On our knowledge of the causes of the phenomena of organic nature

- Ne ID ee ee “
i ae ag EEE POLE PEE ORES PRERDLE RD 2REIOEIEIS enna
gS atl aa a EIN POL IO I I, LM Bn, in IN ti i eB a ~ oo =

a aed nee Ec ee nie dictated edhe cde ee Uti alien adh ek aie ae ee te" . ade * ca x”
o Soseewabenuue ES ESS SA EAL ha ee RE

PO OF ee oo a ee ie xe lee oli ee en - Pete Rage oP a “peat ae a ra
— | tatiana : ee Pe CR Se Roa ig ang Me ttinn Sag Bh
FOE AP aide i, > Ot cate Cee A ye ge Bee 6 EN ee, TNT phe en tg Rye 2D ye ee fen ety Op
a hatha Ayal CO ee I > Sah PM ee ae ey Pec, Tey Sy a my, ve

SP Adee tyne IR Pest Soe T+ Ab OE dieting ete ae ieee ee ee ee
(0 act ot RP alin, Pit Rr ES Sr ay PE AP np OP EP LRN i MO A Nae este fe op wn, ae eed wn
o- ee en ca Fe = gS ee A) POE RE eg NE Pg Re a al Mer tae ot sien” 4 Rap J et Z le

okt ‘ . omeaes SE ae en Lo ee a Am = Rm te IN a, yin a a ae

; a pre eng < 2 a Sr NNN i a i a” Ni tad de ae tagi AD mt al our ye hed
ON en! eR Fae he tk a a ce Rete teeta gh oh, pak nn ne oe eee ee ee re er OE Eaten te se
PR A SORIA EE DGS Piaf iy ing tatieges spraspatin apg oat tinge a ee gry, “RE Mge es MT sr vi
Mapes “Egor # | ange gine glia we de kt ee Me EES EE te OO el Mae a ee ee ae ee ee She Fete hae Te Fig ie ww
ie ar . Ut hatin nme ge ke nee A NI Way IN CT MER Prt oat oeinash am dhe ethos ak one ee we >
hod Rr Re, eee PELE DRE GONE LDAP Papa ne at st TiN LE a i: I a, Rag i Na Rl Ty ty Oe Rn Pag Eg Pua » 4
, hy ti" ISSIR Iai Oe Pie gm RR Be Rt Nee te tty tee Rye ee eg MY A Ce ae Cay AE PN ‘" »
PV ee PRL LLL LOL AED OLIGR IORI reef ty ya PN IS CIT te Cg MP ag it Ti Me Io Ree Sg Re Rags Mag Pa a! ey +
Ad die OT EELS BILBO Ege lO Ie a Re i a eee a
ae i at ae
;

nN
3

a

s
APIECE P OPER ESR ULES LESS LELLOL OUI CES .
4¢
§
¢
)
2
;
4
s
ee
2
5
i
<?
e?
rf
i
i
s§
if
+48

%*
2

{
i
4
i

*
§
t

&
+” Neate nd 4

iyt
ahd

PHI NTAs se TyS
pes 59d ak 4
TPO 2s 4
aN

tan

te
. 7 PR Mf Ry PR GR Ag IO ce Mig iD bl rap Pane STP Re Pag age ge eet a el
' — PEL ALAA ALLA LRLIAL LAL ILD, PIR veneer mr tn OPER gl Rael yO ig gg yt nag ang,
my * . PERLE LE LCL LOSE LIN AES IRL MS AO foe Sh ee PR SLING tO Gf Cog Me ENON, a Pe ee ed = >
(Be ee pnp EO ALAA APRA AS BALM OIA IOI I OAM RN ay gt i pt Darl, tm AO ye le Be: = € 62 4
= eet - SPRL EA LO Le ca LI LM Pe SMI Ie ag tailing i: ;
Ou Z . . oo ~~ A é
a 8 PLA Cag a Ry I ey OS AE py pan ef Pan ge 7 P
a = ect é
Te ¥ yim we -
(led “ _
me Soph age .
Po Caer ag ae 2
wey we °
~ Oj ~— “
& ge ’ =
se fom... = ~
—- > *
= =z os .
> Se ae .
Pe ge ee * ,
~—e ee =
~ a - "s a .
fe age “te : Pg Bh ete. c ~ ra rae a
Medlin. 3 .* - Nae ig Nag a TEL Gee aad ge agin na ai al
» &® ~ PRL LLIN LP AP CL PRP my Pre P en ht, lathe satis tlie cnet afin ee ideas chek a Penal Rig Lat ae" nal ng Nig Anping sing Ee! es
ee SOO AEE AMR RR ee te, ee Leh ee on ys so me " a's
~ heat OF pe SI EO A NR ES Bo NM eS FBT EGNOS REIS LE NESE NE EAS RUB TEI AE IM lg IM aE nT tak PBI NPT ISSN AS eS Rite aD
Bad paeeee . pat ~— a 9 — on as ee ba al ; lay scuahet eines Oatehae
< ose “ee te poe LEAP E EI AIC, ENE AEB a RII EDR, BIE Pa, EE en tee cage, See 5 ’
fe Se a gm Fe omy ~oNe tge PO ee ge Phar mts ee Pa ey oO ore oy 750% > e. &
ee Se’ eS oe = * ef * ae Sm? oF yA a ae aoe * es a
MK ~< oh as xn. - de ee ~ Naan, “aml ee cn one a oe e ww 7 wo - “ . .
~~ = hs + er PE Bly ge Oe a Nees Oh im foarte a igs a eet et, Ye 4 we eon PR ~~ < “
Sw wet AR Nhe se DOA AAG eM ee oe wre lstin Cyt nt eR Bo way = Mtn? nly i.
oe me ee ~ » 7 - ~ —™ - 7 - “— . a whe Pravin ” me
6 LOA Le i PLE EE CELLS LOE I GICLEE, LN, Re eT eG IS PML I SE A eee ee —sew
sh = im _ % al i may Oe eee ~ - Seas) oad — ate te
PTET A EEE i GS a oe RE SE te hh ee Ne I ee _S Ne DR as BI, NE" Mee, ma, Me Ree fon ee ae ety
. aN tng al Tae Ni it LG LE a le Al Mig ie min yt
~ wwe wn © © - or A

wee Ke - 7 = aa pert ay 2 ey Te.
Nl a Oy sn gy, naa ty CE, 4M, in ain ai i el ee ee

- 4
© it" Ss ae
-e .

—%

\7 1%

\ Bye?
35 “OE — ZOO

PROFESSOR HUXLEY’S LECTURES

TO

WORKING MEN.

ON OUR KNOWLEDGE

OF THE

CAUSES OF THE PHENOMENA

OF

ORGANIC NATURE.

BY

PROFESSOR HUXLEY, F.R.S.

LONDON:
ROBERT HARDWICKE, 192, PICCADILLY.
1862.

ae

NOTICE.

—

Tue Publisher of these interesting Lectures, having
made an arrangement for their publication with
Mr. J. A. Mays, the Reporter, begs to append the fol-
lowing note from Professor Huxley :—

“Mr. J. Aldous Mays, who is taking shorthand
notes of my ‘ Lectures to Working Men,’ has asked
ine to allow him, on his own account, to print those
Notes for the use of my audience. I willingly accede
to this request, on the understanding that a notice is
prefixed to the effect that I have no leisure to revise
the Lectures, or to make alterations in them, beyond
the correction of any important error in a matter

of fact.”

Lied, hin e

y

ml

eery tee: oho

CONTENTS.

eh atlas
NO. PAGE
I. The Present Condition of Organic Nature oe ine et
II. The Past Condition of Organic Nature ... a oe eo

II. The Method by which the Causes of the Present and Past
Conditions of Organic Nature are to be Discovered —
The Origination of Living Beings .., Ae dea 1

IV. The Perpetuation of Living Beings, Hereditary Trans-
mission aud Variation .., ss ae Pe See

V. The Conditions of Existence as affecting the Perpetua-
tion of Living Beings ... oe io Be a se LOR

VI. A Critical Examination of the Position of Mr. Darwin’s
Work, “On the Origin of Species,” in relation to the
complete Theory of the Causes of the Phenomena of
Organic Nature... ad 55g rr dig ... 133

vi part

i AEN a
"ies *

AY ain' ese.

feens

ieee pene
a Heth vhs

LECTURE IT.

THE PRESENT CONDITION OF ORGANIC
NATURE.

WueEn it was my duty to consider what subject I
would select for the six lectures which I shall now have
the pleasure of delivering to you, it occurred to me
that I could not do better than endeavour to put before
you in a true light, or in what I might perhaps with
more modesty call, that which I conceive myself to be
the true light, the position of a book which has been
more praised and more abused, perhaps, than any
book which has appeared for some years;—I mean
Mr. Darwin’s work on the “ Origin of Species.” That
work, I doubt not, many of you have read; for I know
the inquiring spirit which is rife among you. At any
‘rate, all of you will have heard of it,—some by one kind
of report and some by another kind of report; the
attention of all and the curiosity of all have been pro-
bably more or less excited on the subject of that work.
All I can do, and all I shall attempt to do, is to put
before you that kind of judgment which has been
formed by a man, who, of course, is liable to judge
erroneously ; but at any rate, of one whose business and

~

profession it is to form judgments upon questions of
this nature.

6 THE PRESENT CONDITION

And here, as it will always happen when dealing with
an extensive subject, the greater part of my course—if,
indeed, so small a number of lectures can be properly
called a course—must be devoted to preliminary
matters, or rather to a statement of those facts and of
those principles which the work itself dwells upon, and
brings more or less directly before us. I have no right
to suppose that all or any of you are naturalists; and
even if you were, the misconceptions and misunder-
standings prevalent even among naturalists on these
matters would make it desirable that I should take the
course I now propose to take,—that I should start from
the beginning,—that I should endeavour to point out
what is the existing state of the organic world—that
I should point out its past condition,—that I should
state what is the precise nature of the undertaking
which Mr. Darwin has taken in hand; that I should
endeavour to show you what are the only methods by
which that undertaking can be brought to an issue, and
to point out to you how far the author of the work in
question has satisfied those conditions, how far he has
not satisfied them, how far they are satisfiable by man,
and how far they are not satisfiable by man. And for
to-night, in taking up the first part of this question,
I shall endeavour to put before you a sort of broad
notion of our knowledge of the condition of the living
world. There are many ways of doing this. I might
deal with it pictorially and graphically. Following the,
example of Humboldt in his “ Aspects of Nature,”
I might endeavour to point out the infinite variety of
organic life in every mode of its existence, with refer-
ence to the variations of climate and the like ; and such

OF ORGANIC NATURE. 7

an attempt would be fraught with interest to us all;
but considering the subject before us, such a course
would not be that best calculated to assist us. In an
argument of this kind we must go further and dig
deeper into the matter; we must endeavour to look
into the foundations of living Nature, if I may so say,
and discover the principles involved in some of her
most secret operations. I propose, therefore, in the
first place, to take some ordinary animal with which
you are all familiar, and, by easily comprehensible and
obvious examples drawn from it, to show what are the
kind of problems which living beings in general lay
before us; and I shall then show you that the same
problems are laid open to us by all kinds of living
beings. But, first, let me say in what sense I have
used the words “organic nature.” In speaking of the
causes which lead to our present knowledge of organic
nature, I have used it almost as an equivalent of the
word “living,” and for this reason,—that in almost ail
living beings you can distinguish several distinct por-
tions set apart to do particular things and work in a
particular way. These are termed “ organs,” and the
whole together is called “organic.” And as it is
universally characteristic of them, this term “‘ organic”
has been very conveniently employed to denote the
whole of living nature,—the whole of the plant world,
and the whole of the animal world.

Few animals can be more familiar to you than that
whose skeleton is shown on this diagram. You need
not bother yourselves with this “ Hquus caballus”’
written under it; that is only the Latin name of it,
and does not make it any better. It simply means the

8 THE PRESENT CONDITION

common Horse. Suppose we wish to understand all
about the Horse. Our first object must be to study
the structure of the animal. The whole of his body
is inclosed within a hide, a skin covered with hair; and
if that hide or skin be taken off, we find a great mass
of flesh, or what is technically called muscle, being
the substance which by its power of contraction enables
the animal to move. These muscles move the hard
parts one upon the other, and so give that strength
and power of motion which renders the Horse so useful
to us in the performance of those services in which we
employ him.

And then, on separating and removing the whole of
this skin and flesh, you have a great series of bones,
hard structures, bound together with ligaments, and
forming the skeleton which is represented here.

In that skeleton there are a number of parts to be
recognized. This long series of bones, beginning from
the skull and ending in the tail, is called the spine, and
these in front are the ribs ; and then there are two pairs
limbs, one before and one behind; and these are what
we all know as the fore-legs and the hind-legs. If we
pursue our researches into the interior of this animal,
we find within the framework of the skeleton a great
cavity, or rather, I should say, two great cavities,—one
cavity beginning in the skull and running through the
neck-bones, along the spine, and ending in the tail,
containing the brain and the spinal marrow, which are
extremely important organs. The second great cavity,
commencing with the mouth, contains the gullet, the
stomach, the long intestine, and all the rest of those
internal apparatus which are essential for digestion ;

OF ORGANIC NATURE. 9

and then in the same great cavity, there are lodged the
heart and all the great vessels going from it; and, be-
sides that, the organs of respiration—the lungs; and
then the kidneys, and the organs of reproduction, and
so on. Let us now endeavour to reduce this notion of a
horse that we now have, to some such kind of simple ex-
pression as can be at once, and without difficulty, retained
in the mind, apart from all minor details. If I make a
transverse section, that is, if 1 were to saw a dead
horse across, [ should find that, if I left out the details,
and supposing I took my section through the anterior
region, and through the fore-limbs, I should have here
this kind of section of the body (Fig. 1). Here would
be the upper part of
the animal—that great
mass of bones that we
spoke of as the spine
fe Bie: 1.) Here I
should have the ali-
mentary canal (0, Fig.
1). Here I should have
the heart (c, Fig. 1);
and then yousee, there »(
would be a kind of Sg

double tube, the whole being inclosed within the
hide; the spinal marrow would be placed in the
upper tube (a, Fig. 1), and in the lower tube (0,
Fig. 1) there would be the alimentary canal and the
heart; and here I shall have the legs proceeding from
each side. For simplicity’s sake, I represent them
merely as stumps (e e, Fig. 1). Now that is a horse—

as mathematicians would say—reduced to its most sim-

i0 THE PRESENT CONDITION

ple expression. Carry that in your minds, if you please,
as a simplified idea of the structure of the Horse. The
considerations which I have now put before you belong
to what we technically call the ‘ Anatomy’ of the Horse.
Now, suppose we go to work upon these several parts,—
flesh and hair, and skin and bone, and lay open these
various organs with our scalpels, and examine them by
means of our magnifying-glasses, and see what we can
make of them. We shall find that the flesh is made
up of bundles of strong fibres. The brain and nerves,
too, we shall find, are made up of fibres, and these
queer-looking things that are called ganglionic cor-
puscles. If we take a slice of the bone and examine
it, we shall find that it is very like this diagram of a
section of the bone of an ostrich, though differing, of
course, in some details; and if we take any part what-
soever of the tissue, and examine it, we shall find it
all has a minute structure, visible only under the
microscope. All these parts constitute microscopic ana-
tomy or ‘ Histology.’ These parts are constantly being
changed; every part is constantly growing, decaying,
and being replaced during the life of the animal. The
‘tissue is constantly replaced by new material; and if
you go back to the young state of the tissue in the
case of muscle, or in the case of skin, or any of the
organs I have mentioned, you will find that they all
come under the same condition. Every one of these
microscopic filaments and fibres (I now speak merely
of the general character of the whole process)—every
one of these parts—could be traced down to some
modification of a tissue which can be readily divided
into little particles of fleshy matter, of that substance

OF ORGANIC NATURE. ll

which is composed of the chemical elements, carbon,
hydrogen, oxygen, and nitrogen, having such a shape
as this (Fig. 2). These particles, into which all
primitive tissues break up, are called
cells. If I were to make a section of
apiece of the skin of my hand, I should
find that it was made up of these cells.
If I examine the fibres which form the Fie. 2.

various organs of all living animals, I should find that
all of them, at one time or other, had been formed out
of a substance consisting of similar elements; so that

you see, just as we reduced the whole body in the gross
to that sort of simple expression given in Fig. 1, so we
may reduce the whole of the microscopic structural
elements to a form of even greater simplicity ; just as
the plan of the whole body may be so represented in a
sense (Fig. 1), so the primary structure of every tissue
may be represented by a mass of cells (Fig. 2).
Having thus, in this sort of general way, sketched
to you what I may call, perhaps, the architecture of
the body of the Horse (what we term technically its
Morphology), I must now turn to another aspect. A
horse is not a mere dead structure: it is an active,
living, working machine. Hitherto we have, as it were,
been looking at a steam-engine with the fires out, and
nothing in the boiler; but the body of the living
animal is a beautifully-formed active machine, and
every part has its different work to do in the working
of that machine, which is what we call its life. The
Horse, if you see him after his day’s work is done, is
cropping the grass in the fields, as it may be, or munch-
ing the oats in his stable. What is he doing? His

12 THE PRESENT CONDITION

jaws are working as a mill—and a very complex mill
too—grinding the corn, or crushing the grass to a
pulp. As soon as that operation has taken place,
the food is passed down to the stomach, and there it is
mixed with the chemical fluid called the gastric juice,
a substance which has the peculiar property of making
soluble and dissolving out the nutritious matter in the
grass, and leaving behind those parts which are not
nutritious ; so that you have, first, the mill, then a sort
of chemical digester; and then the food, thus par-
tially dissolved, is carried back by the muscular con-
tractions of the intestines into the hinder parts of the
body, while the soluble portions are taken up into
the blood. The blood is contained in a vast system of
pipes, spreading through the whole body, connected
with a force-pump,—the heart,—which, by its position
and by the contractions of its valves, keeps the blood
constantly circulating in one direction, never allowing it
to rest; and then, by means of this circulation of the
blood, laden as it is with the products of digestion, the
skin, the flesh, the hair, and every other part of the
body, draws from it that which it wants, and every one
of these organs derives those materials which are
necessary to enable it to do its work.

The action of each of these organs, the performance
of each of these various duties, involve in their operation
a continual absorption of the matters necessary for their
support, from the blood, and a constant formation of
waste products, which are returned to the blood, and
conveyed by it to the lungs and the kidneys, which are
organs that have allotted to them the office of extract-
ing, separating, and getting rid of these waste pro-

OF ORGANIC NATURE. 13

ducts; and thus the general nourishment, labour, and
repair of the whole machine is kept up with order and
regularity. But not only is it a’machine which feeds
and appropriates to its own support the nourishment
necessary to its existence—it is an engine for loco-
motive purposes. The Horse desires to go from one
place to another; and to enable it to do this, it has
those strong contractile bundles of muscles attached
to the bones of its limbs, which are put in motion by
means of a sort of telegraphic apparatus formed by
the brain and the great spinal cord running through
the spine or backbone; and to this spinal cord are
attached a number of fibres termed nerves, which
proceed to all parts of the structure. By means of
these the eyes, nose, tongue, and skin—all the organs
of perception—transmit impressions or sensations to
the brain, which acts as a sort of great central tele-
graph-office, receiving impressions and sending mes
sages to all parts of the body, and putting in motion
the muscles necessary to accomplish any movement
that may be desired. So that here you have an ex-
tremely complex and beautifully-proportioned machine
with all its parts working harmoniously together
towards one common object—the preservation of the
life of the animal.

Now, note this: the Horse makes up its waste by
feeding, and its food is grass or oats, or perhaps other
vegetable products; therefore, in the long run, the
source of all this complex machinery lies in the vege-
table kingdom. But where does the grass, or the
oat, or any other plant, obtain this nourishing food-
producing material? At first it is a little seed, which

14 THE PRESENT CONDITION

soon begins to draw into itself from the earth and the
surrounding air matters which in themselves contain no
vital properties whatever; it absorbs into its own sub-
stance water, an inorganic body; it draws into its sub-
stance carbonicacid, an inorganic matter; and ammonia,
another inorganic matter, found in the air; and then,
by some wonderful chemical process, the details of
which chemists do not yet understand, though they are
near foreshadowing them, it combines them into one
substance, which is known to us as ‘Protein, a
complex compound of carbon, hydrogen, oxygen, and
nitrogen, which alone possesses the property of mani-
festing vitality and of permanently supporting animal
life. So that, you see, the waste products of the
animal economy, the effete materials which are con-
tinually being thrown off by all living beings, in
the form of organic matters, are constantly replaced
by supplies of the necessary repairing and rebuilding
materials drawn from the plants, which in their turn
manufacture them, so to speak, by a mysterious com-
bination of those same inorganic materials.

Let us trace out the history of the Horse in another
direction. After a certain time, as the result of sick-
ness or disease, the effect of accident, or the consequence
of old age, sooner or later, the animal dies. The mul-
titudinous operations of this beautiful mechanism flag
in their performance, the Horse loses its vigour, and
after passing through the curious series of changes
comprised in its formation and preservation, it finally
decays, and ends its life by going back into that inor-
ganic world from which all but an inappreciable frac-
tion of its substance was derived. Its bones become

OF ORGANIC NATURE. 15

mere carbonate and phosphate of lime; the matter of
its flesh, and of its other parts, becomes, in the long run,
converted into carbonic acid, into water, and into am-
monia. You will now, perhaps, understand the curious
relation of the animal with the plant, of the organic
with the inorganic world, which is shown in this
diagram.
INORGANIC WORLD.

Carbonic Acid. Water. Ammonia. Salines.

ies - \
Cael

Ps \
ae = : IC \
74 — i WATER |
SALINES

VEGETABLE WORLD. (Fig. 3.) ANIMAL WORLD.

The plant gathers these inorganic materials together
and makes them up into its own substance. The
animal eats the plant and appropriates the nutritious
portions to its own sustenance, rejects and gets rid
of the useless matters; and, finally, the animal itself
dies, and its whole body is decomposed and veturned
into the inorganic world. There is thus a constant
circulation from one to the other, a continual formation
of organic life from inorganic matters, and as constant
a return of living bodies to the inorganic world; so
that the materials of which our bodies are composed
are largely, in all probability, the substances which con-
stituted the matter of long extinct creations, but which
have in the interval constituted a part of the imorganic
world.

16 THE PRESENT CONDITION

Thus we come to the conclusion, strange at first
sight, that the Marrer constituting the living world is
identical with that which forms the inorganic world.
And not less true is it that, remarkable as are the
powers or, in other words, as are the Forczs which are
exerted by living beings, yet all these forces are either
identical with those which exist in the inorganic world,
or they are convertible into them; I mean in just the
same sense as the researches of physical philosophers
have shown that heat is convertible into electricity,
that electricity is convertible into magnetism, magne-
tism into mechanical force or chemical force, and any
one of them with the other, each being measurable
in terms of the other,—even so, I say, that great law is
applicable to the living world. Consider why is the
skeleton of this horse capable of supporting the masses
of flesh and the various organs forming the living body,
unless it is because of the action of the same forces of
cohesion which combines together the particles of
matter composing this piece of chalk? What is there
in the muscular contractile power of the animal but the
force which is expressible, and which is in a certain
sense convertible, into the force of gravity which it
overcomes? Or, if you go to more hidden processes,
in what does the process of digestion differ from those
processes which are carried on in the laboratory of the
chemist? Even if we take the most recondite and
most complex operations of animal life—those of the
nervous system, these of late years have been shown to
be—I do not say identical in any sense with the elec-
trical processes—but this has been shown, that they are
in some way or other associated with them; that is to

OF ORGANIC NATURE. 17

say, that every amount of nervous action is accompanied
by a certain amount of electrical disturbance in the
particles of the nerves in which that nervous action is
carried on. In this way the nervous action is related
to electricity in the same way that heat is related to
electricity ; and the same sort of argument which
demonstrates the two latter to be related to one an-
other shows that the nervous forces are correlated to
electricity ; for the experiments of M. Dubois Reymond
and others have shown that whenever a nerve is in a
state of excitement, sending a message to the muscles
or conveying an impression to the brain, there is a
disturbance of the electrical condition of that nerve
which does not exist at other times; and there are a
number of other facts and phenomena of that sort ; so
that we come to the broad conclusion that not only
as to living matter itself, but as to the forces that
matter exerts, there is a close relationship between the
organic and the inorganic world—the difference between
them arising from the diverse combination and dis-
position of identical forces, and not from any primary
diversity, so far as we can see.

I said just now that the Horse eventually died and
became converted into the same inorganic substances
from whence all but an inappreciable fraction of its
substance demonstrably originated, so that the actual
wanderings of matter are as remarkable as the trans-
migrations of the soul fabled by Indian tradition. But
before death has occurred, in the one sex or the other,
and in fact in both, certain products or parts of the
organism have been set free, certain parts of the
organisms of the two sexes have come into contact

18 THE PRESENT CONDITION

with one another, and from that conjunction, from that
union which then takes place, there results the forma-
tion of a new being. At stated times the mare, from a
particular part of the interior of her body, called the
evary, gets rid of a minute particle of matter comparable
in all essential respects with that which we called a cell
a little while since, which cell contains a kind of nucleus
in its centre, surrounded by a clear space and by a
viscid mass of protein substance (Fig. 2); and though
it is different in appearance from the eggs which we are
mostly acquainted with, it is really an egg. After a
time this minute particle of matter, which may only be
a small fraction of a grain in weight, undergoes a series
of changes,— wonderful, complex changes. Finally, upon
its surface there is fashioned a little elevation, which
afterwards becomes divided and marked by a groove.
The lateral boundaries of the groove extend upwards
and downwards, and at length give rise to a double
tube. In the upper smaller tube the spinal marrow
and brain are fashioned; in the lower, the alimentary
canal and heart, and at length two pairs of buds shoot
out at the sides of the body, which are the rudiments
of the limbs. In fact a true drawing of a section of the
embryo in this state would in all essential respects
resemble that diagram of a horse reduced to its simplest
expression, which I first placed before you (Fig. 1).
Slowly and gradually these changes take place. The
whole of the body, at first, can be broken up into “cells,”
which become in one place metamorphosed into muscle,
—in another place into gristle and bone,—in another
place into fibrous tissue,—and in another into hair;
every part becoming gradually and slowly fashioned, as

OF ORGANIC NATURE. 19

if there were an artificer at work in each of these complex
structures that we have mentioned. This embryo, as
it is called, then passes into other conditions. This dia-
gram represents the embryo of a dog; and I should tell
you that there is a time when the embryos of neither
dog, nor horse, nor porpoise, nor monkey, nor man, can
be distinguished by any essential feature one from the
other; there is a time when they each and all of them
resemble this one of the Dog. But as development
advances, all the parts acquire their speciality, till at
length you have the embryo converted into the form of
the parent from which it started. So that you see,
this living animal, this horse, begins its existence as
a minute particle of introgenous matter, which, being
supplied with nutriment (derived, as I have shown,
from the inorganic world), grows up according
to the special type and construction of its parents,
works and undergoes a constant waste, and that waste
is made good by nutriment derived from the inorganic
world ; the waste given off in this way being directly
added to the inorganic world; and eventually the
animal itself dies, and, by the process of decomposi-
tion, its whole body is returned to those conditions
of inorganic matter in which its substance origi-
nated.

