-
ed as one plant an individ-
ual. But no zoologist now
is unaware of the fact that
each polype on the branch is
a distinct individual, in spite
of its connections with the
rest; and philosophic bota-
nists are agreed that the tree is a colony of individ-
ual plants not one plant.
Let us pass from the coral to the stem of some
other polype, say a Campanularia. Above is the
representation of such a stem, of the natural size,
and beside it a tiny twig much magnified. You
observe the ordinary polype issuing from one of the
capsules, and expanding its coronal of tentacles in
the water. The food it secures will pass along the
digestive tract to each of the other capsules. Un-
der the microscope you may watch this oscillation
(mag .
132 STUDIES IN ANIMAL LIFE.
of the food. But your eye detects a noticeable dif-
ference between this polype in its capsule, and the
six semi-transparent masses in the second capsule ;
although the two capsules are obviously identical,
they are not the same ; a differentiation has taken
place. Perhaps you think that six polypes are
here crowding into one capsule ? Error ! If you
watch with patience, or if you are impatient yet
tolerably dexterous, you may press these six mass-
es out, and then will observe them swim away, so
many tiny jellyfish. Not polypes at all, but jelly-
fish, are in this capsule ; and these, in due time,
will produce polypes, like that one now waving
its tentacles.
Having made this observation, it will naturally
occur to you that the polype stem which bore such
different capsules as are represented by these two
may perhaps be called a colony, but it is a colony
of different individuals. While they have all one
skeleton in common, nutrition in common, and res-
piration in common, they have at least one differ-
entiation, or setting apart for a particular purpose,
and that is the reproductive capsule. This is an
individual as much as any of the others, but it is an
individual that does nothing for the general good ;
it takes upon itself the care of the race, and be-
comes an " organ" for the community ; the others
feed it, and it is absolved from the labor of nutri-
tion as much as the arm or the brain of a man are.
From this case, let us pass to the group of jelly-
STUDIES IN ANIMAL LIFE. 133
fish, called Siphonophora (siphon-bearers) by natu-
ralists, and we shall see this union of very differ-
ent individualities into one inseparable colony still
more strikingly exhibited : there are distinct indi-
viduals to feed the colony, individuals to float it
through the water, individuals to act as feelers, and
to keep certain parts distended with fluid, and final-
ly reproductive individuals. All these are identical
in origin, and differ only by slight differentiations.*
Here we have obviously an approach to the more
complex organism in which various distinct organs
perform the several functions, only no one calls the
organism a colony.
The individuals composing one of these Siphono-
phora are so manifestly analogous to organs, that
their individuality may perhaps be disputed, the
more so as they do not live separately. But the
gradations of separation are very fine. You would
never hesitate to call a bee or an ant an individual,
yet no bee or ant could exist if separated from its
colony. So great is the " physiological division of
labor" which has taken place among these insects,
that one can not get food, another can not feed it-
self, but it will fight for the community ; another
can not work, but it will breed for the community ;
another can not breed, but it will work. Each of
* Compare LEUCKART : Ueber den Polymorpliismus der Individ-
ven. GEGENBAUR : Grundzuge der Vergleichende Anatomie ; and
HUXLEY'S splendid monograph on the Oceanic Hydrozoa, published
by the Ray Society.
134 STUDIES IN ANIMAL LIFE.
these is little more than separated organs of the
great insect organism, as the heart, stomach, and
brain are united organs of the human organism.
Eemove one of these insects from the community,
and it will soon perish, for its life is bound up with
the whole.
And so it is every where ; the dependence is uni-
versal :
" Nothing in this world is single,
All things, by a law divine,
In one another's being mingle."
We are dependent on the air, the earth, the sun-
light, the flowers, the plants, the animals, and all
created things, directly or indirectly. Nor is the
moral dependence less than the physical. "We can
not isolate ourselves if we would. The thoughts
of others, the sympathies of others, the needs of
others these too make up our life ; without these
we should quickly perish.
It was a dream of the youth Cuvier that a His-
tory of Nature might be written which would sys-
tematically display this universal interdependence.
I know few parts of biography so interesting as
those which show us great men in their early aspir-
ings, when dreams of achievements vaster than
the world has seen fill their souls with energy to
achieve the something they do afterward achieve.
It is, unhappily, too often but the ambition of youth
we have to contemplate; and yet the knowledge
that after-life brought with it less of hope, less of
STUDIES IN ANIMAL LIFE. 135
devotion, and less of generous self-sacrifice, renders
these early days doubly interesting. Let the abate-
ment of high hopes come when it may, the exist-
ence of an aspiration is itself important. I have
been lately reading over again the letters of Cuvier
when an obscure youth, and they have given me
quite a new feeling with regard to him.