This, then, is that which is true of every living
form, from the lowest plant to the highest animal—to
man himself. You might define the life of every one
in exactly the same terms as those which I have now
used; the difference between the highest and the
lowest being simply in the complexity of the develop-
mental changes, the variety of the structural forms,

20 THE PRESENT CONDITION

the diversity of the physiological functions which are
exerted by each.

If I were to take an oak tree as a specimen of the
plant world, I should find that it originated in an
acorn, which, too, commenced in a cell; the acorn is
placed in the ground, and it very speedily begins to
absorb the inorganic matters I have named, adds
enormously to its bulk, and we can see it, year after
year, extending itself upward and downward, attract-
ing and appropriating to itself inorganic materials,
which it vivifies, and eventually, as it ripens, gives off
its own proper acorns, which again run the same
course. But I need not multiply examples,—from the
highest to the lowest the essential features of life are
the same, as I have described in each of these cases.

So much, then, for these particular features of the
organic world, which you can understand and com-
prehend, so long as you confine yourself to one sort of
living being, and study that only.

But, as you know, horses are not the only living
creatures in the world; and again, horses, like all
other animals, have certain limits—are confined to a
certain area on the surface of the earth on which we
live,—and, as that is the simpler matter, I may take
that first. In its wild state, and before the discovery
of America, when the natural state of things was
interfered with by the Spaniards, the Horse was only to
be found in parts of the earth which are known to
geographers as the Old World; that is to say, you
might meet with horses in Europe, Asia, or Africa ;
but there were none in Australia, and there were none
whatsoever in the whole continent of America, from

OF ORGANIC NATURE. 21

Labrador down to Cape Horn. This is an empirical
fact, and it is what is called, stated in the way I have
given it you, the ‘Geographical Distribution’ of the
Horse.

Why horses should be found in Europe, Asia, and
Africa, and not in America, is not obvious; the expla-
nation that the conditions of life in America are un-
favourable to their existence, and that, therefore, they
had not been created there, evidently does not apply ;
for when the invading Spaniards, or our own yeomen
farmers, conveyed horses to these countries for their
own use, they were found to thrive well and multiply
very rapidly ; and many are even now running wild in
those countries, and in a perfectly natural condition.
Now, suppose we were to do for every animal what we
have here done for the Horse,—that is, to mark off and
distinguish the particular district or region to which
each belonged ; and supposing we tabulated all these
results, that would be called the Geographical Distri-
bution of animals, while a corresponding study of
plants would yield as a result the Geographical Distri-
bution of plants.

I pass on from that now, as I merely wished to
explain to you what I meant by the use of the term
‘Geographical Distribution.’ As I said, there is an-
other aspect, and a much more important one, and
that is, the relations of the various animals to one
another. The Horse is a very well-defined matter-of-
fact sort of animal, and we are all pretty familiar with
its structure. I dare say it may have struck you,
that it resembles very much no other member of the
animal kingdom, except perhaps the Zebra or the Ass.

Oe THE PRESENT CONDITION

But let me ask you to look along these diagrams.
Here is the skeleton of the Horse; and here the
skeleton of the Dog. You will notice that we have
in the Horse a skull, a backbone and ribs, shoulder-
blades and haunch-bones. In the fore-limb, one
upper arm-bone, two fore arm-bones, wrist-bones
(wrongly called knee), and middle hand-bones, ending
in the three bones of a finger, the last of which is
sheathed in the horny hoof of the fore-foot: in the
hind-limb, one thigh-bone, two leg-bones, ankle-bones,
and middle foot-bones, ending in the three bones of a
toe, the last of which is encased in the hoof of the
hind-foot. Now turn to the Dog’s skeleton. We find
identically the same bones, but more of them, there
being more toes in each foot, and hence more
toe-bones.

Well, that is a very curious thing! The fact is
that the Dog and the Horse—when one gets a look at
them without the outward impediments of the skin—
are found to be made in very much the same sort of
fashion. And if I were to make a transverse section of
the Dog, I should find the same organs that I have
already shown you as forming parts of the Horse.
Well, here is another skeleton—that of a kind of Lemur
—yousee he has just the same bones; and if I were to
make a transverse section of it, it would be just the
same again. In your mind’s eye turn him round, so as
to put his backbone in a position inclined obliquely
upwards and forwards, just as in the next three dia-
grams, which represent the skeletons of an Orang, a
Chimpanzee, a Gorilla, and you find you have no trouble
in identifying the bones throughout ; and lastly turn to

OF ORGANIC NATURE. 23

the end of the series, the diagram representing a man’s
skeleton, and still you find no great structural feature
essentially altered. There are the same bones in the
same relations. From the Horse we pass on and on, with
gradual steps, until we arrive at last at the highest known
forms. On the other hand, take the other line of dia-
grams, and pass from the Horse downwards in the scale
to this fish; and still, though the modifications are vastly
greater, the essential framework of the organization
remains unchanged. Here, for instance, is a Porpoise ;
here is its strong backbone, with the cavity running
through it, which contains the spinal cord; here are
the ribs, here the shoulder-blade; here is the little
short upper-arm bone, here are the two forearm bones.
the wrist-bone, and the finger-bones.

Strange, is it not, that the Porpoise should have in
this queer-looking affair—its flapper (as it is called),
the same fundamental elements as the fore-leg of the
Horse or the Dog, or the Ape or Man; and here you
will notice a very curious thing,—the hinder limbs are
absent. Now, let us make another jump. Let us go
to the Codfish: here you see is the forearm, in this
large pectoral fin—carrying your mind’s eye onward
from the flapper of the Porpoise. And here you have
the hinder limbs restored in the shape of these ventral
fins. If I were to make a transverse section of this, I
should find just the same organs that we have before
noticed. So that, you see, there comes out this strange
conclusion as the result of our investigations, that the
Horse, when examined and compared with other ani-
mals, is found by no means to stand alone in nature ;
but that there are an enormous number of other

24 THE PRESENT CONDITION

creatures which have backbones, ribs, and legs, and
other parts arranged inthe same general manner, and
in all their formation exhibiting the same broad pecu-
liarities.

Iam sure that you cannot have followed me even
in this extremely elementary exposition of the struc-
tural relations of animals, without seeing what I have
been driving at all through, which is, to show you that,
step by step, naturalists have come to the idea of a
unity of plan, or conformity of construction, among
animals which appeared at first sight to be extremely
dissimilar.

And here you have evidence of such a unity of plan
among all the animals which have backbones, and
which we technically call Vertebrata. But there are
multitudes of other animals, such as crabs, lobsters,
spiders, and so on, which we term Annulosa. In these
I could not point out to you the parts that correspond
with those of the Horse,--the backbone, for instance,—
as they are constructed upon a very different prin-
ciple, which is also common to all of them; that is to
say, the Lobster, the Spider, and the Centipede, have
a common plan running through their whole arrange-
ment, in just the same way that the Horse, the Dog,
and the Porpoise assimilate to each other.

Yet other creatures—whelks, cuttlefishes, oysters,
snails, and all their tribe (Mollusca)—resemble one
another in the same way, but differ from both Verte-
brata and Annulosa ; and the like is true of the animals
called Coelenterata (Polypes) and Protozoa (animalcules
and sponges).

Now, by pursuing this sort of comparison, naturalists

OF ORGANIC NATURE. 25

have arrived at the conviction that there are,—some
think five, and some seven,—but certainly not more
than the latter number—and perhaps it is simpler to
assume five —distinct plans or constructions in the
whole of the animal world; and that the hundreds of
thousands of species of creatures on the surface of the
earth, are all reducible to those five, or, at most, seven,
plans of organization.

But can we go no further than that? When one
has got so far, one is tempted to go on a step and in-
quire whether we cannot go back yet further and bring
down the whole to modifications of one primordial unit.
The anatomist cannot do this; but if he call to his aid
the study of development, he can do it. For we shall
find that, distinct as those plans are, whether it bea
porpoise or man, or lobster, or any of those other kinds
I have mentioned, every one begins its existence with
one and the same primitive form,—that of the egg,
consisting, as we have seen, of a introgenous substance,
having a small particle or nucleus in the centre of it.
_ Furthermore, the earlier changes of each are sub-
stantially the same. And it is in this that lies that
true “unity of organization” of the animal kingdom
which has been guessed at and fancied for many
years ; but which it has been left to the present time
to be demonstrated by the careful study of develop-
ment. But is it possible to go another step further
still, and to show that in the same way the whole of
the organic world is reducible to one primitive con-
dition of form? Is there among the plants the same
primitive form of organization, and is that identical
with that of the animal kingdom? The reply to that

26 THE PRESENT CONDITION

question, too, is not uncertain or doubtful. It is now
proved that every plant begins its existence under the
same form; that is to say, in that of a cell—a particle
of introgenous matter having substantially the same
conditions. So that if you trace back the oak to its first
germ, or a man, or a horse, or lobster, or oyster, or any
other animal you choose to name, you shall find each
and all of these commencing their existence in forms
essentially similar to each other: and, furthermore,
that the first processes of growth, and many of the
subsequent modifications, are essentially the same in
principle in almost all.

In conclusion, let me, in a few words, recapitulate
the positions which I have laid down. And you must
understand that I have not been talking mere theory ;
Ihave been speaking of matters which are as plainly
demonstrable as the commonest propositions of Euclid—
of facts that must form the basis of all speculations
and beliefs in Biological science. We have gradually
traced down all organic forms, or, in other words, we
have analyzed the present condition of animated nature,
until we found that each species took its origin in a
form similar to that under which all the others com-
mence their existence. We have found the whole of
the vast array of living forms, with which we are
surrounded, constantly growing, increasing, decaying,
and disappearing; the animal constantly attracting,
modifying, and applying to its sustenance the matter
of the vegetable kingdom, which derived its support
from the absorption and conversion of inorganic matter.
And so constant and universal is this absorption, waste,
and reproduction, that it may be said with perfect

OF ORGANIC NATURE. 24

certainty that there is left in no one of our bodies at
the present moment a millionth part of the matter
of which they were originally formed! We have seen,
again, that not only is the living matter derived from
the inorganic world, but that the forces of that matter
are all of them correlative with and convertible into
those of inorganic nature.

This, for our present purposes, is the best view of
the present condition of organic nature which I can
lay before you: it gives you the great outlines of a
vast picture, which you must fill up by your own
study.

In the next lecture I shall endeavour in the same
way to go back into the past, and to sketch in the
same broad manner the history of life in epochs pre-
ceding our own.

vies at wey ia "

ob ‘ ok ee te tiled elt
(alld ta ai
eas Pat hsci)

18 w i My % I} sosauae
peed 9 Bh iG wld we vis de fi.

ce Git Pha ey BNA

ee RATE toh hit } reap ut 6 pinta te i

if pants { 4, Mi a eae f wii i P

eC U Rie

~oo————

THE PAST CONDITION OF ORGANIC
NATURE.

In the lecture which I delivered last Monday evening,
{ endeavoured to sketch in a very brief manner, but as
well as the time at my disposal would permit, the pre-
sent condition of organic nature, meaning by that
large title simply an indication of the great, broad,
and general principles which are to be discovered by
those who look attentively at the phenomena of organic
nature as at present displayed. The general result
of our investigations might be summed up thus: we
found that the multiplicity of the forms of animal life,
great as that may be, may be reduced to a com-
paratively few primitive plans or types of construction ;
that a further study of the development of those dif-
ferent forms revealed to us that they were again
reducible, until we at last brought the infinite diversity
of animal, and even vegetable life, down to the primor-
dial form of a single cell.

We found that our analysis of the organic world,
whether animals or plants, showed, in the long run, that
they might both be reduced into, and were, in fact, com-
posed of the same constituents. And we saw that the

30 THE PAST CONDITION

plant obtained the materials constituting its substance
by a peculiar combination of matters belonging entirely
to the inorganic world; that, then, the animal was con-
stantly appropriating the nitrogenous matters of the
plant to its own nourishment, and returning them back
to the inorganic world, in what we spoke of as its
waste; and that, finally, when the animal ceased to
exist, the constituents of its body were dissolved and
transmitted to that imorganic world whence they had
been at first abstracted. Thus we saw in both the
blade of grass and the horse but the same elements
differently combined and arranged. We discovered a
continual circulation going on,—the plant drawing in
the elements of inorganic nature and combining them
into food for the animal creation; the animal bor-
rowing from the plant the matter for its own support,
giving off during its life products which returned im-
mediately to the inorganic world ; and that, eventually,
the constituent materials of the whole structure of both
animals and plants were thus returned to their original
source: there was a constant passage from one state of
existence to another, and a returning back again.

Lastly, when we endeavoured to form some notion of
the nature of the forces exercised by living beings, we
discovered that they—if not capable of being subjected
to the same minute analysis as the constituents of those
beings themselves—that they were correlative with—
that they were the equivalents of the forces of inorganic
nature—that they were, in the sense in which the term
is now used, convertible with them. That was our
general result.

And now, leaving the Present, I must endeavour

OF ORGANIC NATURE. 31

in the same manner to put before you the facts that
are to be discovered in the Past history of the living
world, in the past conditions of organic nature. We
have, to-night, to deal with the facts of that history
—a history involving periods of time before which our
mere human records sink into utter insignificance—a
history the variety and physical magnitude of whose
events cannot even be foreshadowed by the history of
human life and human phenomena—a history of the
most varied and complex character.

We must deal with the history, then, in the first
place, as we should deal with all other histories.
The historical student knows that his first business
should be to inquire into the validity of his evi-
dence, and the nature of the record in which the
evidence is contained, that he may be able to form
a proper estimate of the correctness of the conclusions
which have been drawn from that evidence. So,
here, we must pass, in the first place, to the considera-
tion of a matter which may seem foreign to the question
under discussion. We must dwell upon the nature of
the records, and the credibility of the evidence they
contain; we must look to the completeness or incom-
pleteness of those records themselves, before we turn
to that which they contain and reveal. The question
of the credibility of the history, happily for us, will not
require much consideration, for, in this history, unlike
those of human origin, there can be no cavilling, no
differences as to the reality and truth of the facts of
which it is made up; the facts state themselves, and
are laid out clearly before us.

But, although one of the greatest difficulties of

32 THE PAST CONDITION

the historical student is cleared out of our path, there
are other difficulties—difficulties in rightly inter-
preting the facts as they are presented to us—which
may be compared with the greatest difficulties of any
other kinds of historical study.

What is this record of the past history of the globe,
and what are the questions which are involved in an
inquiry into its completeness or incompleteness? That
record is composed of mud; and the question which we
have to investigate this evening resolves itself into a
question of the formation of mud. You may think, per-
haps, that this is a vast step—of almost from the sublime
to the ridiculous—from the contemplation of the history
of the past ages of the world’s existence to the con-
sideration of the history of the formation of mud!
But, in nature, there is nothing mean and unworthy of
attention; there is nothing ridiculous or contemptible
in any of her works; and this inquiry, you will soon
see, I hope, takes us to the very root and foundations
of our subject.

How, then, is mud formed? Always, with some
trifling exception, which I need not consider now—
always, as the result of the action of water, wear-
ing down and disintegrating the surface of the
earth and rocks with which it comes in contact—
pounding and grinding it down, and carrying the par-
ticles away to places where, they cease to be disturbed
by this mechanical action, and where they can subside
and rest. For the ocean, urged by winds, washes,
as we know, a long extent of coast, and every wave,
loaded as it is with particles of sand and gravel as it
breaks upon the shore, does something towards the dis-

OF ORGANIC NATURE. 33

integrating process. And thus, slowly but surely, the
hardest rocks are gradually ground down to a powdery
substance ; and the mud thus formed, coarser or finer,
as the case may be, is carried by the rush of the
tides, or currents, till it reaches the comparatively
deeper parts of the ocean, in which it can sink to
the bottom, that is, to parts where there is a depth of
about fourteen or fifteen fathoms, a depth at which the
water is, usually, nearly motionless, and in which, of
course, the finer particles of this detritus, or mud as
we call it, sinks to the bottom.

Or, again, if you take a river, rushing down from
its mountain sources, brawling over the stones and
rocks that intersect its path, loosening, removing,
and carrying with it in its downward course the
pebbles and lighter matters from its banks, it crushes
and pounds down the rocks and earths in precisely
the same way as the wearing action of the sea waves.
The matters forming the deposit are torn from the
mountain-side and whirled impetuously into the val-
ley, more slowly over the plain, thence into the
estuary, and from the estuary they are swept into
the sea. The coarser and heavier fragments are ob-
viously deposited first, that is, as soon as the current
begins to lose its force by becoming amalgamated
with the stiller depths of the ocean, but the finer and
lighter particles are carried further on, and eventually
deposited in a deeper and stiller portion of the ocean.

It clearly follows from this that mud gives us a
chronology ; for it is evident that supposing this, which
i now sketch, to be the sea bottom, and supposing this
to be a coast-line; from the washing action of the

34 THE PAST CONDITION

sea upon the rock, wearing and grinding it down
into a sediment of mud, the mud will be carried
down, and at length, deposited in the deeper parts of
this sea bottom, where it will form a layer; and
then, while that first layer is hardening, other mud
which is coming from the same source will, of course,
be carried to the same place; and, as it is quite im-
possible for it to get beneath the layer already there,
it deposits itself above it, and forms another layer, and
in that way you gradually have layers of mud con-
stantly forming and hardening one above the other,
and conveying a record of time.

It is a necessary result of the operation of the law of
gravitation that the uppermost layer shall be the
youngest and the lowest the oldest, and that the differ-
ent beds shall be older at any particular point or spot
in exactly the ratio of their depth from the surface.
So that if they were upheaved afterwards, and you had
a series of these different layers of mud, converted into
sandstone, or limestone, as the case might be, you might
be sure that the bottom layer was deposited first, and
that the upper layers were formed afterwards. Here,
you see, is the first step in the history—these layers
of mud give us an idea of time.

The whole surface of the earth,—I speak broadly,
and leave out minor qualifications,—is made up of such
layers of mud, so hard, the majority of them, that we
call them rock, whether limestone or sandstone, or other
varieties of rock. And, seeing that every part of the
crust of the earth is made up in this way, you might
think that the determination of the chronology, the
fixing of the time which it has taken to form this crust

OF ORGANIC NATURE. 35

is a comparatively simple matter. Take a broad ave-
rage, ascertain how fast the mud is deposited upon the
bottom of the sea, or in the estuary of rivers; take it
to be an inch, or two, or three inches a year, or what-
ever you may roughly estimate it at ; then take the total
thickness of the whole series of stratified rocks, which
geologists estimate at twelve or thirteen miles, or about
seventy thousand feet, make a sum in short division,
divide the total thickness by that of the quantity
deposited in one year, and the result will, of course,
give you the number of years which the crust has taken
to form.

Truly, that looks a very simple process! It would
be so except for certain difficulties, the very first
of which is that of finding how rapidly sediments
are deposited; but the main difficulty—a difficulty
which renders any certain calculations of such a
matter out of the question—is this, the sea-bottom on
which the deposit takes place is continually shifting.

Instead of the surface of the earth being that stable,
fixed thing that it is popularly believed to be, being,
in common parlance, the very emblem of fixity itself,
it is incessantly moving, and is, in fact, as unstable as
the surface of the sea, except that its undulations are
infinitely slower and enormously higher and deeper.

Now, what is the effect of this oscillation? Take
the case to which I have previously referred. The finer
or coarser sediments that are carried down by the
current of the river, will only be carried out a certain
distance, and eventually, as we have already seen, on
reaching the stiller part of the ocean, will be depo-
sited at the bottom.

36 THE PAST CONDITION

Let C y (Fig. 4) be the sea-bottom, y D the shore,
a y the sea-level, then the coarser deposit will subside

Fic. 4.

over the region B, the finer over A, while beyond
A there will be no deposit at all; and, consequently,
no record will be kept, simply because no deposit
is going on. Now, suppose that the whole land,
C, D, which we have regarded as stationary, goes
down, as it does so, both A and B go further out
from the shore, which will be at y!, 2! y, being the
new sea-level. The consequence will be that the
layer of mud (A), being now, for the most part, fur-
ther than the force of the current is strong enough
to convey even the finest débris, will, of course,
receive no more deposits, and having attained a
certain thickness will now grow no thicker.

We should be misled in taking the thickness of that
layer, whenever it may be exposed to our view, as @
record of time in the manner in which we are now re-
garding this subject, as it would give us only an
imperfect and partial record it would seem to represent
too short a period of time.

Suppose, on the other hand, that the land (C D)
had gone on rising slowly and gradually—say an
inch or two inches in the course of a century,—

OF ORGANIC NATURE. o7

what would be the practical effect of that movement ?
Why, that the sediment A and B which has been
already deposited, would eventually be brought nearer to
the shore-level, and again subjected to the wear and tear
of the sea; and directly the sea begins to act upon it,
it would of course soon cut up and carry it away, to
a greater or less extent, to be re-deposited further out.
Well, as there is, in all probability, not one single
spot on the whole surface of the earth, which has not
been up and down in this way a great many times, it
follows that the thickness of the deposits formed at
any particular spot cannot be taken (even sup-
posing we had at first obtained correct data as to
the rate at which they took place), as affording reli-
able information as to the period of time occupied
in its deposit. So that you see it is absolutely ne-
cessary from these facts, seeing that our record
entirely consists of accumulations of mud, superim-
posed one on the other ; seeing in the next place that
any particular spots on which accumulations have
occurred, have been constantly moving up and down,
and sometimes out of the reach of a deposit, and at
other times its own deposit broken up and carried
away, it follows that our record must be in the highest
degree imperfect, and we have hardly a trace left of
thick deposits, or any definite knowledge of the area
that they occupied in a great many cases. And mark
this! That supposing even that the whole surface of
the earth had been accessible to the geologist,—that man
had had access to every part of the earth, and had made
sections of the whole, and put them all together,—
even then his record must of necessity be imperfect.

38 THE PAST CONDITION

But to how much has man really access? If you
will look at this Map you will see that it repre-
sents the proportion of the sea to the earth: this
coloured part indicates all the dry land, and this other
portion is the water. You will notice at once that the
water covers three-fifths of the whole surface of the
globe, and has covered it in the same manner ever
since man has kept any record of his own observations,
to say nothing of the minute period during which
he has cultivated geological inquiry. So that three-
fifths of the surface of the earth is shut out from
us because it is under the sea. Let us look at the
other two-fifths, and see what are the countries in
which anything that may be termed searching geolo-
gical inquiry has been carried out: a good deal of
France, Germany, and Great Britain and Ireland, bits of
Spain, of Italy, and of Russia, have been examined, but
of the whole great mass of Africa, except parts of the
southern extremity, we know next to nothing; little bits
of India, but of the greater part of the Asiatic continent
nothing; bits of the Northern American States and of
Canada, but of the greater part of the continent of
North America, and in still larger proportion, of South
America, nothing !

Under these circumstances, it follows that even with
reference to that kind of imperfect information which we
can possess, it is only of about the ten-thousandth part
of the accessible parts of the earth that has been ex-
amined properly. Therefore, it is with justice that the
most thoughtful of those who are concerned in these in-
quiries insist continually upon the imperfection of the
geological record; for, I repeat, it is absolutely necessary,

OF ORGANIC NATURE, 39

from the nature of things, that that record should be
of the most fragmentary and imperfect character.
Unfortunately this circumstance has been constantly
forgotten. Men of science, like young colts in a fresh
pasture, are apt to be exhilarated on being turned
into a new field of inquiry, and to go off at a hand-
gallop, in total disregard of hedges and ditches, losing
sight of the real limitation of their inquiries, and
to forget the extreme imperfection of what is really
known. Geologists have imagined that they could tell
us what was going on at all parts of the earth’s surface
during a given epoch; they have talked of this deposit
being contemporaneous with that deposit, until, from
our little local histories of the changes at limited
spots of the earth’s surface, they have constructed a
universal history of the globe as full of wonders and
portents as any other story of antiquity.

But what does this attempt to construct a universal
history of the globe imply? It implies that we shall
not only have a precise knowledge of the events which
have occurred at any particular point, but that we
shall be able to say what events, at any one spot,
took place at the same time with those at other spots.

Let us see how far that is in the nature of things
practicable. Suppose that here I make a section of the
Lake of Killarney, and here the section of another
lake—that of Loch Lomond in Scotland for instance.
The rivers that flow into them are constantly carrying
down deposits of mud, and beds, or strata, are being as
constantly formed, one above the other, at the bottom
of those lakes. Now, there is not a shadow of doubt
that in these two lakes the upper beds are all older

40 THE PAST CONDITION

than the lower—there is no doubt about that; but
what does this tell us about the age of any given bed
in Loch Lomond, as compared with that of any
given bed in the Lake of Killarney? It is, indeed,
obvious that if any two sets of deposits are separated
and discontinuous, there is absolutely no means what-
ever given you by the nature of the deposit of saying
whether one is much younger or older than the
other; but you may say, as many have said and think,
that the case is very much altered if the beds which
we are comparing are continuous. Suppose two beds
of mud hardened into rock,—A and B are seen in
section. (Fig. 5.)