There is a good reason why novels always end
with the marriage of the hero and heroine ; our in-
terest is always more excited by the struggles than
by the results of victory. So long as the lovers
are unhappy or apart, and are eager to vanquish
obstacles, our sympathy is active; but no sooner
are they happy, than we begin to look elsewhere
for other stragglers on whom to bestow our inter-
est. It is the same with biography. We follow
the hero through the early years of struggle with
intense interest, and as long as he remains unsuc-
cessful, baffled by rivals or neglected by the world,
we stand by him and want him to succeed ; but the
day after he is recognized by the world our sym-
pathy begins to slacken.
It is this which gives Cuvier's Letters to Pfaff*
their charm. I confess that M. le Baron Cuvier,
administrator, politician, academician, professor, dic-
tator, has always had but a very tepid interest for
me, probably because his career early became a, con-
tinuous success, and Europe heaped rewards upon
* Lettres de Georges Cuvier a C. M. Pfaff, 1788-92. Traduites
de 1'Allemand, par Louis Marchant, 1858.
136 STUDIES IN ANIMAL LIFE.
him ; whereas his unsuccessful rival, Geoffrey St.
Hilaire, claims my sympathy to the close. If, how-
ever, M. le Baron is a somewhat dim figure in my
biographical gallery, it is far otherwise with the
youth Cuvier as seen in his letters ; and as at this
present moment there is nothing under our micro-
scope which can seduce us from the pleasant vol-
ume, suppose we let our " studies" take a biograph-
ical direction?
" Genius," says Carlyle, "means transcendent ca-
pacity for taking trouble, first of all." There are
many young gentlemen devoutly persuaded of their
own genius, and yet candidly avowing their im-
perfect capacity for taking trouble, who will vehe-
mently protest against this doctrine. Without dis-
cussing it here, let us say that, genius or no genius,
success of any value is only to be purchased by im-
mense labor : and in science, assuredly, no one will
expect success without first paying this price. In
Cuvier's history may be seen what " capacity for
taking trouble" was required before his success
could be achieved ; and this gives these Lettres d
Pfaff a moral as well as an interest.
It was in the Eittersaal of the Academia Carolina
of Stuttgardt that Pfaff, the once famous supporter
of Yolta, and in 1787 the fellow-student of Cuvier,
first became personally acquainted with him. Al-
though they had been three years together at the
same university, the classification of students there
adopted had prevented any personal acquaintance.
STUDIES IN ANIMAL LIFE. 137
Pupils were admitted at the age of nine, and com-
menced their studies with the classic languages.
Thence they passed to the philosophical class, and
from that they went to one of the four faculties
Law, Medicine, Administration, and Military Sci-
ence. Each faculty, of course, was kept distinct ;
and as Pfaff was studying philosophy at the time
Cuvier was occupied with the administrative sci-
ences, they never met, the more so as the dormito-
ries and hours of recreation were different. The
academy was organized on military principles. The
three hundred students were divided into six classes,
two of which comprised the nobles, and the other
four the bourgeoisie. Each of these classes had its
own dormitory, and was placed under the charge
of a captain, a lieutenant, and two inferior officers.
These six classes, in which the students were enter-
ed according to their age, size, and time of admis-
sion, were kept separate in their recreations as in
their studies. But those of the students who par-
ticularly distinguished themselves in the public ex-
aminations were raised to the rank of knights, and
had a dormitory to themselves, besides dining at
the same table with the young princes who were
then studying at the university. Pfaff and Cuvier
were raised to this dignity at the same time, and
here commenced their friendship.
What a charm there is in school friendships,
when youth is not less eager to communicate its
plans and hopes than to believe in the plans and
138 STUDIES IN ANIMAL LIFE.
hopes of others ; when studies are pursued in com-
mon, opinions frankly interchanged, and the supe-
riority of a friend is gladly acknowledged, even be-
coming a source of pride, instead of being, as in aft-
er years, a thorn in the side of friendship ! This
charm was felt by Cuvier and Pfaff, and a small
circle of fellow-students who particularly devoted
themselves to Natural History. They formed them-
selves into a society, of which Cuvier drew up the
statutes and became the president. They read mem-
oirs, and discussed discoveries with all the gravity
of elder societies, and even published, among them-
selves, a sort of Comptes Rendus. They made bo-
tanical, entomological, and geological excursions ;
and, still further to stimulate their zeal, Cuvier in-
stituted an Order of Merit, painting himself the me-
dallion: it represented a star, with the portrait of
Linnaeus in the centre, and between the rays vari-
ous treasures of the animal and vegetable world.
And do you think these boys were not proud when
their president awarded them this medal for some
happy observation of a new species, or some well-
considered essay on a scientific question ?
At this period Cuvier's outward appearance was
as unlike M. le Baron as the grub is unlike the
butterfly. Absorbed in his multifarious studies,
he was careless about disguising the want of ele-
gance in his aspect. His face was pale, very thin
and long, covered with freckles, and encircled by a
shock of red hair. His physiognomy was severe
STUDIES IN ANIMAL LIFE. 139
and melancholy. He never played at any of the
boys' games, and seemed as insensible of all that
was going on around him as a somnambulist. His
eye seemed turned inward; his thoughts moved
amid problems and abstractions. Nothing could
exceed the insatiable ardor of his intellect. Besides
his special administrative studies, he gave himself
to Botany, Zoology, Philosophy, Mathematics, and
the history of literature. No work was too volu-
minous or too heavy for him. He was reading all
day long, and a great part of the night. "I re-
member well," says Pfaff, " how he used to sit by
my bedside going regularly through Bayle's Dic-
tionary. Falling asleep over my own book, I used
to awake after an hour or two, and find him mo-
tionless as a statue, bent over Bayle." It was dur-
ing these years that he laid the basis of that exten-
sive erudition which distinguished his works in
after life, and which is truly remarkable when we
reflect that Cuvier was not in the least a bookworm,
but was one of the most active workers, drawing his
knowledge of details from direct inspection when-
ever it was possible, and not from the reports of
others. It was here, also, that he preluded to his
success as a professor, astonishing his friends and
colleagues by the clearness of his exposition, which
he rendered still more striking by his wonderful
mastery with the pencil. One may safely say that
there are few talents which are not available in
Natural History ; a talent for drawing is pre-emi-
140 STUDIES IN ANIMAL LIFE.
nently useful, since it not only enables a man to
preserve observations of fugitive appearances, but
sharpens his faculty of observation by the exercise
it gives. Cuvier's facile pencil was always em-
ployed: if he had nothing to draw for his own
memoirs or those of his colleagues, he amused him-
self with drawing insects as presents to the young
ladies of his acquaintance an entomologist's gal-
lantry, which never became more sentimental.
In 1788, that is, in his nineteenth year, Cuvier
quitted Stuttgardt, and became tutor in a noble-
man's family in Normandy, where he remained till
1795, when he was discovered by the Abbe Tessier,
who wrote to Parmentier, " I have just found a
pearl in the dunghill of Normandy :" to Jussieu. he
wrote, " Kemember it was I who gave Delambre to
the academy ; in another department this also will
be a Delambre." Geoffroy St. Hilaire, already pro-
fessor at the Jardin des Plantes, though younger
than Cuvier, was shown some of Cuvier's manu-
scripts, which filled him with such enthusiasm that
he wrote to him, " Come and fill the place of Lin-
naeus here ; come and be another legislator of nat-
ural history." Cuvier came, and Geoffroy stood
aside to let his great rival be seen.
Goethe, as I have elsewhere remarked, has no-
ticed the curious coincidence of the three great zo-
ologists successively opening to their rivals the path
to distinction : Buffon called Daubenton to aid him ;
Daubenton called Geoffroy; and Geoffroy called
STUDIES IN ANIMAL LIFE. 141
Cuvier. Goethe further notices that there was the
same radical opposition in the 'tendencies of Buffon
and Daubenton as in those of Geoffroy and Cuvier
the opposition of the synthetical and the analyt-
ical mind. Yet this opposition did not prevent
mutual esteem and lasting regard. Geoffroy and
Cuvier were both young, and had in common am-
bition, love of science, and the freshness of unform-
ed convictions. For, alas ! it is unhappily too true,
that just as the free communicativeness of youth
gives place to the jealous reserve of manhood, and
the youth who would only be too pleased to tell all
his thoughts and all his discoveries to a companion
would in after years let his dearest friend first see a
discovery in an official publication, so likewise, in
the early days of immature speculation, before con-
victions have crystallized enough to present their
sharp angles of opposition, friends may discuss and
interchange ideas without temper. Geoffroy and
Cuvier knew no jealousy then. In after years it
was otherwise.
Geoffroy had a position he shared it with his
friend; he had books and collections they were
open to his rival ; he had a lodging in the museum
it was shared between them. Daubenton, older
and more worldly wise, warned Geoffroy against this
zeal in fostering a formidable rival, and one day
placed before him a copy of Lafontaine open at the
fable of The Bitch and her Neighbor. But Geoffroy
was not to be daunted, and probably felt himself
142 STUDIES IN ANIMAL LIFE.
strong enough to hold his own. And so the two
happy, active youths pursued their studies together,
wrote memoirs conjointly, discussed, dissected, spec-
ulated together, and " never sat down to breakfast
without having made a fresh discovery," as Cuvier
said truly enough, for to them every step taken was
a discovery.