Well, you say, it is admitted that the lower-
most bed is always the older. Very well; B, there
fore, is older than A. No doubt, as a whole, it

Fic. 5.

is so; or if any parts of the two beds which are in
the same vertical line are compared, it is so. But
suppose you take what seems a very natural step
further, and say that the part a of the bed A is
younger than the part 4 of the bed B. Is this sound
reasoning? If you find any record of changes taking
place at 6, did they occur before any events which
took place while a was being deposited? It looks all

OF ORGANIC NATURE. 4l

very plain sailing, indeed, to say that they did; and yet
there is no proof of anything of the kind. As the
former Director of this Institution, Sir H. De la Beche,
long ago showed, this reasoning may involve an entire
fallacy. It is extremely possible that @ may have been
deposited ages before b. It is very easy to understand
how that can be. To return to Fig. 4; when A and B were
deposited, they were substantially contemporaneous ;
A being simply the finer deposit, and B the coarser of
the same detritus or waste of land. Now suppose that
that sea-bottom goes down (as shown in Fig. 4), so that
the first deposit is carried no farther than a, forming
the bed A!, and the coarse no farther than 0, forming
the bed B?, the result will be the formation of two con-
tinuous beds, one of fine sediment (A A’) over-lapping
another of coarse sediment (B B'), Now suppose the
whole sea-bottom is raised up, and a section exposed
about the point A?; no doubt, at this spot, the upper
bed is younger than the lower. But we should ob-
viously greatly err if we concluded that the mass of
the upper bed at A was younger than the lower bed
at B; for we have just seen that they are contem-
poraneous deposits. Still more should we be in error
if we supposed the upper bed at A to be younger than
the continuation of the lower bed at B!; for A was
deposited long before B'. In fine, if, instead of com-
paring immediately adjacent parts of two beds, one
of which lies upon another, we compare distant parts,
it is quite possible that the upper may be any number
of years older than the under, and the under any
number of years younger than the upper.

Now you must not suppose that I put this before

49 THE PAST CONDITION

you for the purpose of raising a paradoxical difficulty ;
the fact is, that the great mass of deposits have taken
place in sea-bottoms which are gradually sinking, and
have been formed under the very conditions I am here
supposing.

Do not run away with the notion that this subverts
the principle I laid down at first. The error lies in
extending a principle which is perfectly applicable to
deposits in the same vertical line to deposits which are
not in that relation to one another.

It is in consequence of circumstances of this kind, and
of others that I might mention to you, that our con-
clusions on and interpretations of the record are really
and strictly only valid so long as we confine ourselves
to one vertical section. I do not mean to tell you that
there are no qualifying circumstances, so that, even
in very considerable areas, we may safely speak of
conformably superimposed beds being older or younger
than others at many different points. But we can
never be quite sure in coming to that conclusion,
and especially we cannot be sure if there is any
break in their continuity, or any very great distance
between the points to be compared.

Well now, so much for the record itself,—so sae
for its imperfections,—so much for the conditions to be
observed in interpreting it, and its chronological indi-
cations, the moment we pass beyond the limits of a
vertical linear section.

Now let us pass from the record to that which it
contains,—from the book itself to the writing and the
figures on its pages. This writing and these figures
consist of remains of animals and plants which, in the

OF ORGANIC NATURE. 43

great majority of cases, have lived and died in the very
spot in which we now find them, or at least in the
immediate vicinity. You must all of you be aware—
and I referred to the fact in last Monday’s lecture—
that there are vast numbers of creatures living at the
bottom of the sea. These creatures, like all others,
sooner or later die, and their shells and hard parts lie
at the bottom; and then the fine mud which is being
constantly brought down by rivers and the action of
the wear and tear of the sea, covers them over and pro-
tects them from any further change or alteration ; and,
of course, as in process of time the mud becomes har-
dened and solidified, the shells of these animals are
preserved and firmly embedded in the limestone or
sandstone which is being thus formed. You may see
in the galleries of the Museum upstairs specimens of
limestones in which such fossil remains of existing
animals are embedded. There are some specimens in
which turtles’ eggs have been imbedded in calcareous
sand, and before the sun had hatched the young turtles,
they became covered over with calcareous mud, and
thus have been preserved and fossilized.

. Not only does this process of imbedding and fossiliza-
tion occur with marine and other aquatic animals and
plants, but it affects those land animals and plants
which are drifted away to sea, or become buried in
bogs or morasses; and the animals which have been
trodden down by their fellows and crushed in the
mud at the river's bank, as the herd have come to
drink. In any of these cases, the organisms may be
crushed or be mutilated, before or after putrefaction,
in such a manner that perhaps only a part will be left

4A THE PAST CONDITION

in the form in which it reaches us. It is, indeed, a
most remarkable fact, that it is quite an exceptional case
to find a skeleton of any one of all the thousands of
wild land animals that we know are constantly being
killed, or dying in the course of nature: they are
preyed on and devoured by other animals, or die in
places where their bodies are not afterwards protected by
mud. There are other animals existing in the sea, the
shells of which form exceedingly large deposits. You
are probably aware that before the attempt was made
to lay the Atlantic telegraphic cable, the Government
employed vessels in making a series of very careful ob-
servations and soundings of the bottom of the Atlantic ;
and although, as we must all regret, that up to the
present time that project has not succeeded, we have
the satisfaction of knowing that it yielded some most
remarkable results to science. The Atlantic Ocean
had to be sounded right across, to depths of several
miles in some places, and the nature of its bottom
was carefully ascertained. Well, now, a space of about
1,000 miles wide from east to west, and I do not
exactly know how many from north to south, but
at any rate 600 or 700 miles, was carefully examined,
and it was found that over the whole of that immense
area an excessively fine chalky mud is being deposited ;
and this deposit is entirely made up of animals whose
hard parts are deposited in this part of the ocean, and
are doubtless gradually acquiring solidity and becoming
metamorphosed into a chalky limestone. Thus, you
see, 1t is quite possible in this way to preserve unmis-
takable records of animal and vegetable life. When-
ever the sea-bottom, by some of those undulations of

OF ORGANIC NATURE. 45

the earth’s crust that I have referred to, becomes up-
heaved, and sections or borings are made, or pits are
dug, then we become able to examine the contents and
constituents of these ancient sea-bottoms, and find out
what manner of animals lived at that period.

Now it is a very important consideration in its
bearing on the completeness of the record, to inquire
how far the remains contained in these fossiliferous lime-
stones are able to convey anything like an accurate
or complete account of the animals which were in
existence at the time of its formation. Upon that
point we can form a very clear judgment, and one in
which there is no possible room for any mistake.
There are of course a great number of animals—such
as jelly-fishes, and other animals—without any hard
parts, of which we cannot reasonably expect to find any
traces whatever: there is nothing of them to preserve-
Within a very short time, you will have noticed, after
they are removed from the water, they dry up to a
mere nothing; certainly they are not of a nature to
leave any very visible traces of their existence on such
bodies as chalk or mud. Then again, look at land
animals; itis, as I have said, a very uncommon thing
to find a land animal entire after death. Insects and
other carnivorous animals very speedily pull them to
pieces, putrefaction takes place, and so, out of the hun-
dreds of thousands that are known to die every year,
it is the rarest thing in the world to see one imbedded
in such a way that its remains would be preserved for a
lengthened period. Not only is this the case, but even
when animal remains have been safely imbedded, certain
natural agents may wholly destroy and remove them.

A6 - THE PAST CONDITION

Almost all the hard parts of animals—the bones and
so on—are composed chiefly of phosphate of lime and
carbonate of lime. Some years ago, I had to make an
inquiry into the nature of some very curious fossils
sent to me from the North of Scotland. Fossils are
usually hard bony structures that have become imbed-
ded in the way I have described, and have gradually
acquired the nature and solidity of the body with
which they are associated; but in this case I had a
series of holes in some pieces of rock, and nothing else.
Those holes, however, had a certain definite shape
about them, and when I got a skilful workman to make
castings of the interior of these holes, I found that
they were the impressions of the joints of a back-
bone and of the armour of a great reptile, twelve or
more feet long. This great beast had died and got
buried in the sand, the sand had gradually hardened
over the bones, but remained porous. Water had
trickled through it, and that water being probably
charged with a superfluity of carbonic acid, had dis-
solved all the phosphate and carbonate of lime, and the
bones themselves had thus decayed and entirely dis-
appeared ; but as the sandstone happened to have con-
solidated by that time, the precise shape of the bones
was retained. If that sandstone had remained soft a
little longer, we should have known nothing whatsoever
of the existence of the reptile whose bones it had
encased.

How certain it is that a vast number of animals which
have existed at one period on this earth have entirely
perished, and left no trace whatever of their forms, may
be proved to you by other considerations. There are

OF ORGANIC NATURE. A.7

large tracts of sandstone in various parts of the world,
in which nobody has yet found anything but footsteps.
Not a bone of any description, but an enormous num-
ber of traces of footsteps. There is no question about
them. There is a whole valley in Connecticut covered
‘with these footsteps, and not a single fragment of
the animals which made them have yet been found.
Let me mention another case while upon that matter,
which is even more surprising than those to which
I have yet referred. There is a limestone formation
near Oxford, at a place called Stonesfield, which has
yielded the remains of certain very interesting mam-
malian animals, and up to this time, if I recollect
rightly, there have been found seven specimens of
its lower jaws, and not a bit of anything else,
neither limb-bones nor skull, or any part whatever;
not a fragment of the whole system! Of course, it
would be preposterous to imagine that the beasts had
nothing else but a lower jaw! The probability is, as
Dr. Buckland showed, as the result of his observations
on dead dogs in the river Thames, that the lower jaw,
not being secured by very firm ligaments to the bones
of the head, and being a weighty affair, would easily
be knocked off, or might drop away from the body
as it floated in water in a state of decomposition. The
jaw would thus be deposited immediately, while the
rest of the body would float and drift away altogether,
ultimately reaching the sea, and perhaps becoming
destroyed. The jaw becomes covered up and preserved
in the river silt, and thus it comes that we have such a
curious circumstance as that of the lower jaws in the
Stonesfield slates. So that, you see, faulty as these

48 THE PAST CONDITION

layers of stone in the earth’s crust are, defective as
they necessarily are as a record, the account of con-
temporaneous vital phenomena presented by them is, by
the necessity of the case, infinitely more defective and
fragmentary.

It was necessary that I should put all this very
strongly before you, because, otherwise, you might
have been led to think differently of the completeness
of our knowledge by the next facts I shall state to you.

The researches of the last three-quarters of a cen-
tury have, in truth, revealed a wonderful richness of
organic life in those rocks. Certainly not fewer than
thirty or forty thousand different species of fossils have
been discovered. You have no more ground for doubt-
ing that these creatures really lived and died at or
near the places in which we find them than you have
for like scepticism about a shell on the sea-shore.
The evidence is as good in the one case as in the
other.

Our next business is to look at the general character
of these fossil remains, and it is a subject which will be
requisite to consider carefully ; and the first point for
us is to examine how much the extinct Flora and Fauna
as a whole—disregarding altogether the succession of
their constituents, of which I shall speak afterwards—
differ from the Flora and Fauna of the present day ;—
how far they differ in what we do know about them,
leaving altogether out of consideration speculations
based on what we do not know.

I strongly imagine that if it were not for the pe-
euliar appearance that fossilized animals have, that
any of you might readily walk through a museum

OF ORGANIC NATURE. 49

which contains fossil remains mixed up with those
of the present forms of life, and I doubt very
much whether your uninstructed eyes would lead
you to see any vast or wonderful difference be-
tween the two. If you looked closely, you would
notice, in the first place, a great many things very
like animals with which you are acquainted now:
you would see differences of shape and proportion,
but on the whole a close similarity.

I explained what I meant by Orprrs the other
day, when I described the animal kingdom as being
divided in sub-kingdoms, classes, and orders. If
you divide the animal kingdom into orders, you
will find that there are above one hundred and
twenty. The number may vary on one side cr the
other, but this is a fair estimate. That is the sum
total of the orders of all the animals which we know
now, and which have been known in past times, and
left remains behind.

Now, how many of those are absolutely extinct ?
That is to say, how many of these orders of ani-
mals have lived at a former period of the world’s
history, but have at present no representatives ?
That is the sense in which I meant to use the word
“extinct.” I mean that those animals did live on
this earth at one time, but have left no one of their
kind with us at the present moment. So that esti-
mating the number of extinct animals is a sort of
way of comparing the past creation as a whole with
the present as a whole. To make that clear, I have
written in red ink on these diagrams the names of all
those extinct orders, and in black ink the names of

50 THE PAST CONDITION

the rest. Among the mammalia and birds there are
none extinct; but when we come to the reptiles there
is a most wonderful thing: out of the eight orders, or
thereabouts, which you can make among reptiles, one-
half are extinct. These diagrams of the plesiosaurus,
the ichthyosaurus, the pterodactyle, give you a notion of
some of these extinct reptiles. And here is a cast of the
pterodactyle and bones of the ichthyosaurus and the
plesiosaurus, just as fresh asif it had been recently dug
up in a churchyard. Thus, in the reptile class, there
are no less than half of the orders which are absolutely
extinct. If we turn to the Amphibia, there was one
extinct order, the Labyrinthodonts, typified by the
large salamander-like beast shown in this diagram.

No order of fishes is known to be extinct. Every
fish that we find in the strata—to which I have been
referring—can be identified and placed in one of the
orders which exist at the present day. There is not
known to be a single ordinal form of insect extinct.
There are only two orders extinct among the Crustacea.
There is not known to be an extinct order of these
creatures, the parasitic and other worms; but there
are two, not to say three, absolutely extinct orders of
this class, the Echinodermata; out of all the orders of
the Ceienterata and Protozoa only one, the Rugose
Corals.

So that, you see, out of somewhere about 120 orders
of animals, taking them altogether, you will not, at
the outside estimate, find above ten or a dozen extinct.
Summing up all the order of animals which have left
remains behind them, you will not find above ten or
a dozen which cannot be arranged with those of the

OF ORGANIC NATURE. oil

present day; that is to say, that the difference does
not amount to much more than ten per cent.: and the
proportion of extinct orders of plants is still smaller.
I think that that is a very astounding, a most astonish-
ing fact, seeing the enormous epochs of time which
have elapsed during the constitution of the surface of
the earth as it at present exists; it is, indeed, a most
astounding thing that the proportion of extinct ordinal
types should be so exceedingly small.

But now, there is another point of view in which we
must look at this past creation. Suppose that we
were to sink a vertical pit through the floor beneath
us, and that I could succeed in making a section
right through in the direction of New Zealand, I
should find in each of the different beds through
which I passed the remains of animals which I should
find in that stratum and not in the others. First, I
should come upon beds of gravel or drift containing
the bones of large animals, such as the elephant,
rhinoceros, and cave tiger. Rather curious things to
fall across in Piccadilly! If I should dig lower
still, I should come upon a bed of what we call the
London clay, and in this, as you will see in our galleries
up-stairs, are found remains of strange cattle, remains
of turtles, palms, and large tropical fruits; with shell-
fish such as you see the like of now only in tropical
regions. If I went below that, I should come upon the
chalk, and there I should find something altogether
different, the remains of ichthyosauri and pterodactyles,
and ammonites, and so forth.

I do not know what Mr. Godwin Austin would say
comes next, but probably rocks containing more ammo-

52 THE PAST CONDITIGN OF ORGANIC NATURE.

nites, and more ichthyosauri and plesiosauri, with a
vast number of other things; and under that I should
meet with yet older rocks, containing numbers of
strange shells and fishes; and in thus passing from
the surface to the lowest depths of the earth’s crust,
the forms of animal life and vegetable life which I
should meet with in the successive beds would, looking
at them broadly, be the more different the further
that I went down. Or, in other words, inasmuch
as we started with the clear principle, that in a series
of naturally-disposed mud beds the lowest are the
oldest, we should come to this result, that the further
we go back in time the more difference exists between
the animal and vegetable life of an epoch and that
which now exists. That was the conclusion to which
{ wished to bring you at the end of this Lecture.

LECTURE III.

THE METHOD BY WHICH THE CAUSES OF
THE PRESENT AND PAST CONDITIONS
OF ORGANIC NATURE ARE TO BE
DISCOVERED. —THE ORIGINATION OF
LIVING BEINGS.

In the two preceding lectures I have endeavoured
to indicate to you the extent of the subject-matter of
the inquiry upon which we are engaged; and now,
having thus acquired some conception of the Past and
Present phenomena of Organic Nature, I must turn,
to-night, to that which constitutes the great problem
which we have set before ourselves ;—I mean, the ques-
tion of what knowledge we have of the causes of these
phenomena of organic nature, and how such knowledge
is obtainable.

Here, on the threshold of the inquiry, an objection
meets us. There are in the world a number of
extremely worthy, well-meaning persons, whose judg-
ments and opinions are entitled to the utmost respect
on account of their sincerity, who are of opinion that
Vital Phenomena, and especially all questions relating
to the origin of vital phenomena, are questions quite

D

5A METHOD OF DISCOVERY.

apart from the ordinary run of inquiry, and are,
by their very nature, placed out of our reach. They
say that all these phenomena originated miraculously,
or in some way totally different from the ordinary
course of nature, and that therefore they conceive it
to be futile, not to say presumptuous, to attempt to
inquire into them.

To such sincere and earnest persons, I would only
say, that a question of this kind is not to be shelved
upon theoretical or speculative grounds. You may re-
member the story of the Sophist who demonstrated to
Diogenes in the most complete and satisfactory manner
that he could not walk; that, in fact, all motion was
an impossibility; and that Diogenes refuted him by
simply getting up and walking round his tub. So, in
the same way, the man of science replies to objections
of this kind, by simply getting up and walking onward,
and showing what science has done and is doing,—by
pointing to that immense mass of facts which have
been ascertained and systematized under the forms of
the great doctrines of Morphology, of Development, of
Distribution, and the like. He sees an enormous mass
of facts and laws relating to organic beings, which
stand on the same good sound foundation as every
other natural law; and, therefore, with this mass of
facts and laws before us, seeing that, as far as organic
matters have hitherto been accessible and studied, they
have shown themselves capable of yielding to scientific
investigation, we may accept this as proof that order
and law reign there as well as in the rest of nature ;
and the man of science says nothing to objectors of

METHOD OF DISCOVERY. 5d

this sort, but supposes that we can and shall walk to
the origin of organic nature, in the same way that we
have walked to a knowledge of the laws and principles
of the inorganic world.

But there are objectors who say the same from
ignorance and ill-will. To such I would reply that the
objection comes ill from them, and that the real pre-
sumption, I may almost say the real blasphemy, in this
matter, is in the attempt to limit that inquiry into the
causes of phenomena which is the source of all human
blessings, and from which has sprung all human pros-
perity and progress; for, after all, we can accomplish
comparatively little ; the limited range of our own facul-
ties bounds us on every side,—the field of our powers
of observation is small enough, and he who endeavours
to narrow the sphere of our inquiries is only pursuing
a course that is likely to produce the greatest harm to
his fellow-men.

But now, assuming, as we all do, I hope, that these-
phenomena are properly accessible to inquiry, and set-
ting out upon our search into the causes of the pheno-
mena of organic nature, or, at any rate, setting out to
discover how much we at present know upon these
abstruse matters, the question arises as to what is to
be our course of proceeding, and what method we must
lay down for our guidance. I reply to that question,
that our method must be exactly the same as that
which is pursued in any other scientific inquiry, the
method of scientific investigation being the same for
all orders: of facts and phenomena whatsoever.

I must dwell a little on this point, for I wish you to.

D2

56 METHOD OF DISCOVERY.

leave this room with a very clear conviction that scien-
tific investigation is not, as many people seem to sup-
pose, some kind of modern black art. I say that you
might easily gather this impression from the manner in
which many persons speak of scientific inquiry, or talk
about inductive and deductive philosophy, or the
principles of the “‘ Baconian philosophy.” I do protest
that, of the vast number of cants in this world, there
are none, to my mind, so contemptible as the pseudo-
scientific cant which is talked about the “ Baconian
philosophy.”

To hear people talk about the great Chancellor,—
and a very great man he certainly was,—you would
think that it was he who had invented science, and
that there was no such thing as sound reasoning
before the time of Queen Elizabeth! Of course,
you say, that cannot possibly be true; you per-
ceive, on a moment’s reflection, that such an idea is
absurdly wrong; and yet, so firmly rooted is this
sort of impression,—I cannot call it an idea, or con-
ception,—the thing is too absurd to be entertained,—
but so completely does it exist at the bottom of most
men’s minds, that this has been a matter of observation
with me for many years past. There are many men
who, though knowing absolutely nothing of the subject
with which they may be dealing, wish, nevertheless, to
damage the author of some view with which they think
fit to disagree. What they do, then, is not to go and
learn something about the subject, which one would
naturally think the best way of fairly dealing with it;
but they abuse the originator of the view they question,

METHOD OF DISCOVERY. 57

in a general manner, and wind up by saying that,
“ After all, you know, the principles and method of
this author are totally opposed to the canons of the
Baconian philosophy.” Then everybody applauds, as
a matter of course, and agrees that it must be
so. But if you were to stop them all in the middle
of their applause, you would probably find that
neither the speaker nor his applauders could tell you
how or in what way it was so; neither the one nor
the other having the slightest idea of what they mean
when they speak of the “‘ Baconian philosophy.”

You will understand, I hope, that I have not the
slightest desire to join in the outcry against either
the morals, the intellect, or the great genius of Lord
Chancellor Bacon. He was undoubtedly a very great
man, let people say what they will of him; but’ not-
withstanding all that he did for philosophy, it would
be entirely wrong to suppose that the methods of
modern scientific inquiry originated with him, or with
his age; they originated with the first man, whoever
he was; and indeed existed long before him, for many
of the essential processes of reasoning are exerted by
the higher order of brutes as completely and effectively
as by ourselves. We see in many of the brute creation
the exercise of one, at least, of the same powers of
reasoning as that which we ourselves employ.

The method of scientific investigation is nothing but
the expression of the necessary mode of working of the
human mind. It is simply the mode at which all phe-
nomena are reasoned about, rendered precise and exact.
There is no more difference, but there is just the same

58 METHOD OF DISCOVERY.

kind of difference, between the mental operations of a
man of science and those of an ordinary person, as
there is between the operations and methods of a baker
or of a butcher weighing out his goods in common,
scales, and the operations of a chemist in performing
a difficult and complex analysis by means of his balance
and finely-graduated weights. It is not that the action
of the scales in the one case, and the balance in the
other, differ in the principles of their construction or
manner of working; but the beam of one is set on an
infinitely finer axis than the other, and of course turns:
by the addition of a much smaller weight.

You will understand this better, perhaps, if I give:
you some familiar example. You have all heard it re-
peated, I dare say, that men of science work by means
of Induction and Deduction, and that by the help of
these operations, they, in a sort of sense, wring from
Nature certain other things, which are called Natural
Laws, and Causes, and that out of these, by some
cunning skill of their own, they build up Hypotheses
and Theories. And it is imagined by many, that the
operations of the common mind can be by no means
compared with these processes, and that they have to be:
acquired by a sort of special apprenticeship to the
craft. To hear all these large words, you would think
that the mind of a man of science must be constituted
differently from that of his fellow men; but if you will
not be frightened by terms, you will discover that you
are quite wrong, and that all these terrible apparatus
are being used by yourselves every day and every hour
of your lives..

9

or

METHOD OF DISCOVERY.

‘There is a well-known incident in one of Moliére’s
plays, where the author makes the hero express
unbounded delight on being told that he had been
talking prose during the whole of his life. In the
same way, I trust, that you will take comfort, and
be delighted with yourselves, on the discovery that
you have been acting on the principles of induc-
tive aud deductive philosophy during the same period.
Probably there is not one here to-night who has not
im the course of the day had occasion to set in motion
a complex train of reasoning, of the very same kind,
though differing of course in degree, as that which a
scientific man goes through in tracing the causes of
natural phenomena.

A very trivial circumstance will serve to exemplify
this. Suppose you go into a fruiterer’s shop, wanting
an apple,—you take up one, and, on biting it, you find
it is sour; you look at it, and see that it is hard and
green. You take up another one, and that too is hard,
green, and sour. The shopman offers you a third; but,
before biting it, you examine it, and find that it is
hard and green, and you immediately say that you will
not have it, as it must be sour, like those that you have
already tried.

Nothing can be more simple than that, you think;
but if you will take the trouble to analyze and trace
out ito its logical elements what has been done by
the mind, you will be greatly surprised. In the first
place, you have performed the operation of Induc-
tion. You found that, in two experiences, hardness
and greenness in apples go together with sourness.

60 METHOD OF DISCOVERY.

It was so in the first case, and it was confirmed by
the second. True, it is a very small basis, but still it is.
enough to make an induction from; you generalize the
facts, and you expect to find sourness in apples where
you get hardness and greenness. You found upon
that a general law, that all hard and green apples are
sour; and that, so far as it goes, is a perfect induction.
Well, having got your natural law in this way, when
you are offered another apple which you find is hard
and green, you say, “ All hard and green apples are
sour; this apple is hard and green, therefore this
apple is sour.” That train of reasoning is what logi-
cians call a syllogism, and has all its various parts and
terms,—its major premiss, its minor premiss, and its
conclusion. And, by the help of further reasoning,
which, if drawn out, would have to be exhibited in two
or three other syllogisms, you arrive at your final
determination, “I will not have that apple.” So that,
you see, you have, in the first place, established a law
by Induction, and upon that you have founded a
Deduction, and reasoned out the special conclusion
of the particular case. Well now, suppose, having
got your law, that at some time afterwards, you are
discussing the qualities of apples with a friend: you
will say to him, “It is a very curious thing,—but I
find that all hard and green apples are sour!” Your
friend says to you, “ But how do you know that?”
You at once reply, “ Oh, because I have tried it over
and over again, and have always found them to be so.”
Well, if we were talking science instead of common
sense, we should call that an Experimental Verification.

METHOD OF DISCOVERY. 61

And, if still opposed, you go further, and say, “I have
heard from the people in Somersetshire and Devon-
shire, where a large number of apples are grown, that
they have observed the same thing. It is also found
to be the case in Normandy, and in North America.
In short, I find it to be the universal experience of
mankind wherever attention has been directed to the
subject.” Whereupon, your friend, unless he is a
very unreasonable man, agrees with you, and is con-
vinced that you are quite right in the conclusion you
have drawn. He believes, although perhaps he does
not know he believes it, that the more extensive Veri-
fications are, —that the more frequently experiments
have been made, and results of the same kind arrived
at,—that the more varied the conditions under which
the same results have been attained, the more certain
is the ultimate conclusion, and he disputes the ques-
tion no further. He sees that the experiment has been
tried under all sorts of conditions, as to time, place,
and people, with the same result; and he says with
you, therefore, that the law you have laid down must
‘be a good one, and he must believe it.

In science we do the same thing ;—the philosopher
exercises precisely the same faculties, though in a much
more delicate manner. In scientific inquiry it becomes
a matter of duty to expose a supposed law to every
possible kind of verification, and to take care, more-
over, that this is done intentionally, and not left to a
mere accident, as in the case of the apples. And
in science, as in common life, our confidence in a
daw is in exact proportion to the absence of varia-

62 METHOD OF DISCOVERY.

tion in the result of our experimental verifica-
tions. For instance, if you let go your grasp of an
article you may have in your hand, it will imme-
diately fall to the ground. That is a very common
verification of one of the best established laws of
nature—that of gravitation. The method by which
men of science establish the existence of that law is
exactly the same as that by which we have estab-
lished the trivial proposition about the sourness of
hard and green apples. But we believe it in such an
extensive, thorough, and unhesitating manner because
the universal experience of mankind verifies it, and we
can verify it ourselves at any time; and that is the
strongest possible foundation on which any natural law
can rest.

So much by way of proof that the method of esta-
blishing laws in science is exactly the same as that
pursued in common life. Let us now turn to another
matter (though really it is but another phase of the
same question), and that is, the method by which, from
the relations of certain phenomena, we prove that some >
stand in the position of causes towards the others.

I want to put the case clearly before you, and I will
therefore show you what I mean by another familiar
example. I will suppose that one of you, on coming
down in the morning to the parlour of your house,
finds that a tea-pot and some spoons which had been
left in the room on the previous evening are gone,
—the window is open, and you observe the mark of a
dirty hand on the window-frame, and perhaps, in addi-
tion to that, you notice the impress of a hob-nailed.

METHOD OF DISCOVERY. 63

shoe on the gravel outside. All these phenomena have
struck your attention instantly, and before two minutes
have passed you say, “Oh, somebody has broken open
the window, entered the room, and run off with the
spoons and the tea-pot!” That speech is out of your
mouth ina moment. And you will probably add, “I
know there has; I am quite sure of it!” You mean
to say exactly what you know; but in reality what
you have said has been the expression of what is,
in all essential particulars, a Hypothesis. You do
not know it at all; it is nothing but a hypothesis
rapidly framed in your own mind! And it is a
hypothesis founded on a long train of inductions and
deductions.

What are those inductions and deductions, and how
have you got at this hypothesis? You have observed,
in the first place, that the window is open; but by a
train of reasoning involving many Inductions and
Deductions, you have probably arrived long before
at the General Law—and a very good one it is—
that windows do not open of themselves; and you
therefore conclude that something has opened the
window. A second general law that you have arrived
at in the same way is, that tea-pots and spoons do not
go out of a window spontaneously, and you are satisfied
that, as they are not now where you left them,
‘they have been removed. In the third place, you look
at the marks on the window-sill, and the shoe-marks
outside, and you say that in all previous experience
the former kind of mark has never been produced by
anything else but the hand of ahuman being ; and the

64: METHOD OF DISCOVERY.

same experience shows that no other animal but man:
at present wears shoes with hob-nails on them such
as would produce the marks in the gravel. I do not
know, even if we could discover any of those “ missing
links” that are talked about, that they would help
us to any other conclusion! At any rate the law
which states our present experience is strong enough
for my present purpose. You next reach the con-
clusion, that as these kinds of. marks have not
been left by any other animals than men, or are
liable to be formed in any other way than by a man’s
hand and shoe, the marks in question have been
formed by a man in that way. You have, further, a
general law, founded on observation and experience,
and that, too, is, I am sorry to say, a very universal
and unimpeachable one,—that some men are thieves;
and you assume at once from all these premisses—and
that is what constitutes your hypothesis—that the
man who made the marks outside and on the window-
sill, opened the window, got into the room, and
stole your tea-pot and spoons. You have now arrived
at a Vera Causa ;—you have assumed a Cause which
it is plain is competent to produce all the phenomena
you have observed. You can explain all these pheno-
mena only by the hypothesis of a thief. But that is
a hypothetical conclusion, of the justice of which you:
haye no absolute proof at all; it is only rendered
highly probable by a series of inductive and deductive
reasonings.

I suppose your first action, assuming you are a
man of ordinary common sense, and that you have:

METHOD OF DISCOVERY, 65

established this hypothesis to your own satisfaction,
will very likely be to go off for the police, and set
them on the track of the burglar, with the view to the
recovery of your property. But just as you are starting
with this object, some person comes in, and on learning
what you are about, says, “ My good friend, you are
going on a great deal too fast. How do you know that
the man who really made the marks took the spoons?
It might have been a monkey that took them, and the
man may have merely looked in afterwards.” You
would probably reply, “ Well, that is all very well,
but you see it is contrary to all experience of the way
tea-pots and spoons are abstracted; so that, at any
rate, your hypothesis is less probable than mine.”
While you are talking the thing over in this way,
another friend arrives, one of that good kind of people
that I was talking of a little while ago. And he might
say, “Oh, my dear sir, you are certainly going on a
great deal too fast. You are most presumptuous. You
admit that all these occurrences took place when you
were fast asleep, at a time when you could not possibly
have known anything about what was taking place.
How do you know that the laws of Nature are not
suspended during the night? It may be that there has
been some kind of supernatural interference in this
case.” In point of fact, he declares that your hypothesis
is one of which you cannot at all demonstrate the
truth, and that you are by no means sure that the
laws of Nature are the same when you are asleep as
when you are awake.

Well, now, you cannot at the moment answer that

66 METHOD OF DISCOVERY.

kind of reasoning. You feel that your worthy friend .
has you somewhat at a disadvantage. You will feel
perfectly convinced in your own mind, however, that
you are quite right, and you say to him, “My good
friend, I can only be guided by the natural probabilities
of the case, and if you will be kind enough to stand
aside and permit me to pass, I will go and fetch the
police.” Well, we will suppose that your journey is
successful, and that by good luck you meet with a
policeman ; that eventually the burglar is found with
your property on his person, and the marks correspond
to his hand and to his boots. Probably any jury would
consider those facts a very good experimental verifica-
tion of your hypothesis, touching the cause of the
abnormal phenomena observed in your parlour, and
would act accordingly.

Now, in this supposititious case, I have taken
phenomena of a very common kind, in order that
you might see what are the different steps in an
ordinary process of reasoning, if you will only
take the trouble to analyze it carefully. All the
operations I have described, you will see, are in-
volved in the mind of any man of sense in leading
him to a conclusion as to the course he should take
in order to make good a robbery and punish the
offender. I say that you are led, in that case, to
your conclusion by exactly the same train of reason-
ing as that which a man of science pursues when
he is endeavouring to discover the origin and laws
of the most occult phenomena. The process is,
and always must be, the same; and precisely the

METHOD OF DISCOVERY. 67

same mode of reasoning was employed by Newton
and Laplace in their endeavours to discover and de-
fine the causes of the movements of the heavenly
bodies, as you, with your own common sense, would
employ to detect a burglar. The only difference is,
that the nature of the inquiry being more abstruse,
every step has to be most carefully watched, so that
there may not be a single crack or flaw in your
hypothesis. A flaw or crack in many of the hy-
potheses of daily life may be of little or no moment
as affecting the general correctness of the conclusions
at which we may arrive; but in a scientific inquiry
a fallacy, great or small, is always of importance, and
is sure to be constantly productive of mischievous, if
not fatal, results in the long run.

Do not allow yourselves to be misled by the common
notion that a hypothesis is untrustworthy simply
because it is a hypothesis. It is often urged, in respect
to some scientific conclusion, that, after all, it is only
a hypothesis. But what more have we to guide us in
nine-tenths of the most important affairs of daily life
than hypotheses, and often very ill-based ones? So that
in science, where the evidence of a hypothesis is subjected
to the most rigid examination, we may rightly pursue
the same course. You may have hypotheses and hy-
potheses. A man may say, if he likes, that the moon
is made of green cheese: that is a hypothesis. But
another man, who has devoted a great deal of time
and attention to the subject, and availed himself of
the most powerful telescopes and the results of the
observations of others, declares that in his opinion it is

68 METHOD OF DISCOVERY.

probably composed of materials very similar to those of
which our own earth is made up: and that is also only a
hypothesis. But I need not tell you that there is an
enormous difference in the value of the two hypotheses.
That one which is based on sound scientific knowledge
is sure to have a corresponding value; and that which
is a mere hasty random guess is likely to have but
little value. Every great step in our progress in dis-
covering causes has been made in exactly the same
way as that which I have detailed to you. A person
observing the occurrence of certain facts and pheno-
mena asks, naturally enough, what process, what kind
of operation known to occur in nature applied to the
particular case, will unravel and explain the mystery?
Hence you have the scientific hypothesis; and its value
will be proportionate to the care and completeness with
which its basis had been tested and verified. It is
in these matters as in the commonest affairs of prac-
tical life: the guess of the fool will be folly, while
the guess of the wise man will contain wisdom. In
all cases, you see that the value of the result depends
on the patience and faithfulness with which the in-
vestigator applies to his hypothesis every possible kind
of verification.

I dare say I may have to return to this point by-
and-by; but having dealt thus far with our logical
methods, I must now turn to something which, per-
haps, you may consider more interesting, or, at any
rate, more tangible. But in reality there are but few
things that can be more important for you to under-
stand than the mental processes and the means by

ORIGINATION OF LIVING BEINGS. 69

which we obtain scientific conclusions and theories.*
Having granted that the inquiry is a proper one, and
having determined on the nature of the methods we
are to pursue and which only can lead to success, I
must now turn to the consideration of our knowledge
of the nature of the processes which have resulted in
the present condition of organic nature.

Here, let me say at once, lest some of you misunder-
stand me, that I have extremely little to report. The
question of how the present condition of organic nature
came about, resolves itself into two questions. The first
is: How has organic or living matter commenced its
existence? And the second is: How has it been per-
petuated? On the second question I shall have more
to say hereafter. But on the first one, what I now
have to say will be for the most part of a negative
character.

If you consider what kind of evidence we can have
upon this matter, it will resolve itself into two kinds.
We may have historical evidence and we may have
experimental evidence. It is, for example, conceivable,
that inasmuch as the hardened mud which forms a
considerable portion of the thickness of the earth’s
crust contains faithful records of the past forms of
life, and inasmuch as these differ more and more
as we go further down,—it is possible and conceiv-
able that we might come to some particular bed
or stratum which should contain the remains of those

* Those who wish to study fully the doctrines of which I have
endeavoured to give some rough and ready illustrations, must read
Mr, John Stuart Mill’s “ System of Logic.”

70 ORIGINATION OF LIVING BEINGS.

creatures with which organic life began upon the
earth. And if we did so, and if such forms of organic
life were preservable, we should have what I would call
historical evidence of the mode in which organic life
began upon this planet. Many persons will tell you,
and indeed you will find it stated in many works on
geology, that this has been done, and that we really
possess such a record; there are some who imagine
that the earliest forms of life of which we have as yet
discovered any record, are in truth the forms in which
animal life began upon the globe. The grounds on
which they base that supposition are these:—That if
you go through the enormous thickness of the earth’s
crust and get down to the older rocks, the higher
vertebrate animals—the quadrupeds, birds, and fishes—
cease to be found; beneath them you find only the in-
vertebrate animals; and in the deepest and lowest rocks
those remains become scantier and scantier, not in any
very gradual progression, however, until, at length, in
what are supposed to be the oldest rocks, the animal
remains which are found are almost always confined to
four forms, — Oldhamia, whose precise nature is not
known, whether plant or animal; Lingula, a kind of
mollusc; Trilobites, a crustacean animal, having the
same essential plan of construction, though differing in
many details from a lobster or crab ; and Hymenocaris,
which is also a crustacean. So that you have all the
Fauna reduced, at this period, to four forms: one a
kind of animal or plant that we know nothing about,
and three undoubted animals—two crustaceans and
one mollusc.

ORIGINATION OF LIVING BEINGS. 71

I think, considering the organization of these mollusca
and crustacea, and looking at their very complex
nature, that it does indeed require a very strong
imagination to conceive that these were the first
created of all living things. And you must take into
consideration the fact that we have not the slightest
proof that these which we call the oldest beds are
really so: I repeat, we have not the slightest proof of
it. When you find in some places that in an enormous
thickness of rocks there are but very scanty traces of
life, or absolutely none at all; and that in other parts of
the world rocks of the very same formation are crowded
with the records of living forms; I think it is impos-
sible to place any reliance on the supposition, or to feel
oneself justified in supposing that these are the forms
in which life first commenced. I have not time here to
enter upon the technical grounds upon which I am led
to this conclusion,—that could hardly be done properly
in half a dozen lectures on that part alone;—I must
content myself with saying that I do not at all believe
that these are the oldest forms of life.

I turn to the experimental side to see what evidence
we have there. To enable us to say that we know
anything about the experimental origination of organ-
ization and life, the investigator ought to be able to
take inorganic matters, such as carbonic acid, ammonia,
water, and salines, in any sort of inorganic combina-
tion, and be able to build them up into Protein matter,
and that that Protein matter ought to begin to live in
an organic form. That, nobody has done as yet, and
I suspect it will be a long while before anybody does

72 ORIGINATION OF LIVING BEINGS.

doit. But the thing is by no means so impossible as
it looks; for the researches of modern chemistry have
shown us—I won’t say the road towards it, but, if I
may so say, they have shown the finger-post pointing
to the road that may lead to it.

It is not many years ago—and you must recollect
that Organic Chemistry is a young science, not above
a couple of generations old,--you must not expect too
much of it; it is not many years ago since it was said
to be perfectly impossible to fabricate any organic com-
pound ; that is to say, any non-mineral compound which
is to be found in an organized being. It remained so
for a very long period; but it is now a considerable
number of years since a distinguished foreign chemist
contrived to fabricate Urea, a substance of a very
complex character, which forms one of the waste pro-
ducts of animal structures. And of late years a
number of other compounds, such as Butyric Acid,
and others, have been added to the list. I need not
tell you that chemistry is an enormous distance from
the goal I indicate; all I wish to point out to you is,
that it is by no means safe to say that that goal may
not be reached one day. It may be that it is impossible
for us to produce the conditions requisite to the origi-
nation of life; but we must speak modestly about the
matter, and recollect that Science has put her foot
upon the bottom round of the ladder. Truly he would
be a bold man who would venture to predict where
she will be fifty years hence.

There is another inquiry which bears indirectly
upon this question, and upon which I must say a few

ORIGINATION OF LIVING BEINGS. 73

*

words. You are all of you aware of the phenomena
of what is called spontaneous generation. Our fore-
fathers, down to the seventeenth century, or there-
abouts, all imagined, in perfectly good faith, that
certain vegetable and animal forms gave birth, in the
process of their decomposition, to insect life. Thus, if
you put a piece of meat in the sun, and allowed it to
putrefy, they conceived that the grubs which soon
began to appear were the result of the action of a
power of spontaneous generation which the meat con-
tained. And they could give you receipts for making
various animal and vegetable preparations which would
produce particular kinds of animals. A very distin-
guished Italian naturalist, named Redi, took up the
question, at a time when everybody believed in it;
among others our own great Harvey, the discoverer
of the circulation of the blood. You will constantly
find his name quoted, however, as an opponent of the
doctrine of spontaneous generation; but the fact is,
and you will see it if you will take the trouble to look
into his works, Harvey believed it as profoundly as
any man of his time; but he happened to enunciate
a very curious proposition—that every living thing
came from an egg; he did not mean to use the word
in the sense in which we now employ it, he only
meant to say that every living thing originated in a
little rounded particle of organized substance; and it
is from this circumstance, probably, that the notion of
Harvey having opposed the doctrine originated. ‘Then
came Redi, and he proceeded to upset the doctrine in a
very simple manner. He merely covered the piece of

74 ORIGINATION OF LIVING BEINGS.

meat with some very fine gauze, and then he exposed
it to the same conditions. The result of this was that
no grubs or insects were produced; he proved that the
grubs originated from the insects who came and de-
posited their eggs in the meat, and that they were
hatched by the heat of the sun. By this kind of inquiry
he thoroughly upset the doctrine of spontaneous gene-
ration, for his time at least.

Then came the discovery and application of the
microscope to scientific inquiries, which showed to
naturalists that besides the organisms which they
already knew as living beings and plants, there were
an immense number of minute things which could
be obtained apparently almost at will from decaying
vegetable and animal forms. Thus, if you took some
ordinary black pepper or some hay, and steeped it m
water, you would find in the course of a few days that
the water had become impregnated with an immense
number of animalcules swimming about in all directions.
From facts of this kind naturalists were led to revive
the theory of spontaneous generation. They were
headed here by an English naturalist,—Needham,—
and afterwards in France by the learned Buffon. They
said that these things were absolutely begotten in the
water of the decaying substances out of which the
infusion was made. It did not matter whether you took
animal or vegetable matter, you had only to steep it in
water and expose it, and you would soon have plenty
of animalcules. They made a hypothesis about this
which was a very fair one. They said, this matter of
the animal world, or of the higher plants, appears to be

ORIGINATION OF LIVING BEINGS. ri)

dead, but in reality it has a sort of dim life about it,
which, if it is placed under fair conditions, will cause
it to break up into the forms of these little animalcules,
and they will go through their lives in the same way as
the animal or plant of which they once formed a part.

The question now became very hotly debated. Spal-
lanzani, an Italian naturalist, took up opposite views to
those of Needham and Buffon, and by means of certain
experiments he showed that it was quite possible to stop
the process by boiling the water, and closing the vessel
in which it was contained. “Oh!” said his oppo-
nents; “but what do you know you may be doing
when you heat the air over the water in this way?
You may be destroying some property of the air
requisite for the spontaneous generation of the animal-
cules.”

However, Spallanzani’s views were supposed to be
upon the right side, and those of the others fell into
discredit ; although the fact was that Spallanzani had
not made good his views. Well, then, the subject con-
tinued to be revived from time to time, and experi-
ments were made by several persons; but these experi-
ments were not altogether satisfactory. It was found
that if you put an infusion in which animalcules would
appear if it were exposed to the air into a vessel and
boiled it, and then sealed up the mouth of the vessel,
so that no air, save such as had been heated to 212°,
could reach its contents, that then no animalcules would
be found ; but if you took the same vessel and exposed
the infusion to the air, then you would get animalcules.
Furthermore, it was found that if you connected the

76 ORIGINATION OF LIVING BEINGS.

mouth of the vessel with a red-hot tube in such a way
that the air would have to pass through the tube
before reaching the infusion, that then you would get
noanimalcules. Yet another thing was noticed: if you
took two flasks containing the same kind of infusion,
and left one entirely exposed to the air, and in the
mouth of the other placed a ball of cotton wool, so
that the air would have to filter itself through it be-
fore reaching the infusion, that then, although you
might have plenty of animalcules in the first flask,
you would certainly obtain none from the second.

These experiments, you see, all tended towards one
conclusion — that the infusoria were developed from
little minute spores or eggs which were constantly
floating in the atmosphere, which lose their power of
germination if subjected to heat. But one observer
now made another experiment, which seemed to go
entirely the other way, and puzzled him altogether.
He took some of this boiled infusion that I have
been speaking of, and by the use of a mercurial
bath—a kind of trough used in laboratories—he deftly
inverted a vessel containing the infusion into the
mercury, so that the latter reached a little beyond the
level of the mouth of the inverted vessel. You see
that he thus had a quantity of the infusion shut off
from any possible communication with the outer air
by being inverted upon a bed of mercury.

He then prepared some pure oxygen and nitrogen
gases, and passed them by means of a tube going from
the outside of the vessel, up through the mercury into
the infusion; so that he thus had it exposed to a per-

ORIGINATION OF LIVING BEINGS. 77

fectly pure atmosphere of the same constituents as
the external air. Of course, he expected he would
get no infusorial animalcules at all in that infusion ;
but, to his great dismay and discomfiture, he found he
almost always did get them.

Furthermore, it has been found that experiments
made in the manner described above answer well with
most infusions; but that if you fill the vessel with
boiled milk, and then stop the neck with cotton-wool,
you will have infusoria. So that you see there were two
experiments that brought you to one kind of conclusion,
and three to another; which was a most unsatisfactory
state of things to arrive at in a scientific inquiry.

Some few years after this, the question began to be
very hotly discussed in France. There was M. Pouchet,
a professor at Rouen, a very learned man, but certainly
not a very rigid experimentalist. He published a
number of experiments of his own, some of which
were very ingenious, to show that if you went to
work in a proper way, there was a truth in the doc-
trine of spontaneous generation. Well, it was one of
the most fortunate things in the world that M. Pouchet
took up this question, because it induced a distinguished
French chemist, M. Pasteur, to take up the question
on the other side; and he has certainly worked it out
in the most perfect manner. I am glad to say, too,
that he has published his researches in time to enable
me to give you an account of them. He verified all
the experiments which I have just mentioned to you—
and then finding those extraordinary anomalies, as in
the case of the mercury bath and the milk, he set

78 ORIGINATION OF LIVING BEINGS.

himself to work to discover their nature. In the case
of milk he found it to be a question of temperature.
Milk in a fresh state is slightly alkaline; and it is a
very curious circumstance, but this very slight degree
of alkalinity seems to have the effect of preserving the
organisms which fall into it from the air from being
destroyed at a temperature of 212°, which is the boil-
ing point. But if you raise the temperature 10° when
you boil it, the milk behaves like everything else; and
if the air with which it comes in contact, after being
boiled at this temperature, is passed through a red-hot
tube, you will not get a trace of organisms.

He then turned his attention to the mercury bath,
and found on examination that the surface of the mer-
cury was almost always covered with a very fine dust.
He found that even the mercury itself was positively
full of organic matters; that from being constantly
exposed to the air, it had collected an immense number
of these infusorial organisms from the air. Well,
under these circumstances he felt that the case was
quite clear, and that the mercury was not what it had
appeared to M. Schwann to be,—a bar to the admission
of these organisms; but that, in reality, it acted asa
reservoir from which the infusion was immediately sup-
plied with the large quantity that had so puzzled him.

But not content with explaining the experiments of
others, M. Pasteur went to work to satisfy himself
completely. He said to himself: “If my view is right,
and if, in point of fact, all these appearances of spon-
taneous generation are altogether due to the falling of
minute germs suspended in the atmosphere,—why, I

ORIGINATION OF LIVING BEINGS. 79

ought not only to be able to show the germs, but I
ought to be able to catch and sow them, and produce
the resulting organisms.” He, accordingly, constructed
a very ingenious apparatus to enable him to accom-
plish this trapping of this “germ dust” in the air. He
fixed in the window of his room a glass tube, in the
centre of which he had placed a ball of gun-cotton,
which, as you all know, is ordinary cotton-wool,
which, from having been steeped in strong acid, is con-
verted into a substance of great explosive power. It
is also soluble in alcohol and ether. One end of the
glass tube was, of course, open to the external air ; and
at the other end of it he placed an aspirator, a con-
rivance for causing a current of the external air to
pass through the tube. He kept this apparatus going
for four-and-twenty hours, and then removed the
dusted gun-cotton, and dissolved it in alcohol and
ether. He then allowed this to stand for a few
hours, and the result was, that a very fine dust was
gradually deposited at the bottom of it. That dust,
on being transferred to the stage of a microscope,
was found to contain an enormous number of starch
grains. You know that the materials of our food and
the greater portion of plants are composed of starch,
and we are constantly making use of it in a variety of
ways, so that there is always a quantity of it suspended
in the air. It is these starch grains which form
many of those bright specks that we see dancing
in a ray of light sometimes. But besides these,
M. Pasteur found also an immense number of other
organic substances such as spores of fungi, which had

80 ORIGINATION OF LIVING BEINGS.

been floating about in the air and had got caged in
this way.

He went farther, and said to himself, “If these
really are the things that give rise to the appearance
of spontaneous generation, I ought to be able to take
a ball of this dusted gun-cotton and put it into one of
my vessels, containing that boiled infusion which has
been kept away from the air, and in which no in-
fusoria are at present developed, and then, if I am
right, the introduction of this gun-cotton will give rise
to organisms.”

Accordingly, he took one of these vessels of in-
fusion, which had been kept eighteen months, without
the least appearance of life, and by a most ingenious
contrivance, he managed to break it open and in-
troduce such a ball of gun-cotton, without allowing
the infusion or the cotton ball to come into contact
with any air but that which had been subjected to a
red heat, and in twenty-four hours he had the satis-
faction of finding all the indications of what had been
hitherto called spontaneous generation. He had suc-
ceeded in catching the germs and developing organisms
in the way he had anticipated.

It now struck him that the truth of his conclusions
might be demonstrated without all the apparatus he
had employed. To do this, he took some decaying
animal or vegetable substance, such as urine, which
is an extremely decomposable substance, or the juice
of yeast, or perhaps some other artificial preparation,
and filled a vessel having a long tubular neck, with
it. He then boiled the liquid and bent that long neck

ORIGINATION OF LIVING BEINGS. 81

into an S shape or zig-zag, leaving it open at the end.
The infusion then gave no trace of any appearance
of spontaneous generation, however long it might be
left, as all the germs in the air were deposited in the
beginning of the bent neck. He then cut the tube
close to the vessel, and allowed the ordinary air to
have free and direct access; and the result of that
was the appearance of organisms in it, as scon as the
infusion had been allowed to stand long enough to
allow of the growth of those it received from the
air, which was about forty-eight hours. The result
of M. Pasteur’s experiments proved, therefore, in the
most conclusive manner, that all the appearances of
spontaneous generation arose from nothing more than
the deposition of the germs of organisms which were
constantly floating in the air.