Cuvier became almost immediately famous on his
arrival at Paris, and his career henceforward was
one uninterrupted success. Those who wish to
gain some insight into the causes of this success
should read the letters to Pfaff, which indicate the
passionate patience of his studies during the years
1788-1795, passed in obscurity on the Norman
coast. Every animal he can lay hands on is dis-
sected with the greatest care, and drawings are
made of every detail of interest. Every work that
is published of any note in his way is read, ana-
lyzed, and commented on. Lavoisier's new system
of chemistry finds in him an ardent disciple. Kiel-
meyer's lectures open new vistas to him. The mar-
vels of marine life, in those days so little thought
of, he studies with persevering minuteness and with
admirable success. He dissects the cuttlefish, and
makes his drawings of it with its own ink. He
notes minute characters with the patience of a spe-
cies-monger, whose sole ambition is to affix his
name to some trifling variation of a common form,
yet with this minuteness of detail he unites the large-
ness of view necessary to a comparative anatomist.
STUDIES IN AN
" Your reflections on the diffe
mals and plants," he writes, t; in the passage to
which I previously referred, will be the more agree-
able to me, because I am at present working out a
new plan of a general natural history. I think we
ought carefully to seek out the relation of all exist-
ences with the rest of nature, and, above all, to show
their part in the economy of the great All. In this
work I should desire that the investigator should
start from the simplest things, such as air and wa-
ter, and after having spoken of their influence on
the whole, he should pass gradually to the com-
pound minerals, from these to plants, and so on;
and that at each stage he should ascertain the exact
degree of composition, or, which is the same thing,
the number of properties it presents over and above
those of the preceding stage, the necessary effects
of these properties, and their usefulness in creation.
Such a work is yet to be executed. The two works
of Aristotle, De Historia Animalium, and De Parti-
lus Animalium, which I admire more each time that
I read them, contain a part of what I desire, name-
ly, the comparison of species, and many of the gen-
eral results. It is, indeed, the first scientific essay
at a natural history. For this reason it is necessa-
rily incomplete, contains many inaccuracies, and is
too far removed from a knowledge of physical laws."
He passes on from Aristotle to Pliny, Theophrastus,
Dioscorides, Aldovrandus, Gesner, Gaspar Bauhin,
144 STUDIES IN ANIMAL LIFE.
and Kay, rapidly sketching the history of natural
history as a science, and concluding with this criti-
cism on these attempts at a nomenclature which
neglected real science: " These are the dictionaries
of natural history ; but when will the language be
spoken ?"
No one who reads these letters attentively will
be surprised at the young Cuvier's taking eminent
rank among the men of science in France ; and
Pfaff, on arriving in Paris six years afterward,
found his old fellow-student had become " a per-
sonage." The change in Cuvier's appearance was
very striking. He was then at his maturity, and
might pass for a handsome man. His shock of red
hair was now cut and trimmed in Parisian style;
his countenance beamed with health and satisfac-
tion ; his expression was lively and engaging ; and,
although the slight tinge of melancholy which was
natural to him had not wholly disappeared, yet the
fire and vivacity of his genius overcame it. His
dress was that of the fashion of the day, not with-
out a little affectation. Yet his life was simple,
and wholly devoted to science. He had a lodg-
ing in the Jardin des Plantes, and was waited on
by an old housekeeper, like any other simple pro-
fessor.
On Pfaff 's subsequent visit things were changed.
Instead of the old housekeeper, the door was open-
ed by a lackey in grand livery. Instead of asking
STUDIES IN ANIMAL LIFE. 145
for " Citizen Cuvier," lie inquired for Monsieur Cu-
vier ; whereupon the lackey politely asked whether
he wished to see M. le Baron Cuvier, or M. Frede-
ric, his brother ? "I soon found where I was,''
continues Pfaff. " It was the baron, separated from
me by that immense interval of thirty years, and by
those high dignities which an empire offers to the
ambition of men." He found the baron almost
exclusively interested in politics, and scarcely giv-
ing a thought to science. The " preparations" and
"injections" which Pfaff had brought with him
from Germany as a present to Cuvier were scarce-
ly looked at, and were set aside with an indifferent
" that's good," and " very fine ;" much to Pfaff's
distress, who doubtless thought the fate of the Mar-
tignac ministry an extremely small subject of in-
terest compared with these injections of the lym-
phatics.
But it is not my purpose to paint Cuvier in his
later years. It is to the studies of his youth that I
would call your attention, to read there, once again,
the important lesson that nothing of any solid value
can be achieved without entire devotion. Nothing
is earned without sweat of the brow. Even the
artist must labor intensely. What is called "in-
spiration" will create no works, but only irradiate
works with felicitous flashes ; and even inspiration
mostly comes in moments of exaltation produced
by intense work of the mind. In science, incessant
146 STUDIES IN ANIMAL LIFE.
and enlightened labor is necessary, even to the
smallest success. Labor is not all ; but without it
genius is nothing.
With this homily, dear reader, may be closed our
FIRST SERIES of Studies ; to be resumed hereafter,
let me hope, with as much willingness on your part
as desire to interest you on mine.
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