To this conclusion, however, the objection was
made, that if that were the cause, then the air
would contain such an enormous number of these
germs, that it would be a continual fog. But M.
Pasteur replied that they are not there in anything
like the number we might suppose, and that an exag-
gerated view has been held on that subject; he showed
that the chances of animal or vegetable life appearing
in infusions, depend entirely on the conditions under
which they are exposed. If they are exposed to the
ordinary atmosphere around us, why, of course, you
may have organisms appearing early. But, on the
other hand, if they are exposed to air from a great
height, or from some very quiet cellar, you will often
not find a single trace of life.

82 ORIGINATION OF LIVING BEINGS.

So that M. Pasteur arrived at last at the clear
and definite result, that all these appearances are
like the case of the worms in the piece of meat, which
was refuted by Redi, simply germs carried by the air
and deposited in the liquids in which they afterwards
appear. For my own part, I conceive that, with the
particulars of M. Pasteur’s experiments before us, we
cannot fail to arrive at his conclusions; and that
the doctrine of spontaneous generation has received
a final coup de grace.

You, of course, understand that all this in no way
interferes with the possibility of the fabrication of
organic matters by the direct method to which I have:
referred, remote as that possibility may be.

PE Cl U Bri BV:

THE PERPETUATION OF LIVING BEINGS,
HEREDITARY TRANSMISSION AND
VARIATION.

THE inquiry which we undertook, at our last meet-
ing, into the state of our knowledge of the causes of the
phenomena of organic nature,—of the past and of the
present,—resolved itself into two subsidiary inquiries :
the first was, whether we know anything, either his-
torically or experimentally, of the mode of origin
of living beings; the second subsidiary inquiry was,
whether, granting the origin, we know anything about
the perpetuation and modifications of the forms of
organic beings. The reply which I had to give to
the first question was altogether negative, and the
chief result of my last lecture was, that, neither his-
torically nor experimentally, do we at present know
anything whatsoever about the origin of living forms.
We saw that, historically, we are not likely to know
anything about it, although we may perhaps learn
something experimentally ; but that at present we are
an enormous distance from the goal I indicated.

I now, then, take up the next question, What do we

84, THE PERPETUATION OF LIVING BEINGS,

know of the reproduction, the perpetuation, and the
modifications of the forms of living beings, supposing
that we have put the question as to their origination
on one side, and have assumed that at present the
causes of their origination are beyond us, and that
we know nothing about them? Upon this question
the state of our knowledge is extremely different; it
is exceedingly large, and, if not complete, our ex-
perience is certainly most extensive. It would be im-
possible to lay it all before you, and the most I can
do, or need do to-night, is to take up the principal
points and put them before you with such prominence as
may subserve the purposes of our present argument.
The method of the perpetuation of organic beings is
of two kinds,—the asexual and the sexual. In the
first the perpetuation takes place from and by a par-
ticular act of an individual organism, which sometimes
may not be classed as belonging to any sex at all.
In the second case, it is in consequence of the mutual
action and interaction of certain portions of the or-
ganisms of usually two distinct individuals,—the male
and the female. The cases of asexual perpetuation
are by no means so common as the cases of sexual
perpetuation ; and they are by no means so common
in the animal as in the vegetable world. You are all
probably familiar with the fact, as a matter of ex-
perience, that you can propagate plants by means of
what are called “ cuttings ;” for example, that by
taking a cutting from a geranium plant, and rearing
it properly, by supplying it with light and warmth
and nourishment from the earth, it grows up and

HEREDITARY TRANSMISSION AND VARIATION. 85

takes the form of its parent, having all the properties
and peculiarities of the original plant.

Sometimes this process, which the gardener performs
artificially, takes place naturally ; that is to say, a little
bulb, or portion of the plant, detaches itself, drops off,
and becomes capable of growing as a separate thing.
That is the case with many bulbous plants, which throw
off in this way secondary bulbs, which are lodged in
the ground and become developed into plants. This
is an asexual process, and from it results the repetition
or reproduction of the form of the original being from
which the bulb proceeds.

Among animals the same thing takes place. Among
the lower forms of animal life, the infusorial animalcule
we have already spoken of throw off certain portions,
or break themselves up in various directions, some-
times transversely or sometimes longitudinally ; or they
may give off buds, which detach themselves and
develop into their proper forms. There is the common
fresh-water Polype, for instance, which multiplies itself
in this way. Just in the same way as the gardener is
able to multiply and reproduce the peculiarities and
characters of particular plants by means of cuttings,
so can the physiological experimentalist,—as was shown
by the Abbé Trembley many years ago,—so can he do
the same thing with many of the lower forms of
animal life. M.de Trembley showed that you could
take a polype and cut it into two, or four, or many
pieces, mutilating it in all directions, and the pieces
would still grow up and reproduce completely the
original form of the animal. These are all cases of

86 THE PERPETUATION OF LIVING BEINGS,

asexual multiplication, and there are other instances,
and still more extraordinary ones, in which this pro-
cess takes place naturally, in a more hidden, a more
recondite kind of way. You are all of you familiar
with those little green insects, the Aphis or blight,
as it is called. These little animals, during a very
considerable part of their existence, multiply them-
selves by means of a kind of internal budding, the
buds being developed into essentially asexual animals,
which are neither male nor female; they become
converted into young Aphides, which repeat the
process, and their offspring after them, and so on
again; you may go on for nine or ten, or even
twenty or more successions; and there is no very good
reason to say how soon it might terminate, or how long
it might not go on if the proper conditions of warmth
and nourishment were kept up.

Sexual reproduction is quite a distinct matter. Here,
in all these cases, what is required is the detachment
of two portions of the parental organisms, which
portions we know as the egg or the spermatozoon.
In plants it is the ovule and the pollen-grain, as in
the flowering plants, or the ovule and the antherozooid,
as in the flowerless. Among all forms of animal life,
the spermatozoa proceed from the male sex, and the
egg is the product of the female. Now, what is
remarkable about this mode of reproduction is this,
that the egg by itself, or the spermatozoa by them-
selves, are unable to assume the parental form; but
if they be brought into contact with one another,
the effect of the mixture of organic substances pro-

HEREDITARY TRANSMISSION AND VARIATION, 87

ceeding from two sources appears to confer an altogether
new vigour to the mixed product. This process is
brought about, as we all know, by the sexual inter-
course of the two sexes, and is called the act of impreg-
nation. ‘The result of this act on the part of the male
and female is, that the formation of a new being is sct
up in the ovule or egg; this ovule or egg soon begins
to be divided and subdivided, and to be fashioned into
various complex organisms, and eventually to develop
into the form of one of its parents, as I explained in
the first lecture. These are the processes by which
the perpetuation of organic beings is secured. Why
there should be the two modes—why this re-invigora-
tion should be required on the part of the female
element we do not know; but it is most assuredly the
fact, and it is presumable, that, however long the
process of asexual multiplication could be continued,—
I say there is good reason to believe that it would
come to an end if a new commencement were not
obtained by a conjunction of the two sexual elements.

That character which is common to these two dis-
tinct processes is this, that, whether we consider the
reproduction, or perpetuation, or modification of
organic beings as they take place asexually, or as
they may take place sexually,—in either case, I say,
the offspring has a constant tendency to assume,
speaking generally, the character of the parent. As
I said just now, if you take a slip of a plant, and
tend it with care, it will eventually grow up and de-
velop into a plant hke that from which it had sprung ;
and this tendency is so strong that, as gardeners know,

88 THE PERPETUATION OF LIVING BEINGS,

this mode of multiplying by means of cuttings is the
only secure mode of prepagating very many varieties of
plants; the peculiarity of the primitive stock seems to
be better preserved if you propagate it by means of a
slip than if you resort to the sexual mode.

Again, in experiments upon the lower animals, such
as the polype, to which I have referred, it is most
extraordinary that, although cut up into various pieces,
each particular piece will grow up into the form of the
primitive stock; the head, if separated, will reproduce
the body and the tail; and if you cut off the tail, you
will find that that will reproduce the body and all the
rest of the members, without in any way deviating
from the plan of the organism from which these por-
tions have been detached. And so far does this go,
that some experimentalists have carefully examined
the lower orders of animals,—among them the Abbé
Spallanzani, who made a number of experiments upon
snails and salamanders,—and have found that they
might mutilate them to an incredible extent; that
you might cut off the jaw or the greater part of
the head, or the leg or the tail, and repeat the ex-
periment several times, perhaps, cutting off the same
member again and again; and yet each of those
types would be reproduced according to the primitive
type: nature making no mistake, never putting on a
fresh kind of leg, or head, or tail, but always tending
to repeat and to return to the primitive type.

It is the same in sexual reproduction: it is a matter
of perfectly common experience, that the tendency on
the part of the offspring always is, speaking broadly,

HEREDITARY TRANSMISSION AND VARIATION. 89

to reproduce the form of the parents. The proverb has
it that the thistle does not bring forth grapes; so,
among ourselves, there is always a likeness, more or less-
marked and distinct, between children and their parents.
That is a matter of familiar and ordinary observation.
We notice the same thing occurring in the cases of the
domestic animals—dogs, for instance, and their off-
spring. In all these cases of propagation and perpetu-
ation, there seems to be a tendency in the offspring to
take the characters of the parental organisms. To that
tendency a special name is given—and as I may very
often use it, I will write it up here on this black-board
that you may remember it—it is called Atavism; it
expresses this tendency to revert to the ancestral type,
and comes from the Latin word atavus, ancestor.

Well, this Atavism which I shall speak of, is, as I
said before, one of the most marked and striking
tendencies of organic beings; but, side by side with
this hereditary tendency there is an equally distinct
and remarkable tendency to variation. The tendency
to reproduce the original stock has, as it were, its
limits, and side by side with it there is a tendency to
vary 1n certain directions, as if there were two opposing
powers working upon the organic being, one tending
to take it in a straight line, and the other tending to
make it diverge from that straight line, first to one side
and then to the other.

So that you see these two tendencies need not pre-
cisely contradict one another, as the ultimate result
may not always be very remote from what would have
been the case if the line had been quite straight.

90 THE PERPETUATION OF LIVING BEINGS,

This tendency to variation is less marked in that
mode of propagation which takes place asexually ;
it is in that mode that the minor characters of
animal and vegetable structures are most completely
preserved, Still, it will happen sometimes, that the
gardener, when he has planted a cutting of some
favourite plant, will find, contrary to his expectation,
that the slip grows up a little different from the
primitive stock—that it produces flowers of a differ-
ent colour or make, or some deviation in one way or
another, This is what is called the ‘sporting’ of plants.

In animals the phenomena of asexual propagation
are so obscure, that at present we cannot be said to
know much about them; but if we turn to that mode
of perpetuation which results from the sexual process,
then we find variation a perfectly constant occurreuice,
to a certain extent ; and, indeed, I think that a certain
amount of variation from the primitive stock is the
necessary result of the method of sexual propagation
itself; for, inasmuch as the thing propagated proceeds
from two organisms of different sexes and different
makes and temperaments, and as the offspring is to
be either of one sex or the other, it is quite clear that
it cannot be an exact diagonal of the two, or it would
be of no sex at all; it cannot be an exact intermediate
form between that of each of its parents—it must
deviate to one side or the other. You do not find
that the male follows the precise type of the male
parent, nor does the female always inherit the precise
characteristics of the mother,—there is always a pro-
portion of the female character in the male offspring,

HEREDITARY TRANSMISSION AND VARIATION. 91

and of the male character in the female offspring.
That must be quite plain to all of you who have looked
at all attentively on your own children or those of
your neighbours ; you will have noticed how very often
it may happen that the son shall exhibit the maternal
type of character, or the daughter possess the charac-
teristics of the father’s family. There are all sorts
of intermixtures and intermediate conditions between
the two, where complexion, or beauty, or fifty other
different peculiarities belonging to either side of the
house, are reproduced in other members of the same
family. Indeed, it is sometimes to be remarked in
this kind of variation, that the variety belongs, strictly
speaking, to neither of the immediate parents; you
will see a child in a family who is not like either
its father or its mother; but some old person who
knew its grandfather or grandmother, or, it may be,
an uncle, or, perhaps, even a more distant relative,
will see a great similarity between the child and one
of these. In this way it constantly happens that the
characteristic of some previous member of the family
comes out and is reproduced and recognized in the
most unexpected manner.

But apart from that matter of general experience,
there are some cases which put that curious mixture in
a very clear light. You are aware that the offspring of
the Ass and the Horse, or rather of the he-Ass and the
Mare, is what is called a Mule; and, on the other hand,
the offspring of the Stallion and the she-Ass is what is
called a Hinny. It is a very rare thing in this country
to see a Hinny. I never saw one myself; but they have

92 THE PERPETUATION OF LIVING BEINGS,

been very carefully studied. Now, the curious thing is
this, that although you have the same elements in
the experiment in each case, the offspring is entirely
different in character, according as the male influence
comes from the Ass or the Horse. Where the Ass is
the male, as in the case of the Mule, you find that the
head is like that of the Ass, that the ears are long, the
tail is tufted at the end, the feet are small, and the
voice is an unmistakable bray; these are all points
of similarity to the Ass; but, on the other hand, the
barrel of the body and the cut of the neck are much
more like those of the Mare. Then, if you look at the
Hinny,—the result of the union of the Stallion and
the she-Ass, then you find it is the Horse that has the
predominance; that the head is more like that of the
Horse, the ears are shorter, the legs coarser, and the
type is altogether altered; while the voice, instead of
being a bray, is the ordinary neigh of the Horse.
Here, you see, is a most curious thing: you take
exactly the same elements, Ass and Horse, but you
combine the sexes in a different manner, and the result
is modified accordingly. You have in this case, how-
ever, a result which is not general and universal—there
is usually an important preponderance, but not always
on the same side.

Here, then, is one intelligible, and, perhaps, neces-
sary cause of variation: the fact, that there are two
sexes sharing in the production of the offspring, and
that the share taken by each is different and variable,
not only for each combination, but also for different
members of the same family.

HEREDITARY TRANSMISSION AND VARIATION. 93

Secondly, there is a variation, to a certain extent,—
though in all probability the influence of this cause
has been very much exaggerated—but there is no doubt
that variation is produced, to a certain extent, by what
are commonly known as external conditions,—such as
temperature, food, warmth, and moisture. In the long
run, every variation depends, in some sense, upon ex-
ternal conditions, seeing that everything has a cause
of its own. I use the term “ external conditions ” now
in the sense in which it is ordinarily employed: certain
it is, that external conditions have a definite effect.
You may take a plant which has single flowers, and
by dealing with the soil, and nourishment, and so on,
you may by-and-by convert single flowers into double
flowers, and make thorns shoot out into branches.
You may thicken or make various modifications in the
shape of the fruit. In animals, too, you may produce
analogous changes in this way, as in the case of that
deep bronze colour which persons rarely lose after
having passed any length of time in tropical countries.
You may also alter the development of the muscles
very much, by dint of training; all the world knows
that exercise has a great effect in this way; we always
expect to find the arm of a blacksmith hard and wiry,
and possessing a large development of the brachial
muscles. No doubt, training, which is one of the forms
of external conditions, converts what are originally
only instructions, teachings, into habits, or, in other
words, into organizations, to a great extent; but this
second cause of variation cannot be considered to be
by any means a large one. The third cause that I

94. THE PERPETUATION OF LIVING BEINGS,

have to mention, however, is a very extensive one.
It is one that, for want of a better name, has been
called ‘‘ spontaneous variation;” which means that
when we do not know anything about the cause of
phenomena, we call it spontaneous. In the orderly
chain of causes and effects in this world, there are very
few things of which it can be said with truth that they
are spontaneous. Certainly not in these physical mat-
ters,—in these there is nothing of the kind,—every-
thing depends on previous conditions. But when we
cannot trace the cause of phenomena, we call them
spontaneous.

Of these variations, multitudinous as they: are, but
little is known with perfect accuracy. I will mention
to you some two or three cases, because they are very
remarkable in themselves, and also because I shall want
to use them afterwards. Réaumur, a famous French
naturalist, a great many years ago, in an essay which
he wrote upon the art of hatching chickens,—which
was indeed a very curious essay, — had occasion to
speak of variations and monstrosities. One very re-
markable case had come under his notice of a variation
in the form of a human member, in the person of a
Maltese, of the name of Gratio Kelleia, who was born
with six fingers upon each hand, and the like number
of toes to each of his feet. That was a case of spon-
taneous variation. Nobody knows why he was born
with that number of fingers and toes, and as we don’t
know, we call it a case of “spontaneous” variation.
There is another remarkable case also. . I select these,
because they happen to have been observed and noted

HEREDITARY TRANSMISSION AND VARIATION. 95

very carefully at the time. It frequently happens that a
variation occurs, but the persons who notice it do not
take any care in noting down the particulars, until at
length, when inquiries come to be made, the exact
circumstances are forgotten ; and hence, multitudinous

? variations, it is ex-

as may be such “ spontaneous’
ceedingly difficult to get at the origin of them.

The second case is one of which you may find the
whole details in the “ Philosophical Transactions” for
the year 1813, in a paper communicated by Colonel
Humphrey to the President of the Royal Society,—
“On a new Variety in the Breed of Sheep,”’ giving an
account of a very remarkable breed of sheep, which
at one time was well known in the northern states of
America, and which went by the name of the Ancon or
the Otter breed of sheep. In the year 1791, there was a
farmer of the name of Seth Wright in Massachusetts,
who had a flock of sheep, consisting of a ram and, I
think, of some twelve or thirteen ewes. Of this flock
of ewes, one at the breeding-time bore a lamb which
was very singularly formed; it had a very long body,
very short legs, and those legs were bowed! I will
tell you by-and-by how this singular variation in the
breed of sheep came to be noted, and to have the
prominence that it now has. For the present, | men-
tion only these two cases; but the extent of variation
in the breed of animals is perfectly obvious to any one
who has studied natural history with ordinary atten-
tion, or to any person who compares animals with
others of the same kind. It is strictly true that there
are never any two specimens which are exactly alike;

96 THE PERPETUATION OF LIVING BEINGS,

however similar, they will always differ in some cer-
tain particular.

Now let us go back to Atavism,—to the hereditary
tendency I spoke of. What will come of a variation
when you breed from it, when Atavism comes, if I may
say so, to intersect variation? The two cases of which I
have mentioned the history, give a most excellent illus-
tration of what occurs. Gratio Kelleia, the Maltese,
married when he was twenty-two years of age, and, as I
suppose there were no six-fingered ladies in Malta, he
married an ordinary five-fingered person. The result
of that marriage was four children; the first, who was
christened Salvator, had six fingers and six toes, like
his father; the second was George, who had five
fingers and toes, but one of them was deformed, show-
ing a tendency to variation; the third was André; he
had five fingers and five toes, quite perfect ; the fourth
was a girl, Marie; she had five fingers and five toes, but
her thumbs were deformed, showing a tendency towards
the sixth.

These children grew up, and when they came to
adult years, they all married, and of course it happened
that they all married five-fingered and five-toed persons.
Now let us see what were the results. Salvator had
four children; they were two boys, a girl, and another
boy : the first two boys and the girl were six-fingered
and six-toed like their grandfather ; the fourth boy had
only five fingers and five toes. George had only. four
children: there were two girls with six fingers and six
toes; there was one girl with six fingers and five toes
on the right side, and five fingers and five toes on the

HEREDITARY TRANSMISSION AND VARIATION. 97

left side, so that she was half and half. The last, a
boy, had five fingers and five toes. The third, André,
you will recollect, was perfectly well-formed, and he
had many children whose hands and feet were all regu-
larly developed. Marie, the last, who, of course, mar-
ried a man who had only five fingers, had four chil-
dren: the first, a boy, was born with six toes, but the
other three were normal.

Now observe what very extraordinary phenomena
are presented here. You have an accidental variation
arising from what you may call a monstrosity; you
have that monstrosity tendency or variation diluted in
the first instance by an admixture with a female of
normal construction, and you would naturally expect
that, in the results of such an union, the monstrosity, if
repeated, would be in equal proportion with the normal
type; that is to say, that the children would be half
and half, some taking the peculiarity of the father, and
the others being of the purely normal type of the
mother; but you see we have a great preponderance of
the abnormal type. Well, this comes to be mixed once
more with the pure, the normal type, and the abnor-
mal is again produced in large proportion, notwith-
standing the second dilution. Now what would have
happened if these abnormal types had intermarried with
each other; that is to say, suppose the two boys of Sal-
vator had taken it into their heads to marry their first
cousins, the two first girls of George, their uncle? You
will remember that these are all of the abnormal type
of their grandfather. The result would probably have
been, that their offspring would have been in every

93 THE PERPETUATION OF LIVING BEINGS,

case a further development of that abnormal type.
You see it is only in the fourth, in the person of
Marie, that the tendency, when it appears but slightly
in the second generation, is washed out in the third,
while the progeny of André, who escaped in the first
instance, escape altogether,

We have in this case a good example of nature’s
tendency to the perpetuation of a variation. Here it
is certainly a variation which carried with it no use
or benefit; and yet you see the tendency to perpetua-
tion may be so strong, that, notwithstanding a great
admixture of pure blood, the variety continues itself
up to the third generation, which is largely marked
with it. In this case, as I have said, there was no
means of the second generation intermarrying with any
but five-fingered persons, and the question naturally
suggests itself, What would have been the result of such
marriage? Réaumur narrates this case only as far as
the third generation. Certainly it would have been an
exceedingly curious thing if we could have traced this
matter auy further; had the cousins intermarried, a
six-fingered variety of the human race might have
been set up.

To show you that this supposition is by no means an
unreasonable one, let me now point out what took place
in the case of Seth Wright’s sheep, where it happened
to be a matter of moment to him to obtain a breed
or raise a flock of sheep like that accidental variety
that I have described—and I will tell you why. In
that part of Massachusetts where Seth Wright was
living, the fields were separated by fences, and the

HEREDITARY TRANSMISSION AND VARIATION. 99)

sheep, which were very active and robust, would roam
abroad, and without much difficulty jump over these
fences into other people’s farms. As a matter of
course, this exuberant activity on the part of the
sheep constantly gave rise to all sorts of quarrels,
bickerings, and contentions among the farmers
of the neighbourhood; so it occurred to Seth
Wright, who was, like his successors, more or less
7eute, that if he could get a stock of sheep like
those with the bandy legs, they would not be able to
jump over the fences so readily, and he acted upon
that idea. He killed his old ram, and as soon
as the young one arrived at maturity, he bred
altogether from it. The result was even more
striking than in the human experiment which I
mentioned just now. Colonel Humphreys testifies
that it always happened that the offspring were
either pure Ancons or pure ordinary sheep; that in
no case was there any mixing of the Ancons with the
others. In consequence of this, in the course of a very
few years, the farmer was able to get a very considerable
flock of this variety, and a large number of them were
spread throughout Massachusetts. Most unfortunately, °
however—I suppose it was because they were so com-
mon—nobody took enough notice of them to preserve
their skeletons; and although Colonel Humphreys
states that he sent a skeleton to the president of the
Royal Society at the same time that he forwarded his
paper, and I am afraid that the variety has entirely
disappeared ; for a short time after these sheep had
become prevalent in that district, the Merino sheep

100 THE PERPETUATION OF LIVING BEINGS,

were introduced; and as their wool was much more
valuable, and as they were a quiet race of sheep,
and showed no tendency to trespass or jump over
fences, the Otter breed of sheep, the wool of which
was inferior to that of the Merino, was gradually
allowed to die out.

You see that these facts illustrate perfectly well
what may be done if you take care to breed from stocks
that are similar to each other. After having got a varia-
tion, if, by crossing a variation with the original stock,
you multiply that variation, and then take care to keep
that variation distinct from the original stock, and
make them breed together,—then you may almost cer-
tainly produce a race whose tendency to continue the
variation is exceedingly strong.

This is what is called “selection ;” and it is by exactly
the same process as that by which Seth Wright bred
his Ancon sheep, that our breeds of cattle, dogs, and
fowls, are obtained. There are some possibilities of
exception, but still, speaking broadly, I may say that
this is the way in which all our varied races of domestic
animals have arisen; and you must understand that
it is not one peculiarity or one characteristic alone
in which animals may vary. There is not a single
peculiarity or characteristic of any kind, bodily or
mental, in which offspring may not vary to a certain
extent from the parent and other animals.

Among ourselves this is well known. The simplest
physical peculiarity is mostly reproduced. I knowa
case of a man whose wife has the lobe of one of her
ears a little flattened. An ordinary observer might

HEREDITARY TRANSMISSION AND VARIATION. 101]

scarcely notice it, and yet every one of her children
has an approximation to the same peculiarity to some
extent. If you look at the other extreme, too, the
gravest diseases, such as gout, scrofula, and consump-
tion, may be handed down with just the same certainty
and persistence as we noticed in the perpetuation of
the bandy legs of the Ancon sheep.

However, these facts are best illustrated in animals,
and the extent of the variation, as is well known, is
very remarkable in dogs. For example, there are some
dogs very much smaller than others; indeed, the
variation is so enormous that probably the smallest dog
would be about the size of the head of the largest ;
there are very great variations in the structural forms
not only of the skeleton but also in the shape of the
skull, and in the proportions of the face and the
disposition of the teeth.

The Pointer, the Retriever, Bulldog, and the Terrier,
differ very greatly, and yet there is every reason to
believe that every one of these races has arisen from
the same source,—that all the most important races
have arisen by this selective breeding from accidental
variation.

A still more striking case of what may be done by
selective breeding, and it is a better case, because
there is no chance of that partial infusion of error
to which I ailuded, has been studied very carefully by
Mr. Darwin,—the case of the domestic pigeons. I
dare say there may be some among you who may be
pigeon fanciers, and I wish you to understand that
in approaching the subject, I would speak with all

102 THE PERPETUATION OF LIVING BEINGS,

humility and hesitation, as I regret to say that I am
not a pigeon fancier. I know it is a great art and
mystery, and a thing upon which a man must not
speak lightly; but I shall endeavour, as far as my
understanding goes, to give you a summary of the
published and unpublished information which I have
gained from Mr. Darwin.

Among the enormous variety,—I believe there are
somewhere about a hundred and fifty kinds of
pigeons,—there are four kinds which may be selected
as representing the extremest divergences of one kind
from another. Their names are the Carrier, the Pouter,
the Fantail, and the Tumbler. In these large diagrams
that I have here they are each represented in their
relative sizes to each other. This first one is the Car-
rier ; you will notice this large excrescence on its beak ;
it has a comparatively small head ; there is a bare space
round the eyes; it has a long neck, a very long beak,
very strong legs, large feet, long wings, and so on.
The second one is the Pouter, a very large bird, with
very long legs and beak. It is called the Pouter
because it is in the habit of causing its gullet to swell
up by inflating it with air. I should tell you that all
pigeons have a tendency to do this at times, but in the
Pouter it is carried to an enormous extent. The birds
appear to be quite proud of their power of swelling and
puffing themselves out in this way; and I think it is
about as droll a sight as you can well see to look at a
cage full of these pigeons puffing and blowing them-
selves out in this ridiculous manner.

This diagram is a representation of the third kind

HEREDITARY TRANSMISSION AND VARIATION. 103:

I mentioned—the Fantail. It is, you see, a small bird,
with exceedingly small legs and a very small beak. It
is most curiously distinguished by the size and extent
of its tail, which, instead of containing fourteen
feathers, may have many more,—say thirty, or even
more—I believe there are some with as many as forty-
two. This bird has a curious habit of spreading out the
feathers of its tail in such a way that they reach
forward, and touch its head; and if this can be accom-
plished, I believe it is looked upon as a point of great
beauty.

But here is the last great variety,—the Tumbler ; and
of that great variety, one of the principal kinds, and
one most prized, is the specimen represented here—the
short-faced Tumbler. Its beak, you see, is reduced to
a mere nothing. Just compare the beak of this one and
that of the first one, the Carrier—I believe the ortho-
dox comparison of the head and beak of a thoroughly
well-bred Tumbler is to stick an oat into a cherry,
and that will give you the proper relative proportions
of the head and beak. The feet and legs are exceed-
ingly small, and the bird appears to be quite a dwarf
when placed side by side with this great Carrier.

These are differences enough in regard to their ex-
ternal appearance; but these differences are by no
means the whole or even the most important of the dif-
ferences which obtain between these birds. There is
hardly a single point of their structure which has not
become more or less altered ; and to give you an idea
of how extensive these alterations are, I have here some
very good skeletons, for which I am indebted to my

104: THE PERPETUATION OF LIVING BEINGS,

friend Mr. Tegetmeier, a great authority in these
matters; by means of which, if you examine them
by-and-by, you will be able to see the enormous dif-
ference in their bony structures.

I had the privilege, some time ago, of access to
some important MSS. of Mr. Darwin, who, I may tell
you, has taken very great pains and spent much
valuable time and attention on the investigation of
these variations, and getting together all the facts
that bear upon them. I obtained from these MSS.
the following summary of the differences between the
domestic breeds of pigeons; that is to say, a notifi-
cation of the various points in which their organiza-
tion differs. In the first place, the back of the skull
may differ a good deal, and the development of the
bones of the face may vary a great deal; the back
varies a good deal; the shape of the lower jaw varies ;
the tongue varies very greatly, not only in correlation
to the length and size of the beak, but it seems
also to have a kind of independent variation of its
own. Then the amount of naked skin round the eyes,
and at the base of the beak, may vary enormously; so
may the length of the eyelids, the shape of the nostrils,
and the length of the neck. I have already noticed the
habit of blowing out the gullet, so remarkable in the
Pouter, and comparatively so in the others. There are
great differences, too, in the size of the female and the
male, the shape of the body, the number and width of
the processes of the ribs, the development of the ribs,
and the size, shape, and development of the breastbone.
We may notice, too,—and I mention the fact because

HEREDITARY TRANSMISSION AND VARIATION. 105

it has been disputed by what is assumed to be high
authority,—the variation in number of the sacral ver-
tebrze. The number of these varies from eleven to four-
teen, and that without any diminution in the number
of the vertebrze of the back or of the tail. Then the
number and position of the tail-feathers may vary
enormously, and so may the number of the primary
and secondary feathers of the wings. Again, the
length of the feet and of the beak,—although they
have no relation to each other, yet appear to go
together,—that is, you have a long beak wherever you
have long feet. There are differences also in the
periods of the acquirement of the perfect plumage,—
the size and shape of the eggs,—the nature of flight,
and the powers of flight,—so-called “homing” birds
having enormous flying powers ;* while, on the other
hand, the little Tumbler is so called because of its
extraordinary faculty of turning head over heels in the
air, instead of pursuing a distinct course. And, lastly,
the dispositions and voices of the birds may vary.
Thus the case of the pigeons shows you that there is
hardly a single particular,—whether of instinct, or
habit, or bony structure, or of plumage,—of either
the internal economy or the external shape, in which
some variation or change may not take place, which,
by selective breeding, may become perpetuated, and
form the foundation of, and give rise to, a new race.

* The “Carrier,” I learn from Mr. Tegetmeier, does not carry; a
hich-bred bird of this breed being but a poor flier. The birds which
fly long distances, and come home,—“ homing ” birds,—and are con-
sequently used as carriers, are not “ carriers” in the fancy sense.

106 THE PERPETUATION OF LIVING BEINGS.

If you carry in your mind’s eye these four
varieties of pigeons, you will bear with you as good a
notion as you can have, perhaps, of the enormous
extent to which a deviation from a primitive type
may be carried by means of this process of selective
breeding.

LECTURE V.

THE CONDITIONS OF EXISTENCE AS
AFFECTING THE PERPETUATION OF
LIVING BEINGS.

In the last Lecture I endeavoured to prove to you
that, while, as a general rule, organic beings tend to
reproduce their kind, there is in them, also, a con-
stantly recurring tendency to vary—to vary to a greater
or to a less extent. Such a variety, I pointed out
to you, might arise from causes which we do not
understand ; we therefore called it spontaneous; and
it might come into existence as a definite and
marked thing, without any gradations between itself
and the form which preceded it. I further pointed out,
that such a variety having once arisen, might be per-
petuated to some extent, and indeed to a very marked
extent, without any direct interference, or without any
exercise of that process which we called selection. And
then I stated further, that by such selection, when
exercised artificially—if you took care to breed only
from those forms which presented the same peculiarities
of any variety which had arisen in this manner—the
variation might be perpetuated, as far as we can see,
indefinitely.

F2

108 CONDITIONS AFFECTING THE

The next question, and it is an important one for
us, is this: Is there any limit to the amount of varia-
tion from the primitive stock which can be produced
by this process of selective breeding? In considering
this question, it will be useful to class the character-
istics, in respect of which organic beings vary, under
two heads: we may consider structural characteristics,
and we may consider physiological characteristics.

In the first place, as regards structural charac-
teristics, I endeavoured to show you, by the skeletons
which I had upon the table, and by reference to a
great many well-ascertained facts, that the different
breeds of Pigeons, the Carriers, Pouters, and Tumblers,
might vary in any of their internal and important
structural characters to a very great degree; not only
might there be changes in the proportions of the skull,
and the characters of the feet and beaks, and so on;
but that there might be an absolute difference in the
number of the vertebrz of the back, as in the sacral
vertebre of the Pouter; and so great is the extent
of the variation in these and similar characters that
I pomted out to you, by reference to the skeletons
and the diagrams, that these extreme varieties may
absolutely differ more from one another in their struc-
tural characters than do what naturalists call distinct
Srecizes of pigeons; that is to say, that they differ
so much in structure that there is a greater difference
between the Pouter and the Tumbler than there is
between such wild and distinct forms as the Rock
Pigeon or the Ring Pigeon, or the Ring Pigeon and
the Stock Dove; and indeed the differences are of
greater value than this, for the structural differences

PERPETUATION OF LIVING BEINGS. 109

between these domesticated pigeons are such as would
be admitted by a naturalist, supposing he knew nothing
at all about their origin, to entitle them to constitute
even distinct genera.

As I have used this term Spectres, and shall probably
use it a good deal, I had better perhaps devote a word
or two to explaining what I mean by it.

Animals and plants are divided into groups, which
become gradually smaller, beginning with a Kinepom,
which is divided into Sus-Kinepoms; then come the
smaller divisions called Provinces; and so on from a
Province to a Crass, from a Crass to an OrpeEr, from
Orpers to Fami.ies, and from these to Genera, until
we come at length to the smallest groups of animals
which can be defined one from the other by constant
characters, which are not sexual; and these are what
naturalists call Species in practice, whatever they may
do in theory.

Tf in a state of nature you find any two groups of
living beings, which are separated one from the other
by some constantly-recurring characteristic, I don’t
care how slight and trivial, so long as it is defined
and constant, and does not depend on sexual pecu-
liarities, then all naturalists agree in calling them two
species ; that is what is meant by the use of the word
species—that is to say, it is, for the practical naturalist,
a mere question of structural differences.*

We have seen now—to repeat this point once more,
and it is very essential that we should rightly under-

* I lay stress here on the practical signification of “Species.”
Whether a physiological test between species exist or not, it is
hardly ever applicable by the practical naturalist.

110 CONDITIONS AFFECTING THE

stand it—we have seen that breeds, known to have
been derived from a common stock by selection, may
be as different in their structure from the original
stock as species may be distinct from each other.

But is the like true of the physiological characteris-.
tics of animals? Do the physiological differences of
varieties amount in degree to those observed between
forms which naturalists call distinct species? This is.
a most important point for us to consider.

As regards the great majority of physiological cha-
racteristics, there is no doubt that they are capable of.
being developed, increased, and modified by selection.

There is no doubt that breeds may be made as dif-
ferent as species in many physiological characters. I
have already pointed out to you very briefly the different
habits of the breeds of Pigeons, all of which depend
upon their physiological peculiarities,—as the peculiar
habit of tumbling, in the Tumbler,—the peculiarities of
flight, in the “homing” birds,—the strange habit of
spreading out the tail, and walking in a peculiar fashion,
in the Fantail,—and, lastly, the habit of blowing out
the gullet, so characteristic of the Pouter. These are
all due to physiological modification, and in all these
respects these birds differ as much from each other as
any two ordinary species do.

So with Dogs in their habits and instincts. It is a
physiological peculiarity which leads the Greyhound to
chase its prey by sight,—that enables the Beagle to
track it by the scent,—that impels the Terrier to its
rat-hunting propensity,—and that leads the Retriever
to its habit of retrieving. These habits and instincts
are all the results of physiological differences and pecu-

PERPETUATION OF LIVING BEINGS. ae.

liarities, which have been developed from a common
stock, at least there is every reason to believe so. But it
is a most singular circumstance, that while you may run
through almost the whole series of physiological pro-
‘cesses, without finding a check to your argument, you
‘come at last to a point where you do find a check, and
that is in the reproductive processes. For there is a most
singular circumstance in respect to natural species—at
least about some of them—and it would be sufficient
for the purposes of this argument, if it were true of only
one of them, but there is, in fact, a great number of
such cases—and that is, that similar as they may appear
to be to mere races or breeds, they present a marked
peculiarity in the reproductive process. If you breed
from the male and female of the same race, you of
course have offspring of the like kind, and if you
make the offspring breed together, you obtain the
same result, and if you breed from these again, you
will still have the same kind of offspring; there is
no check. But if you take members of two distinct
species, however similar they may be to each other,
and make them breed together, you will find a check,
with some modifications and exceptions, however, which
I shall speak of presently. If you cross two such
species with each other, then,—although you may
get offspring in the case of the first cross, yet, if you
attempt to breed from the products of that crossing,
which are what are called Hysrips —that is, if you
couple a male and a female hybrid —then the result
is that in ninety-nine cases out of a hundrel you will
get no offspring at all: there will be no result what-
soever.

ty CONDITIONS AFFECTING THE

The reason of this is quite obvious in some cases;
the male hybrids, although possessing all the external
appearances and characteristics of perfect animals, are
physiologically imperfect and deficient in the structural
parts of the reproductive elements necessary to genera-
tion. It is said to be invariably the case with the male
mule, the cross between the Ass and the Mare; and
hence it is, that, although crossing the Horse with the
Ass is easy enough, and is constantly done, as far as I
am aware, if you take two mules, a male and a female,
and endeavour to breed from them, you get no offspring
whatever; no generation will take place. This is what
is called the sterility of the hybrids between two dis-
tinct species.

You see that this is a very extraordinary circum-
stance; one does not see why it should be. The
common teleological explanation is, that it is to prevent
the impurity of the blood resulting from the crossing
of one species with another, but you see it does not in
reality do anything of the kind. There is nothing in
this fact that hybrids cannot breed with each other, to
establish such a theory; there is nothing to prevent
the Horse breeding with the Ass, or the Ass with the
Horse. So that this explanation breaks down, as a
great many explanations of this kind do, that are only
founded on mere assumptions.

Thus you see that there is a great difference between
*‘mongrels,” which are crosses between distinct races,
and ‘hybrids,’ which are crosses between distinct
species. The mongrels are, so far as we know, fertile
with one another. But between species, in many cases,
you cannot succeed in obtaining even the first cross:

PERPETUATION OF LIVING BEINGS. 113

at any rate it is quite certain that the hybrids are often
absolutely infertile one with another.

Here is a feature, then, great or small as it may be,
which distinguishes natural species of animals. Can
we find any approximation to this in the different races
known to be produced by selective breeding from a
common stock? Up to the present time the answer to
that question is absolutely a negative one. As far as we
know at present, there is nothing approximating to
this check. In crossing the breeds between the Fan-
tail and the Pouter, the Carrier and the Tumbler, or
any other variety or race you may name—so far as we
know at present—there is no difficulty in breeding
together the mongrels. ‘Take the Carrier and the
Fantail, for instance, and let them represent the Horse
and the Ass in the case of distinct species ; then you have,
as the result of their breeding, the Carrier-Fantail
mongrel,—we will say the male and female mongrel,—
and, as far as we know, these two when crossed would
not be less fertile than the original cross, or than Carrier
with Carrier. Here, you see, is a physiological contrast
between the races produced by selective modification and
natural species. I shall inquire into the value of this
fact, and of some modifying circumstances by and by ;
for the present I merely put it broadly before you.

But while considering this question of the limitations
of species, a word must be said about what is called
Recurrence—the tendency of races which have been
developed by selective breeding from varieties to
return to their primitive type. This is supposed by
many to put an absolute limit to the extent of selective
and all other variations. People say, “It is all very

114 CONDITIONS AFFECTING THE

well to talk about producing these different races, but
you know very well that if you turned all these birds
wild, these Pouters, and Carriers, and so on, they would
all return to their primitive stock.” This is very com-
monly assumed to be a fact, and it is an argument that
is commonly brought forward as conclusive; but if you.
will take the trouble to inquire into it rather closely, I
think you will find that it is not worth very much.
The first question of course is, Do they thus return to-
the primitive stock? And commonly as the thing is.
assumed and accepted, it is extremely difficult to get
anything like good evidence of it. It is constantly
said, for example, that if domesticated Horses are turned
wild, as they have been in some parts of Asia Minor
and South America, that they return at once to the
primitive stock from which they were bred. But the
first answer that you make to this assumption is, to ask
who knows what the primitive stock was; and the
second answer is, that in that case the wild Horses of
Asia Minor ought to be exactly like the wild Horses.
of South America. If they are both like the same
thing, they ought manifestly to be like each other!’
The best authorities, however, tell you that it is quite
different. The wild Horse of Asia is said to be of a
dun colour, with a largish head, and a great many other
peculiarities ; while the best authorities on the wild
Horses of South America tell you that there is nothing
of this sort in the wild Horses there; the cnt of their
heads is very different, and they are commonly chest-
nut or bay-coloured. It is quite clear, therefore, that
as by these facts there ought to have been two primitive
stocks, they go for nothing in support of the assump-

PERPETUATION OF LIVING BEINGS. 115

tion that races recur to one primitive stock, and so far
as this evidence is concerned, it falls to the ground.

Suppose for a moment that it were so, and that
domesticated races, when turned wild, did return to
some common condition, I cannot see that this would
prove much more than that similar conditions are
likely to produce similar results; and that when you
‘take back domesticated animals into what we call
natural conditions, you do exactly the same thing as if
-you carefully undid all the work you had gone through,
for the purpose of bringing the animal from its wild to
its domesticated state. I do not see anything very
wonderful in the fact, if it took all that trouble to
get it from a wild state, that it should go back into its
original state as soon as you remove the conditions
which produced the variation to the domesticated form.
‘There is an important fact, however, forcibly brought
forward by Mr. Darwin, which has been noticed in
connection with the breeding of domesticated pigeons ;
and it is, that however different these breeds of pigeons
may be from each other, and we have already noticed
the great differences in these breeds, that if, among
-any of those variations, you chance to have a blue
pigeon turn up, it will be sure to have the black bars
across the wings, which are characteristic of the original
wild stock, the Rock Pigeon.

Now, this is certainly a very remarkable circum-
stance; but I do not see myself how it tells very strongly
-either one way or the other. I think, in fact, that
this argument in favour of recurrence to the primitive
type might prove a great deal too much for those
who so constantly bring it forward. For example,

116 CONDITIONS AFFECTING THE

Mr. Darwin has very forcibly urged, that nothing is
commoner than if you examine a dun horse—and
I had an opportunity of verifying this illustration
lately, while in the islands of the West Highlands,
where there are a great many dun horses—to find that
horse exhibit a long black stripe down his back, very
often stripes on his shoulder, and very often stripes
on his legs. I, myself, saw a pony of this description
a short time ago, in a baker’s cart, near Rothesay, in
Bute: it had the long stripe down the back, and stripes
on the shoulders and legs, just like those of the Ass,
the Quagga, and the Zebra. Now, if we interpret the
theory of recurrence as applied to this case, might it
not be said that here was a case of a variation exhibit-
ing the characters and conditions of an animal occu-
pying something like an intermediate position between
the Horse, the Ass, the Quagga, and the Zebra, and
from which these had been developed? In the same
way with regard even to Man. Every anatomist will
tell you that there is nothing commoner, in dissecting
the human body, than to meet with what are called
muscular variations—that is, if you dissect two bodies
very carefully, you will probably find that the modes
of attachment and insertion of the muscles are not
exactly the same in both, there being great pecu-
liarities in the mode in which the muscles are
arranged ; and it is very singular, that in some
dissections of the human body you will come upon
arrangements of the muscles very similar indeed to the
same parts in the Apes. Is the conclusion in that case
to be, that this is like the black bars in the case of
the Pigeon, and that it indicates a recurrence to the

PERPETUATION OF LIVING BEINGS. 117

primitive type from which the animals have been pro-
bably developed? Truly, I think that the opponents of
modification and variation had better leave the argu-
ment of recurrence alone, or it may prove altogether
too strong for them.

To sum up,—the evidence as far as we have gone
is against the argument as to any limit to divergences,
so far as structure is concerned; and in favour of
a physiological limitation. By selective breeding we
can produce structural divergences as great as those of
species, but we cannot produce equal physiological diver-
gences. For the present I leave the question there.

Now, the next problem that lies before us—and it
is an extremely important one—is this: Does this
selective breeding occur in nature? Because, if there
is no proof of it, all that I have been telling you
goes for nothing in accounting for the origin of
species. Are natural causes competent to play the
part of selection in perpetuating varieties? Here
we labour under very great difficulties. In the
last lecture I had occasion to point out to you the
extreme difficulty of obtaining evidence even of the
first origin of those varieties which we know to have
occurred in domesticated animals. I told you, that
almost always* the origin of these varieties is over-
looked, so that I could only produce two or three cases,
as that of Gratio Kelleia and of the Ancon sheep.
People forget, or do not take notice of them until
they come to have a prominence; and if that is true
of artificial,cases, under our own eyes, and in animals
in our own care, how much more difficult it must be to
have at first hand good evidence of the origin of varieties

118 CONDITIONS AFFECTING THE

in nature! Indeed, I do not know that it is possible
by direct evidence to prove the origin of a variety in
nature, or to prove selective breeding; but I will tell
you what we can prove—and this comes to the same
thing—that varieties exist in nature within the limits
of species, and, what is more, that when a variety has
come into existence in nature, there are natural causes
and conditions, which are amply competent to play
the part of a selective breeder; and although that is
not quite the evidence that one would like to have—
though it is not direct testimony—yet it is exceeding
good and exceedingly powerful evidence in its way.

As to the first point, of varieties existing among natural
species, I might appeal to the universal experience of
every naturalist, and of any person who has ever turned
any attention at all to the characteristics of plants and
animals in a state of nature; but I may as well take
a few definite cases, and I will begin with Man himself.

I am one of those who believe that, at present, there
is no evidence whatever for saying, that mankind
sprang originally from any more than a single pair ;
I must say, that I cannot see any good ground
whatever, or even any tenable sort of evidence, for
believing that there is more than one species of Man.
Nevertheless, as you know, just as there are numbers
of varieties in animals, so there are remarkable varie-
ties of men. I speak not merely of those broad and
distinct variations which you see at a glance. Every-
body, of course, knows the difference between a Negro
and a white man, and can tell a Chinaman from an
Englishman. They each have peculiar characteristics
of colour and physiognomy; but you must recollect

PERPETUATION OF LIVING BEINGS. 119

that the characters of these races go very far deeper
—they extend to the bony structure, and to the cha-
racters of that most important of all organs to us—the
brain; so that, among men belonging to different races,
or even within the same race, one man shall have a
brain a third, or half, or even seventy per cent. bigger
than another; and if you take the whole range of
human brains, you will find a variation in some cases
of a hundred per cent. Apart from these variations in
the size of the brain, the characters of the skull vary.
Thus if I draw the figures of a Mongul and a Negro
head on the blackboard, in the case of the last the
breadth would be about seven-tenths, and in the other
it would be nine-tenths of the total length. So that
you see there is abundant evidence of variation among
men in their natural condition. And if you turn to
other animals there is just the same thing. The fox,
for example, which has a very large geographical
distribution all over Europe, and parts of Asia, and
on the American Continent, varies greatly. There are
mostly large foxes in the North, and smaller ones in
the South. In Germany alone, the foresters reckon
some eight different sorts.

Of the tiger, no one supposes that there is more
than one species; they extend from the hottest parts of
Bengal, into the dry, cold, bitter steppes of Siberia,
into a latitude of 50°,—so that they may even prey
upon the reindeer. These tigers have exceedingly
different characteristics, but still they all keep their
general features, so that there is no doubt as to their
being tigers. The Siberian tiger has a thick fur, a
small mane, and a longitudinal stripe down the back,

120 CONDITIONS AFFECTING THE

while the tigers of Java and Sumatra differ in many
important respects from the tigers of Northern Asia.
So lions vary; so birds vary; and so, if you go further
back and lower down in creation, you find fishes vary.
In different streams, in the same country even, you will
find the trout to be quite different to each other and
easily recognizable by those who fish in the particular
streams. There is the same differences in leeches ; leech
collectors can easily point out to you the differences
and the peculiarities which you yourself would pro-
bably pass by; so with fresh-water mussels; so, in fact,
with every animal you can mention.

In plants there is the same kind of variation. Take
such a case even as the common bramble. The bota-
nists are all at war about it; some of them wanting to
make out that there are many species of it, and others
maintaining that they are but many varieties of one
species; and they cannot settle to this day which is a
species and which is a variety !

So that there can be no doubt whatsoever that any
plant and any animal may vary in nature; that varieties
may arise in the way I have described,—as spontaneous
varieties,—and that those varieties may be perpetuated
in the same way that I have shown you spontaneous
varieties are perpetuated; I say, therefore, that there
can be no doubt“as to the origin and perpetuation of
varieties in nature.

But the question now is:— Does selection take
place in nature? is there anything like the operation
of man in exercising selective breeding, taking place
in nature? You will observe that, at present, I say
nothing about species; I wish to confine myself to the

PERPETUATION OF LIVING BEINGS. 12]

consideration of the production of those natural races
which everybody admits to exist. The question is,
whether in nature there are causes competent to pro-
duce races, just in the same way as man is able to
produce, by selection, such races of animals as we have
already noticed.

When a variety has arisen, the Conpitions or Extst-
ENCE are such as to exercise an influence which is
exactly comparable to that of artificial selection. By
Conditions of Existence I mean two things, — there
are conditions which are furnished by the physical, the
inorganic world, and there are conditions of existence
which are furnished by the organic world. ‘There is,
in the first place, Crimare; under that head I include
only temperature and the varied amount of moisture of
particular places. In the next place there is what is
technically called Station, which means — given the
climate, the particular kind of place in which an ani-
mal or a plant lives or grows; for example, the station
of a fish is in the water, of a fresh-water fish in fresh
water; the station of a marine fish is in the sea, and a
marine animal may have a station higher or deeper.
So again with land animals: the differences in their
stations are those of different soils and neighbour-
hoods; some being best adapted to a calcareous, and
others to an arenaceous soil. The third condition of
existence is Foop, by which I mean food in the
broadest sense, the supply of the materials necessary to
the existence of an organic being; in the case of a
plant the inorganic matters, such as carbonic acid,
water, ammonia, and the earthy salts or salines; in the
case of the animal the inorganic and organic matters,

122 CONDITIONS AFFECTING THE

which we have seen they require ; then these are all, at
least the two first, what we may call the inorganic or
physical conditions of existence. Food takes a mid-
place, and then come the organic conditions ; by which
I mean the conditions which depend upon the state of
the rest of the organic creation, upon the number and
kind of living beings, with which an animal is sur-
rounded. You may class these under two heads: there
are organic beings, which operate as opponents, and:
there are organic beings which operate as helpers to
any given organic creature. The opponents may be of
two kinds: there are the indirect opponents, which are
what we may call rivals ; and there are the direct oppo-
nents, those which strive to destroy the creature; and
these we call enemies. By rivals I mean, of course, in
the case of plants, those which require for their sup--
port the same kind of soil and station, and, among
animals, those which require the same kind of station,
or food, or climate; those are the indirect opponents ;
the direct opponents are, of course, those which prey
upon an animalor vegetable. The helpers may also be
regarded as direct and indirect : in the case of a carnivo-
rous animal, for example, a particular herbaceous plant
may in multiplying be an indirect helper, by enabling
the herbivora on which the carnivore preys to get more
food, and thus to nourish the carnivore more abun-
dantly ; the direct helper may be best illustrated by
reference to some parasitic creature, such as the tape-
worm. The tape-worm exists in the human intestines,
so that the fewer there are of men the fewer there will
be of tape-worms, other things being alike. It is a
humiliating reflection, perhaps, that we may be classed ~

PERPETUATION OF LIVING BEINGS. 123

as direct helpers to the tape-worm, but the fact is so:
we can all see that if there were no men there would
be no tape-worms.

It is extremely difficult to estimate, in a proper way,
the importance and the working of the Conditions of
Existence. I do not think there were any of us who
had the remotest notion of properly estimating them
‘until the publication of Mr. Darwin’s work, which
has placed them before us with remarkable clearness ;
and I must endeavour, as far as I can in my own
fashion, to give you some notion of how they work.
We shall find it easiest to take a simple case, and one
-as free as possible from every kind of complication.

I will suppose, therefore, that all the habitable part
of this globe—the dry land, amounting to about
51,000,000 square miles,—I will suppose that the whole
of that dry land has the same climate, and that it is
composed of the same kind of rock or soil, so that
there will be the same station everywhere; we thus
get rid of the peculiar influence of different climates
and stations. I will then imagine that there shall be
but one organic being in the world, and that shall be a
plant. In this we start fair. Its food is to be carbonic
acid, water and ammonia, and the saline matters
in the soil, which are, by the supposition, everywhere
alike. We take one single plant, with no oppo-
nents, no helpers, and no rivals; it is to be a “fair
field, and no favour.” Now, I will ask you to imagine
further that it shall be a plant which shall produce
every year fifty seeds, which is a very moderate num-
ber for a plant to produce; and that, by the action
of the winds and currents, these seeds shall be equally

124 CONDITIONS AFFECTING THE

and gradually distributed over the whole surface of the
land. I want you now to trace out what will occur, and
you will observe that I am not talking fallaciously any
more than a mathematician does when he expounds his
problem. If you show that the conditions of your
problem are such as may actually occur in nature and
do not transgress any of the known laws of nature in
working out your proposition, then you are as safe in
the conclusion you arrive at as is the mathematician in
arriving at the solution of his problem. In science, the
only way of getting rid of the complications with which
a subject of this kind is environed, is to work in
this deductive method. What will be the result,
then ? I will suppose that every plant requires one
square foot of ground to live upon; and the result will
be that, in the course of nine years, the plant will have
occupied every single available spot in the whole globe !
I have chalked upon the blackboard the figures by
which I arrive at the result :—

Plants. Plants.

1 X 50 in Ist year = 50

bOm< bese end ee a — 2,500

2 00R ro Os OLds se 125,000

125,000 x 50 ,, 4th 4, = 6,250,000:

6,250,000 x 50 ,, 5th ,, = 312,500,000:
312,500,000 x 50 ,, 6th 4, = 15, 625,000,000
15,625,000,000 x 50 ,, 7th ,, = 781,250,000,000
781,250,000,000 x 50 ,, Sth ,, = 89,062,500,000,000
39,062,500,000,000 x 50 ,, 9th ,, = 1,953,125,000,000,000:

51,000,000 sq. miles—the dry sur- }
face of the earth X 27,878, 400— =sq.ft. 1,421,798,400,000,000

the number of sq. ft. in 1 sq. mile
being 531,326,600,000,000

square feet less than would be required at the end of the ninth year.

PERPETUATION OF LIVING BEINGS. 125

You will see from this that, at the end of the first year
the single plant will have produced fifty more of its
kind; by the end of the second year these will have
increased to 2,500; and so on, in succeeding years, you
get beyond even trillions; and I am not at all sure
that I could tell you what the proper arithmetical
denomination of the total number really is; but,
at any rate, you will understand the meaning of all
those noughts. Then you see that, at the bottom, I
have taken the 51,000,000 of square miles, constituting
the surface of the dry land; and as the number of
square feet are placed under and subtracted from the
number of seeds that would be produced in the ninth
year, you can see at once that there would be an im-
mense number more of plants than there would be
square feet of ground for their accommodation.. This is
certainly quite enough to prove my point ; that between
the eighth and ninth year after being planted the single
plant would have stocked the whole available surface of
the earth.

This is a thing which is hardly conceivable—it seems
hardly imaginable—yet it is so. It is indeed simply the
law of Malthus exemplified. Mr. Malthus was a clergy-
man, who worked out this subject most minutely and
truthfully some years ago; he showed quite clearly,—
and although he was much abused for his conclusions
at the time, they have never yet been disproved and
never will be—he showed that in consequence of the
increase in the number of organic beings in a geometrical
ratio, while the means of existence cannot be made to
increase in the same ratio, that there must come a time
when the number of organic beings will be in excess of

126 CONDITIONS AFFECTING THE

the power of production of nutriment, and that thus
some check must arise to the further inerease of those
organic beings. At the end of the ninth year we
have seen that each plant would not be able to get
its full square foot of ground, and at the end of
another year it would have to share that space with
fifty others the produce of the seeds which it would
give off.

What, then, takes place? Every plant grows up,
flourishes, occupies its square foot of ground, and gives
off its fifty seeds; but notice this, that out of this number
only one can come to anything; there is thus, as it
were, forty-nine chances to one against its growing up;
it depends upon the most fortuitous circumstances
whether any one of these fifty seeds shall grow up and
flourish, or whether it shall die and perish. This is
what Mr. Darwin has drawn attention to, and called
the “Srrueerzr rok Existence;”? and I have
taken this simple case of a plant because some
people imagine that the phrase seems to imply a sort
of fight.

T have taken this plant and shown you that this is the
result of the ratio of the increase, the necessary result
of the arrival of a time coming for every species when
exactly as many members must be destroyed as are
born ; that is the inevitable ultimate result of the rate
of production. Now, what is the result of all this? I
have said that there are forty-nine struggling against
every one; and it amounts to this, that the smallest
possible start given to any one seed may give it an
advantage which will enable it to get ahead of all the
others; anything that will enable any one of these seeds

PERPETUATION OF LIVING BEINGS. 127

to germinate six hours before any of the others will,
other things being alike, enable it to choke them out
altogether. I have shown you that there is no par-
ticular in which plants will not vary from each other ;
it is quite possible that one of our imaginary plants may
vary in such a character as the thickness of the integu-
ment of its seeds. It might happen that one of the
plants might produce seeds having a thinner integu-
ment, and that would enable the seeds of that plant
to germinate a little quicker than those of any of the
others, and those seeds would most inevitably ex-
tinguish the forty-nine times as many that were
struggling with them.

I have put it in this way, but you see the practical
result of the process is the same as if some person had
nurtured the one and destroyed the other seeds. It does
not matter how the variation is produced, so long as it is.
once allowed to occur. The variation in the plant once
fairly started tends to become hereditary and repro-
duce itself; the seeds would spread themselves in the
same way and take part in the struggle with the forty-
nine hundred, or forty-nine thousand, with which they
might be exposed. Thus, by degrees, this variety, with
some slight organic change or modification, must spread
itself over the whole surface of the habitable globe, and
extirpate or replace the other kinds. That is what is
meant by Naturax Sexzcrion ; that is the kind of argu-
ment by which it is perfectly demonstrable that the
conditions of existence may play exactly the same part
for natural varieties as man does for domesticated
varieties. No one doubts at all that particular cir-
cumstances may be more favourable for one plant

128 CONDITIONS AFFECTING THE

and less so for another, and the moment you admit
that you admit the selective power of nature. Now,
although I have been putting a hypothetical case,
you must not suppose that I have been reasoning
hypothetically. There are plenty of direct experi-
ments which bear out what we may call the theory
of natural selection; there is extremely good authority
for the statement that if you take the seed of mixed
varieties of wheat and sow it, collecting the seed next
year and sowing it again, at length you will find that
out of all your varieties only two or three have
lived, or perhaps even only one. There were one
or two varieties which were best fitted to get on,
and they have killed out the other kinds in just the
same way and with just the same certainty as if
you had taken the trouble to remove them. As I
have already said, the operation of nature is exactly
the same as the artificial operation of man.

But if this be true of that simple case, which I put
before you, where there is nothing but the rivalry of one
member of aspecies with others, what must be the opera-
tion of selective conditions, when you recollect as a matter
of fact, that for every species of animal or plant there
are fifty or a hundred species which might all, more or
less, be comprehended in the same climate, food, and
station ;—that every plant has multitudinous animals
which prey upon it, and which are its direct opponents ;
and that these have other animals preying upon them,
—that every plant has its indirect helpers in the birds
that scatter abroad its seed, and the animals that
manure it with their dung ;—I say, when these things
are considered, it seems impossible that any variation

PERPETUATION OF LIVING BEINGS. 129

which may arise in a species in nature should not tend
in some way or other either to be a little better or
worse than the previous stock; if it is a little better
it will have an advantage over and tend to extirpate
the latter in this crush and struggle; and if it is a
little worse it will itself be extirpated.

I know nothing that more appropriately ex-
presses this, than the phrase, “the struggle for exist-
ence; ”’ because it brings before your minds, in a vivid
sort of way, some of the simplest possible ciicumstances
connected with it. When a struggle is intense there
must be some who are sure to be trodden down,
crushed, and overpowered by others; and there will
be some who just manage to get through only by the
help of the slightest accident. I recollect reading an
account of the famous retreat of the French troops,
under Napoleon, from Moscow. Worn out, tired, and
dejected, they at length came to a great river over which
there was but one bridge for the passage of the vast army.
disorganized and demoralized as it was, the struggle
must certainly have been a terrible one—everyone
heeding only himself, and crushing through and
treading down his fellows. The writer of the narra-
tive, who was himself one of those who were fortunate
enough to succeed in getting over, and not among the
thousands who were left behind or forced into the
river, ascribed his escape to the fact that he saw
striding onward through the mass a great strong fellow,
—one of the French Cuirassiers, who had on a large
blue cloak—and he had enough presence of mind to
catch and retain a hold of this strong man’s cloak.
He says, “I caught hold of his cloak, and although

130 CONDITIONS AFFECTING THE

he swore at me and cut at and struck me by turns, and
at last, when he found he could not shake me off, fell
to entreating me to leave go or I should prevent him
from escaping, besides not assisting myself, I still kept
tight hold of him, and would not quit my grasp until
he had at last dragged me through.” Here you see
was a case of selective saving—if we may so term it—
depending for its success on the strength of the cloth
of the Cuirassier’s cloak. It is the same in nature;
every species has its Beresina; it has to fight its
way through and struggle with other species; and
when well nigh overpowered, it may be that the smallest
chance, something in its colour, perhaps—the minutest
circumstance—will turn the scale one way or the
other.

Suppose that by a variation of the black race it had
produced the white man at any time—you know that
the Negroes are said to believe this to have been the case,
and to imagine that Cain was the first white man, and
that we are his descendants — suppose that this had ever
happened, and that the first residence of this human
being was on the West Coast of Africa. There is
no great structural difference between the white man
and the Negro, and yet there is something so singularly
different in the constitution of the two, that the
malarias of that country, which do not hurt the black
at all, cut off and destroy the white, thus you see there
would have been a selective operation performed. If the
white man had risen in that way, he would have been
selected out and removed by means of the malaria. Now
there really is a very curious case of selection of this sort
among pigs, and it is a case of selection of colour, too.

PERPETUATION OF LIVING BEINGS. 13]

In the woods of Florida there are a great many pigs,.
and it is a very curious thing that they are all black,
every one of them. Professor Wyman was there some
years ago, and on noticing no pigs but these black
ones, he asked some of the people how it was that they
had no white pigs, and the veply was that in the
woods of Florida there was a root which they called
the Paint Root, and that if the white pigs were to
eat any of it, it had the effect of makingitheir hoofs
crack, and they died, but if the black pigs eat any of
it, it did not hurt them at all. Here was a very simple
case of natural selection. A skilful breeder could not
more carefully develope the black breed of pigs, and
weed out all the white pigs, than the Paint Root
does.

To show you how remarkably indirect may be such
natural selective agencies as I have referred to, I will
conclude by noticing a case mentioned by Mr. Darwin,
and which is certainly one of the most curious of its kind.
It is that of the Humble Bee. It has been noticed
that there are a great many more humble bees in the
neighbourhood of towns, than out in the open country ;
and the explanation of the matter is this: the humble
bees build nests, in which they store their honey and
deposit the larvae and eggs. The field mice are amaz-
ingly fond of the honey and larvze; therefore, wherever
there are plenty of field mice, as in the country, the
humble bees are kept down; but in the neighbourhood
of towns, the number of cats which prowl about the
fields eat up the field mice, and of course the more
mice they eat up the less there are to prey upon the
larvee of the bees—the cats are therefore the INDIRECT

182 CONDITIONS, ETC.

HELPERS of the bees.* Coming back a step farther we
may say that the old maids are also indirect friends of
the humble bees, and indirect enemies of the field mice,
as they keep the cats which eat up the latter! This
is an illustration somewhat beneath the dignity of the
subject, perhaps, but it occurs to me in passing, and
with it I will conclude this lecture.

* The humble bees, on the other hand, are direct helpers of some
plants, such as the heartsease and red clover, which are fertilized by
the visits of the bees; and they are indirect helpers of the numerous
insects which are more or less completely supported by the hearts-
ease and red clover.

LE CE URE &,

A CRITICAL EXAMINATION OF THE POSI-
TION OF MR. DARWIN’S WORK, “ON
THE ORIGIN OF SPECIES,” IN RELATION
TO THE COMPLETE THEORY OF THE
CAUSES OF THE PHENOMENA OF OR-
GANIC NATURE.

In the preceding five lectures I have endeavoured to
give you an account of those facts, and of those reason-
ings from facts, which form the data upon which all
theories regarding the causes of the phenomena of
organic nature must be based. And, although I have
had frequent occasion to quote Mr. Darwin—as all
persons hereafter, in speaking upon these subjects, will
have occasion to quote his famous book on the “ Origin
of Species,’—you must yet remember that, wherever I
have quoted him, it has not been upon theoretical
points, or for statements in any way connected with his
particular speculations, but on matters of fact, brought
forward by himself, or collected by himself, and which
appear incidentally in his book. If a man will make a
book, professing to discuss a single question, an ency-
clopzedia, I cannot help it.

Now, having had an opportunity of considering in
this sort of way the different statements bearing upon

G

134 MR. DARWIN’S WORK AND

all theories whatsoever, I have to-night to lay before
you, as fairly as I can, what is Mr. Darwin’s view of the
matter and what position his theories hold, when judged
by the principles which I have previously laid down,
as deciding our judgments upon all theories and hy-
potheses.

Thave already stated to you that the inquiry respecting
the causes of the phenomena of organic nature resolves
itself into two problems—the first being the question
of the origination of living or organic beings; and the
second being the totally distinct problem of the modi-
fication and perpetuation of organic beings when they
have already come into existence. The first question
Mr. Darwin does not touch; he does not deal with it
at all; but he says—given the origin of organic matter
—supposing its creation to have already taken place,
my object is to show in consequence of what laws and
what demonstrable properties of organic matter, and of
its environments, such states of organic nature as those
with which we are acquainted must have come about.
This, you will observe, is a perfectly legitimate proposi-
tion ; every person has a right to define the limits of the
inquiry which he sets before himself; and yet it is a
most singular thing that in all the multifarious, and,
not unfrequently, ignorant attacks which have been
made upon the “ Origin of Species,” there is nothing
which has been more speciously criticised than this
particular limitation. If people have nothing else to
urge against the book, they say—‘ Well, after all, you
see Mr. Darwin’s explanation of the ‘Origin of Species’
is not good for much, because, in the long run, he
admits that he does not know how organic matter

THE PHENOMENA OF ORGANIC NATURE. 135

began to exist. But if you admit any special creation
for the first particle of organic matter you may just as
well admit it for all the rest; five hundred or five thou-
sand distinct creations are just as intelligible, and just
as little difficult to understand, asone.” The answer to
these cavils is two-fold. In the first place, all human
inquiry must stop somewhere; all our knowledge and
all our investigation cannot take us beyond the limits
set by the finite and restricted character of our facul-
ties, or destroy the endless unknown, which accom-
panies, like its shadow, the endless procession of
phenomena. So far as I can venture to offer an
opinion on such a matter, the purpose of our being in
existence, the highest object that human beings can
set before themselves, is not the pursuit of any such
chimera as the annihilation of the unknown ; but it is
simply the unwearied endeavour to remove its boun-
daries a little further from our little sphere of action.
I wonder if any historian would for a moment admit
the objection, that it is preposterous to trouble ourselves
about the history of the Roman Empire, because we
do not know anything positive about the origin and
first building of the city of Rome! Would it bea
fair objection to urge, respecting the sublime dis-
eoveries of a Newton, or a Kepler, those great philoso-
phers, whose discoveries have been of the profoundest
benefit and service to all men,—to say to them—“ After
all that you have told us as to how the planets revolve,
and how they are maintained in their orbits, you
cannot tell us what is the cause of the origin of the
sun, moon, and stars. So what is the use of what you
have done?” Yet these objections would not be one
G2

136 MR. DARWIN’S WORK AND

whit more preposterous than the objections which have
been made to the “ Origin of Species.” Mr. Darwin,
then, had a perfect right to limit his inquiry as he
pleased, and the only question for us—the inquiry
being so limited—is to ascertain whether the method
of his inquiry is sound or unsound; whether he has
obeyed the canons which must guide and govern _all
investigation, or whether he has broken them; and it was
because our inquiry this evening is essentially limited
to that question, that I spent a good deal of time in a
former lecture (which, perhaps some of you thought
might have been better employed) in endeavouring to
illustrate the method and nature of scientific inquiry
in general. We shall now have to put in practice the
principles that I then laid down.

I stated to you in substance, if not in words, that
wherever there are complex masses of phenomena to
be inquired into, whether they be phenomena of the
affairs of daily life, or whether they belong to the more
abstruse and difficult problems laid before the philo-
sopher, our course of proceeding in unravelling that com-
plex chain of phenomena with a view to get at its cause,
is always the same; in all cases we must invent a hypo-
thesis; we must place before ourselves some more or
less likely supposition respecting that cause ; and then,
having assumed a hypothesis, having supposed a cause
for the phenomena in question, we must endeavour, on
the one hand, to demonstrate our hypothesis, or, on
the other, to upset and reject it altogether, by testing it
in three ways. We must, in the first place, be pre-
pared to prove that the supposed causes of the pheno-
mena exist in nature; that they are what the logicians

THE PHENOMENA OF ORGANIC NATURE. 137

call vera cause—true causes;—in the next place, we
should be prepared to show that the assumed causes of
the phenomena are competent to produce such pheno-
mena as those which we wish to explain by them; and
in the last place, we ought to be able to show that no
other known causes are competent to produce these
phenomena. If we can succeed in satisfying these
three conditions we shall have demonstrated our hypo-
thesis; or rather I ought to say, we shall have proved
it as far as certainty is possible for us; for, after all,
there is no one of our surest convictions which may not
be upset, or at any rate modified by a further accession
of knowledge. It was because it satisfied these con-
ditions that we accepted the hypothesis as to the dis-
appearance of the tea-pot and spoons in the case I
supposed in a previous lecture; we found that our
hypothesis on that subject was tenable and valid,
because the supposed cause existed in nature, because
it was competent to account for the phenomena, and
because no other known cause was competent to ac-
count for them; and it is upon similar grounds that
any hypothesis you choose to name is accepted in
science as tenable and valid.

What is Mr. Darwin’s hypothesis? As I apprehend
it—for I have put it into a shape more convenient for
common purposes than I could find verbatim in his
book—as I apprehend it, I say, it is, that all the phe-
nomena of organic nature, past and present, result
from, or are caused by, the inter-action of those pro-
perties of organic matter, which we have called
Atavism and VaRIaBILITy, with the ConpiTIons oF
ExIsTENCE; or, in other words,—given the existence of

138 MR. DARWIN’S WORK AND

organic matter, its tendency to transmit its properties,
and its tendency occasionally to vary ; and, lastly, given
the conditions of existence by which organic matter is
surrounded—that these put together are the causes of
the Present and of the Past conditions of Orcanic
Nature.

Such is the hypothesis as I understand it. Now let
us see how it will stand the various tests which I laid
down just now. In the first place, do these supposed
causes of the phenomena exist in nature? Is it the
fact that in nature these properties of organic matter
—atavism and variability—and those phenomena
which we have called the conditions of existence,—is it
true that they exist? Well, of course, if they do not
exist, all that I have told you in the last three or
four lectures must be incorrect, because I have been
attempting to prove that they do exist, and I take it
that there is abundant evidence that they do exist; so
far, therefore, the hypothesis does not break down, |

But in the next place comes a much more difficult
inquiry :—Are the causes indicated competent to give
rise to the phenomena of organic nature? I suspect
that this is indubitable to a certain extent. It is de-
monstrable, I think; as I have endeavoured to show
you, that they are perfectly competent to give rise to
all the phenomena which are exhibited by Raczs.in
nature. Furthermore, I believe that they are quite
competent to account for all that we may call purely
structural phenomena which are exhibited by Species
in nature. On that point also I have already enlarged
somewhat. Again, I think that the causes assumed
are competent to account for most of the physio-

THE PHENOMENA OF ORGANIC NATURE. 139

logical characteristics of species, and I not only think
that they are competent to account for them, but I
think that they account for many things which other-
wise remain wholly unaccountable and inexplicable,
and I may say incomprehensible. For a full exposition’
of the grounds on which this conviction is based, I
must refer you to Mr. Darwin’s work; all that I can
do now is to illustrate what I have said by two or three
cases taken almost at random.

I drew your attention, on a previous evening, to the
facts which are embodied in our systems of Classifi-
cation, which are the results of the examination and
comparison of the different members of the animal
kingdom one with another. I mentioned that the
whole of the animal kingdom is divisible into five sub-
kingdoms; that each of these sub-kingdoms is again
divisible into provinces; that each province may be
divided into classes, and the classes into the succes-
sively smaller groups, orders, families, genera, and
species.

Now, in each of these groups, the resemblance in
structure among the members of the group is closer in
proportion as the group is smaller. Thus, a man and
a worm are members of the animal kingdom in virtue
of certain apparently slight though really fundamental
resemblances which they present. But a man and a
fish are members of the same Sub-kingdom Vertebrata,
because they are much more like one another than
either of them is to a worm, or a snail, or any member
of the other sub-kingdoms. For similar reasons men
and horses are arranged as members of the same Class,
Mammalia; men and apes as members of the same

°

140 MR. DARWIN’S WORK AND

Order, Primates; and if there were any animals more
like men than they were like any of the apes, and yet
different from men in important and constant particu-
lars of their organization, we should rank them as
members of the same. Family, or of the same Genus,
but as of distinct Species.

That it is possible to arrange all the varied forms of
animals into groups, having this sort of singular subor-
dination one to the other, is a very remarkable cireum-
stance; but, as Mr. Darwin remarks, this is a result
which is quite to be expected, if the principles which he
lays down be correct. Take the case of the races which
are known to be produced by the operation of atavism

and variability, and the conditions of existence which

check and modify these tendencies. Take the case of the
pigeons that I brought before you: there it was shown
that they might be all classed as belonging to some one
of five principal divisions, and that within these divisions
other subordinate groups might be formed. The mem-
bers of these groups are related to one another in just
the same way as the genera of a family, and the groups
themselves as the families of an order, or the orders of
a class; while all have the same sort of structural rela-
tions with the wild Rock-pigeon, as the members of any
great natural group have with a real or imaginary
typical form. Now, we know that all varieties of
pigeons of every kind have arisen by a process of
selective breeding from a common stock, the Rock-
pigeon ; hence, you see, that if all species of animals
have proceeded from some common stock, the general
character of their structural relations, and of our sys-
tems of classification, which express those relations,

THE PHENOMENA OF ORGANIC NATURE. 141

would be just what we find them to be. In other
words, the hypothetical cause is, so far, competent to
produce effects similar to those of the real cause.

Take, again, another set of very remarkable facts,—
the existence of what are called rudimentary organs,
organs for which we can find no obvious use, in the
particular animal economy in which they are found,
and yet which are there.

Such are the splint-like bones in the leg of the
horse, which I here show you, and which correspond
with bones which belong to certain toes and fingers
in the human hand and foot. Jn the horse you see
they are quite rudimentary, and bear neither toes nor
fingers; so that the horse has only one “ finger”? in
his fore-foot and one “toe” in his hind-foot. But
it is a very curious thing that the animals closely
allied to the horse show more toes than he; as the
rhinoceros, for instance: he has these extra toes well
formed, and anatomical facts show very clearly that he
is very closely related to the horse indeed. So we
may say that animals, in an anatomical sense nearly
related to the horse, have those parts which are rudi-
mentary in him, fully developed.

Again, the sheep and the cow have no cutting-teeth,
but only a hard pad in the upper jaw. That is
the common characteristic of ruminants in general.
But the calf has in its upper jaw some rudiments of
teeth which never are developed, and never play the
part of teeth at all. Well, if you go back in time, you
find some of the older, now extinct, allies of the rumi-
nants have well-developed teeth in their upper jaws ;
and at the present day the pig (which is in structure

142 MR. DARWIN’S WORK AND

closely connected with ruminants) has well-developed
teeth in its upper jaw; so that here is another in-
stance of organs well developed and very useful, in one
animal, represented by rudimentary organs, for which we
can discover no purpose whatsoever, in another closely
allied animal. The whalebone whale, again, has horny
“ whalebone ” plates in its mouth, and no teeth; but
the young foetal whale, before it is born, has teeth in
its jaws; they, however, are never used, and they never
come to anything. But other members of the group to
which the whale belongs have well-developed teeth in
both jaws.

Upon any hypothesis of special creation, facts of this
kind appear to me to be entirely unaccountable and
inexplicable, but they cease to be so if you accept
Mr. Darwin’s hypothesis, and see reason for believing
that the whalebone whale and the whale with teeth in
its mouth both sprang from a whale that had teeth,
and that the teeth of the foetal whale are merely rem-
nants—recollections, if we may so say—of the extinct
whale. So in the case of the horse and the rhino-
ceros: suppose that both have descended by modification
from some earlier form which had the normal number
of toes, and the persistence of the rudimentary bones
which no longer support toes in the horse becomes
comprehensible.

In the language that we speak in England, and in
the language of the Greeks, there are identical verbal
roots, or elements entering into the composition of
words. That fact remains unintelligible so long as we
suppose English and Greek to be independently created
tongues ; but when it is shown that both languages are

THE PHENOMENA OF ORGANIC NATURE. 143

descended from one original, the Sanscrit, we give an
explanation of that resemblance. In the same way the
existence of identical structural roots, if I may so term
them, entering into the composition of widely different
animals, is striking evidence m favour of the descent
of those animals from a common original.

To turn to another kind of illustration: —If you
regard the whole series of stratified rocks—that enor-
mous thickness of sixty or seventy thousand feet that
I have mentioned before, constituting the only record
we have of a most prodigious lapse of time, that
time being, in all probability, but a fraction of that of
which we have no record; — if you observe in these
successive strata of rocks successive groups of animals
arising and dying out, a constant succession, giving you
the same kind of impression, as you travel from one
group of strata to another, as you would have in travel-
ling from one country to another ;—when you find this
constant succession of forms, their traces obliterated
except to the man of science,—when you look at this
wonderfal history, and ask what it means, it is only a
paltering with words if you are offered the reply,—
«They were so created.”

But if, on the other hand, you look on all forms of
organized beings as the results of the gradual modifi-
cation of a primitive type, the facts receive a meaning,
and you see that these older conditions are the neces-
sary predecessors of the present. Viewed in this light
the facts of palzeontology receive a meaning—upon any
other hypothesis, I am unable to see, in the slightest
degree, what knowledge or signification we are to draw
out of them. Again, note as bearing upon the same

144 MR. DARWIN’S WORK AND

point, the singular likeness which obtains between the
successive Faun and Flore, whose remains are pre-
served on the rocks: you never find any great and
enormous difference between the immediately succes-
sive Faune and Flore, unless you have reason to
believe there has also been a great lapse of time ora
great change of conditions. The animals, for instance,
of the newest tertiary rocks, in any part of the world,
are always, and without exception, found to be closely
allied with those which now live in that part of the
world. For example, in Europe, Asia, and Africa,
the large mammals are at present rhinoceroses,
hippopotamuses, elephants, lions, tigers, oxen, horses,
&c.; and if you examine the newest tertiary deposits,
which contain the animals and plants which im-
mediately preceded those which now exist in the
same country, you do not find gigantic specimens of
ant-eaters and kangaroos, but you find rhinoceroses,
elephants, lions, tigers, &c.,—of different species to
those now living,—but still their close allies. If you
turn to South America, where, at the present day,
we have great sloths and armadilloes and creatures of
that kind, what do you find in the newest tertiaries ?
You find the great sloth-like creature, the Megatheriun,
and the great armadillo, the Glyptodon, and so on. And
if you go to Australia you find the same law holds
good, namely, that that condition of organic nature
which has preceded the one which now exists, pre-
sents differences perhaps of species, and of genera, but
that the great types of organic structure are the same
as those which now flourish.

What meaning has this fact upon any other hypo-

THE PHENOMENA OF ORGANIC NATURE. 145

thesis or supposition than one of successive modifica-
tion? But if the population of the world, in any age,
is the result of the gradual modification of the forms
which peopled it in the preceding age,—if that has been
the case, it is intelligible enough; because we may
expect that the creature that results from the modifi-
cation of an elephantine mammal shall be something
like an elephant, and the creature which is produced by
the modification of an armadillo-like mammal shall be
like an armadillo. Upon that supposition, I say, the
facts are intelligible; upon any other, that I am aware
of, they are not.

So far, the facts of paleontology are consistent with
almost any form of the doctrine of progressive modifi-
cation; they would not be absolutely inconsistent with
the wild speculations of De Maillet, or with the less
objectionable hypothesis of Lamarck. But Mr. Dar-
-win’s views have one peculiar merit; and that is, that
they are perfectly consistent with an array of facts which
are utterly inconsistent with and fatal to, any other
hypothesis of progressive modification which has yet
been advanced. It is one remarkable peculiarity of
Mr. Darwin’s hypothesis that it involves no necessary
progression or incessant modification, and that it is
perfectly consistent with the persistence for any length
of time of a given primitive stock, contemporaneously
with its modifications. To return to the case of the
domestic breeds of pigeons, for example; you have the
Dove-cot pigeon, which closely resembles the Rock
pigeon, from which they all started, existing at the
same time with the others. And if species are de-
veloped in the same way in nature, a primitive stock

146 MR. DARWIN’S WORK AND

and its modifications may, occasionally, all find the
conditions fitted for their existence ; and though they
come into competition, to a certain extent, with one
another, the derivative species may not necessarily
extirpate the primitive one, or vice versd.

Now palzontology shows us many facts which are
perfectly harmonious with these observed effects of the
process by which Mr. Darwin supposes species to have
originated, but which appear to me to be totally
inconsistent with any other hypothesis which has been
proposed. There are some groups of animals and
plants, in the fossil world, which have been said to
belong to “ persistent types,” because they have per-
sisted, with very little change indeed, through a very
great range of time, while everything about them has
changed largely. There are families of fishes whose
type of construction has persisted all the way from the
carboniferous rock right up to the cretaceous; and
others which have lasted through almost the whole
range of the secondary rocks, and from the lias
to the older tertiaries. It is something stupendous this
—to consider a genus lasting without essential modi-
fications through all this enormous lapse of time while
almost everything else was changed and modified.

Thus I have no doubt that Mr. Darwin’s hypothesis
will be found competent to explain the majority of
the phenomena exhibited by species in nature; but in
an earlier lecture I spoke cautiously with respect to its
power of explaining all the physiological peculiarities
of species.

There is, in fact, one set of these peculiarities which the
theory of selective modification, as it stands at present,

THE PHENOMENA OF ORGANIC NATURE, 147

is not wholly competent to explain, and that is the group
of phenomena which I mentioned to you under the name
of Hybridism, and which I explained to consist in the
sterility of the offspring of certain species when crossed
one with another. It matters not one whit whether
this sterility is universal, or whether it exists only in a
single case. Every hypothesis is bound to explain, or,
at any rate, not be inconsistent with, the whole of the
facts which it professes to account. for; and if there is
a single one of these facts which can be shown to be
inconsistent with (I do not merely mean inexplicable
by, but contrary to,) the hypothesis, the hypothesis
falls to the ground,—it is worth nothing. One fact
with which it is positively inconsistent is worth as
much, and as powerful in negativing the hypothesis,
as five hundred. If I am right in thus defining the
obligations of a hypothesis, Mr. Darwin, in order to
place his views beyond the reach of all possible assault,
ought to be able to demonstrate the possibility of deve-
loping from a particular stock, by selective breeding,
two forms, which should either be unable to cross one
with another, or whose cross-bred offspring should be
infertile with one another.

For, you see, if you have not done that you have not
strictly fulfilled all the conditions of the problem ; you
have not shown that you can produce, by the cause
assumed, all the phenomena which you have in nature.
Here are the phenomena of Hybridism staring you in
the face, and you cannot say, “I can, by selective
modification, produce these same results.” Now, it is
admitted on all hands that, at present, so far as experi-
ments have gone, it has.not been found possible to pro-

148 MR. DARWIN’S WORK AND

duce this complete physiological divergence by selective
breeding. I stated this very clearly before, and I now
refer to the point, because, if it could be proved, not
only that this has not been done, but that it cannot be
done; if it could be demonstrated that it is impossible
to breed selectively, from any stock, a form which shall
not breed with another, produced from the same stock ;
and if we were shown that this must be the necessary
and inevitable result of all experiments, I hold that
Mr. Darwin’s hypothesis would be utterly shattered.

But has this been done? or what is really the state
of the case? It is simply that, so far as we have gone
yet with our breeding, we have not produced from a
common stock two breeds which are not more or less
fertile with one another.

I do not know that there is a single fact which would
justify any one in saying that any degree of sterility has
been observed between breeds absolutely known to have
been produced by selective breeding from a common
stock. On the other hand, 1 do not know that there
is a single fact which can justify any one in asserting
that such sterility cannot be produced by proper
experimentation. For my own part, I see every reason
to believe that it may, and will be so produced. For,
as Mr. Darwin has very properly urged, when we
consider the phenomena of sterility, we find they are
most capricious; we do not know what it is that
the sterility depends on. ‘There are some animals
which will not breed in captivity; whether it arises
from the simple fact of their being shut up and
deprived of their liberty, or not, we do not know, but
they certainly will not breed. What an astounding

THE PHENOMENA OF ORGANIC NATURE. 149

thing this is, to find one of the most important of all
functions annihilated by mere imprisonment !

So, again, there are cases known of animals which
have been thought by naturalists to be undoubted
species, which have yielded perfectly fertile hybrids ;
while there are other species which present what every-
body believes to be varieties * which are more or less
infertile with one another. There are other cases which
are truly extraordinary; there is one, for example,
which has been carefully examined,—cf two kinds of
sea-weed, of which the male element of the one, which
we may call A, fertilizes the female element of the
other, B; while the male element of B will not fer-
tilize the female element of A; so that, while the
former experiment seems to show us that they are
varicties, the latter leads to the conviction that they
are species.

When we see how capricious and uncertain this
sterility is, how unknown the conditions on which it
depends, I say that we have no right to affirm that
those conditions will not be better understood by and
by, and we have no ground for supposing that we may
not be able to experiment so as to obtain that crucial
result which I mentioned just now. So that though
Mr. Darwin’s hypothesis does not completely extricate
us from this difficulty at present, we have not the least
right to say it will not do so.

There is a wide gulf between the thing you cannot

* And as I conceive with very good reason; but if any objector
urges that we cannot prove that they have been produced by arti-
ficial or natural selection, the objection must be admitted—ultra-
sceptical as it is. But in science, scepticism is a duty,

150 MR. DARWIN’S WORK AND

explain and the thing that upsets you altogether.
There is hardly any hypothesis in this world which
has not some fact in connection with it which has not
been explained, but that is a very different affair to a
fact that entirely opposes your hypothesis ; in this case
all you can say is, that your hypothesis is in the same
position as a good many others.

Now, as to the third test, that there are no other
causes competent to explain the phenomena, I explained
to you that one should be able to say of a hypothesis,
that no other known causes than those supposed by it
are competent to give rise to the phenomena. Here,
I thmk, Mr. Darwin’s view is pretty strong. I really
believe that the alternative is either Darwinism or
nothing, for I do not know of any rational conception
or theory of the organic universe which has any
scientific position at all beside Mr. Darwin’s. I do
not know of any proposition that has been put before
us with the intention of explaining the phenomena
of organic nature, which has in its favour a thousandth
part of the evidence which may be adduced in favour
of Mr. Darwin’s views. Whatever may be the ob-
jections to his views, certainly all others are absolutely
out of court.

Take the Lamarckian hypothesis, for example.
Lamarck was a great naturalist, and to a certain
extent went the right way to work; he argued from
what was undoubtedly a true cause of some of
the phenomena of organic nature. He said it is a
matter of experience that an animal may be modified
more or less in consequence of its desires and conse-
quent actions. Thus, if a man exercise himself as a

THE PHENOMENA OF ORGANIC NATURE. Sy

blacksmith, his arms will become strong and muscular;
such organic modification is a result of this particular
action and exercise. Lamarck thought that by a very
simple supposition based on this truth he could explain
the origin of the various animal species: he said, for
example, that the short-legged birds which live on
fish, had been converted into the long-legged waders
by desiring to get the fish without wetting their feet,
and so stretching their legs more and more through
successive generations. If Lamarck could have shown
experimentally, that even races of animals could be pro-
duced in this way, there might have been some ground
for his speculations. But he could show nothing of the
kind, and his hypothesis has pretty well dropped into
oblivion, as it deserved to do. I said in an earlier
lecture that there are hypotheses and hypotheses, and
when people tell you that Mr. Darwin’s strongly-
' based hypothesis is nothing but a mere modification
of Lamarck’s, you will know what to think of their
capacity for forming a judgment on this subject.
But you must recollect that when I sayI think it
is either Mr. Darwin’s hypothesis or nothing; that

-

~ either we must take his view, or look upon the whole of
organic nature as an enigma, the meaning of which
is wholly hidden from us; you must understand that I
mean that I accept it provisionally, in exactly the same
way as I accept any other hypothesis. Men of science
do not pledge themselves to creeds; they are bound by
articles of no sort; there is not a single belief that it
is not a bounden duty with them to hold with a light
hand and to part with it, cheerfully, the moment it is
really proved to be contrary to any fact, great or small.

152 MR. DARWIN’S WORK AND

And if in course of time I see good reasons for such a
proceeding, I shall have no hesitation in coming before
you, and pointing out any change in my opinion without
finding the slightest occasion to blush for so doing. So
I say that we accept this view as we accept any other,
so long as it will help us, and we feel bound to retain it
only so long as it will serve our great purpose—the
improvement of Man’s estate and the widening of his
knowledge. The moment this, or any other conception,
ceases to be useful for these purposes, away with it to
the four winds; we care not what becomes of it!

But to say truth, although it has been my business
to attend closely to the controversies roused by the
publication of Mr. Darwin’s book, I think that not one
of the enormous mass of objections and obstacles which
have been raised is of any very great value, except that
sterility case which I brought before you just now. All
the rest are misunderstandings of some sort, arising
either from prejudice, or want of knowledge, or still
more from want of patience and care in reading the
work.

For you must recollect that it is not a book to be
read, with as much ease, as its pleasant style may lead
you toimagine. You spin through it as if it were a
novel the first time you read it, and think you know all
about it; the second time you read it you think you
know rather less about it; and the third time, you are
amazed to find how little you have really apprehended its
vast scope and objects. I can positively say that I never
take it up without finding in it some new view, or light,
or suggestion that I have not noticed before. That is
the best characteristic of a thorough and profound book ;

THE PHENOMENA OF ORGANIC NATURE. 153

and I believe this feature of the “ Origin of Species”
explains why so many persons have ventured to pass
judgment and criticisms upon it which are by no means
worth the paper they are written on.

Before concluding these lectures there is one point
to which I must advert,—though, as Mr. Darwin has
said nothing about man in his book, it concerns myself
rather than him ;—for I have strongly maintained on
sundry occasions that if Mr. Darwin’s views are sound,
they apply as much to man as to the lower mammals,
seeing that it is perfectly demonstrable that the struc-
tural differences which separate man from the apes are
not greater than those which separate some apes from
others. There cannot be the slightest doubt in the
world that the argument which applies to the improve-
ment of the horse from an earlier stock, or of ape from
ape, applies to the improvement of man from some
simpler and lower stock than man. There is not a

single faculty—functional or structural, moral, intel-

lectual, or instinctive,—there is no faculty whatever
that is not capable of improvement ; there is no faculty
whatsoever which does not depend upon structure, and
as structure tends to vary, it is capable of being im-
proved.

Well, I have taken a good deal of pains at various
times to prove this, and I have endeavoured to meet
the objections of those who maintain, that the structural
differences between man and the lower animals are of
so vast a character and enormous extent, that even if
Mr. Darwin’s views are correct, you cannot imagine
this particular modification to take place. It is, in fact,
easy matter to prove that, so far as structure is cor-

154 MR. DARWIN’S WORK AND

cerned, man differs to no greater extent from the ani-
mals which are immediately below him than these do
from other members of the same order. Upon the
other hand, there is no one who estimates more highly
than I do the dignity of human nature, and the width
of the gulf in intellectual and moral matters, which lies
between man and the whole of the lower creation.

But I find this very argument brought forward vehe-
mently by some. ‘* You say that man has proceeded
from a modification of some lower animal, and you take
pains to prove that the structural differences which are
said to exist in his brain do not exist at all, and you
teach that all functions, intellectual, moral, and others,
are the expression or the result, in the long run, of
structures, and of the molecular forces which they
exert.” It is quite true that I do so.

“Well, but,” I am told at once, somewhat triumph-
antly, ‘you say in the same breath that there is a great
moral and intellectual chasm between man and the
lower animals. How is this possible when you declare
that moral and intellectual characteristics depend on
structure, and yet tell us that there is no such gulf
between the structure of man and that of the lower
animals ?”

I think that objection is based upon a misconception
of the real relations which exist between structure and
function, between mechanism and work. Function is
the expression of molecular forces and arrangements
no doubt; but, does it follow from this, that variation in
function so depends upon variation in structure that
the former is always exactly proportioned to the latter?
If there is no such relation, if the variation in function

THE PHENOMENA OF ORGANIC NATURE. 15

Or

which follows on a variation in structure, may be enor-
mously greater than the variation of the structure, then,
you see, the objection falls to the ground.

Take a couple of watches—made by the same maker,
and as completely alike as possible; set them upon the
table, and the function of each—which is its rate of going
—will be performed in the same manner, and you shall
be able to distinguish no difference between them ; but
let me take a pair of pincers, and if my hand is steady
enough to do it, let me just lightly crush together the
bearings of the balance-wheel, or force to a slightly
different angle the teeth of the escapement of one of
them, and of course you know the immediate result
will be that the watch, so treated, from that moment
will cease to go. But what proportion is there between
the structural alteration and the functional result? Is
it not perfectly obvious that the alteration is of the
minutest kind, yet that slight as it is, it has produced
an infinite difference in the performance of the functions
of these two instruments ?

Well, now, apply that to the present question. What
is it that constitutes and makes man what he is?
What is it but his power of language—that language
giving him the means of recording his experience—
making every generation somewhat wiser than its
predecessor,—more in accordance with the established
order of the universe ?

_ What is it but this power of speech, of recording
experience, which enables men to be men—looking
before and after and, in some dim sense, understanding
the working of this wondrous universe—and which
distinguishes man from the whole of the brute world?

156 MR. DARWIN’S WORK AND

I say that this functional difference is vast, unfathom-
able, and truly infinite in its consequences; and I say
at the same time, that it may depend upon structural
differences which shall be absolutely inappreciable to
us with our present means of investigation. What
is this very speech that we are talking about? Iam
speaking to you at this moment, but if you were to alter,
in the minutest degree, the proportion of the nervous
forces now active in the two nerves which supply the
muscles of my glottis, I should become suddenly dumb.
The voice is produced only so long as the vocal chords
are parallel; and these are parallel only so long as
certain muscles contract with exact equality ; and that
again depends on the equality of action of those two
nerves I spoke of. So that a change of the minutest
kind in the structure of one of these nerves, or in
the structure of the part in which it originates,
or of the supply of blood to that part, or of one
of the muscles to which it is distributed, might
render all of us dumb. But a race of dumb men,
deprived of all communication with those who could
speak, would be little indeed removed from the brutes.
And the moral and intellectual difference between
them and ourselves would be practically infinite,
though the naturalist should not be able to find a
single shadow of even specific structural difference.
But let me dismiss this question now, and, in conclu-
sion, let me say that you may go away with it as
my mature conviction, that Mr. Darwin’s work is the
greatest contribution which has been made to bio-
logical science since the publication of the “ Régne
Animal” of Cuvier, and since that of the “ History of

THE PHENOMENA OF ORGANIC NATURE. 157

Development,” of Von Baer. I believe that if you
strip it of its theoretical part it still remains one of the
greatest encyclopedias of biological doctrine that any
one man ever brought forth; and I believe that, if
you take it as the embodiment of a hypothesis, it is
destined to be the guide of biological and psychological
speculation for the next three or four generations.

THE END.

ROBERT HARDWICKE, PRINTER, 192, PICCADILLY.

pMtee

Piss

oe gts opel -$ ofa ner,
ne

* SbRAy: O55 ot}
hits Sapte AU

ei eet an aes a ae .

mm up

=~

—— |
‘

vain

bees fe

aw G7 é

i

USEFUL WORKS

PUBLISHED BY

ROBERT HARDWICKE,

192, PICCADILLY, wW.

Third Edition, crown 8vo, price 6s.

Our Social Bees.

Pictures of Town and Country, and other Papers. By

ANDREW WyntTeER, M.D.

CONTENTS.

The Post-office.

London Smoke.

Mock Auctions.

Hyde Park.

The Suction Post.

St. George and the Dragon.

The India-rubber Artist.

Our Peck of Dirt.

The Artificial Man.

Britannia’s Smelling-bottle.

The Hunterian Museum at the
College of Surgeons.

A Chapter on Shop Windows.

Commercial Grief.

Orchards in Cheapside.

The Wedding Bonnet.

Aerated Bread.

The German Fair.

Club Chambers for the Married.

Needle-making.

Preserved Meats.

London Stout.

Palace Lights, Club Cards, and
Bank Pens.

The Great Military Clothing
Establishment at Pimlico.

Thoughts about London Beggars.

Wenham Lake Ice.

Candle Making.

Woman’s Work.

The Turkish Bath.

The Nervous System of the
Metropolis.

Who is Mr. Reuter ?

Our Modern Mercury.

The Sewing Machine.

The Times’ Advertising Sheet.

Old Things by New Names.

A Suburban Fair.

A Fortnight in North Wales.

The Aristocratic Rooks.

The Englishman Abroad.

A Gossip about the Lakes.

Sensations of a Summer Night
and Morning.

Physical Antipathies.

The Philosophy of Babydom,

Brain Difficulties,

Human Hair.

Observer.
‘‘The papers are treated in such a manner as to form not merely an interesting,
but an instructive contribution to the stock of popular literature, and the volume is
therefore a welcome contribution to our current literature.’’

Rozert Harpwicke, 192, Piccadilly, w.

Chemistry. é

Three Parts, 2d. each; complete, 6d.; cloth, 8d. An introduction to Chemistry,
including a popular summary of animal and vegetable physiology, accompanied
by various chemical tables, with numerous illustrations. Containing :—Acids—
Albumen—Alcohol—Alkoloids—Atomic theory—Attraction, chemical—Bases—
Binary compounds—Carbon—Chemical affinity—Clays—Classification of metals—
Colouring metals—Combustion—Divisibility of matter—Elective attraction—
Electro-chemistry—Elementary bodies—Elements—Fermentation—Fixed oils—
Forms of matter—Gaseous combinations—Hydrogen— Intermediate Elements—
Life—Matter—Nitrogen—Nomenclature—Oils and fat—Organization—Oxidation
—Oxygen—Primary compounds—Products of fermentation—Proximate elements
—Salts—Simple substances—Specific gravities, tables of—Spontaneous combus-
tion—Starch—Theory of the Ethers—Vegetable acids, &c. &c.—and other very
useful information. 144 closely but clearly printed pages. Fully illustrated.

Hydraulics. Pneumatics.
Fully Ilustrated. Complete, 2d.; cloth, 4d. | Fully Illustrated. Complete, 2d.; cloth, 4d.
Optics.

Fully Illustrated. Two parts, 2d. each; complete, 4d.; cloth, 6d.

Other Works of a similar character are in preparation, and will
shortly be announced.

INTENDED FOR SCHOOLS OR SELF-INSTRUCTION.
Mackenzie’s Educational Books.

ALREADY PUBLISHED,
Mackenzie’s Tables.

Commercial, Arithmetical, Miscellaneous, and Artificers’. Calculations in
Bricklaying, Carpentery, Lathing, Masonry, Paper-hanging, Paving, Planting,
Plastering, Slating, Tiling, Well-sinking, Digging, &c, &c. Fractions and
Decimals. Forms of Receipts and Bills. Calculations on Man, Steam, Rail-
ways, Power, Light, Wind, &c. Language and Alphabets. Calendar of the
Church. Scripture Money. Principal Foreign Moneys and Measures, Geo-
graphical and Astronomical Tables, &c. &c. Complete, price 2d.
3 = .
Murray’s English Grammar.

Complete, word for word with the Shilling Editions. Price 2d,
Mavor’s Spelling. ‘

With numerous Cuts. Price 4d,, or 2 parts 2d. each.
Walkinghame’s Arithmetic.

Same as the Half-crown Edition. Price 4d., 07 2 parts 2d, each.

Short-Hand.

With Phrases and Exercises, to gain facility in the use of all the characters, by
which perfection may soon be attained. Complete, price 2d.

Phrenology
Explained and Exemplified. Complete, price 2d.

Bookkeeping

By Single Entry, with explanations of Subsidiary Books, being a useful system
for the Wholesale and Retail Shopkeeper. Complete, price 2d.

ADU

sy
-

34

% jem

SS eee nen eee ee ee ee ee Ge pee gd ant wag

gc le el alin ila Ea abl ll cae aT oe ee ee ge ee haat Me APM A OS GP Ogg EET a py Selah pat oi gl ag Sa tO pinyin gM ait ot ee
PTE ye mel, gt AY, hte lNmcting Py, NN ma hg AM oN le I , I, ga) ate, gfe nee 9 athe git i at a om ee 7 tn ee -
~ NE eel ana a Asal a eg tiny Mngt Ny tn iy sem ty, sh onal ad let cia ad tye? tad Nyt! te afin Ml gt eA gy Pes iy D nage hela tut tg MN cant: ig A et oy
, Siaipemscenpeersen eae Oe ee po EO Nes as Da lao tl tan al ctl a tp ier ala cal te nied aie Me
. pe Pe ee, sree ~ a ee te a ee a een mrtg Wyeth wom: ee we * ie
: SS OT eT neat «net mes emeak Nem seta oxy gen
- Thee eae oie 18 ta pte grind etm Tite ®f 7 uy eet om the,” ~i “es Wea.
> § wt *~ "x “— aod Kia Mi em hae as : " ‘ * = t a “
_ > me ax , Ra hw ee 7 : 2 we ° - = ed > >. ont . tu
¥ pe A PR a rn a ig tn ee Min Rly tod es “ Moe eh va “ty ’ “ye ‘te oy oe Pie Sy een ow
oper ee ~ Cs cr Toe a aw) ae “i - a “ mg wo Deine ae os met tee
a i ae ean Se i, a a ie ain acces cat eee i al mee Bal a Ml le Aa
APU I es cso EW NOE, aE TE a
Rh art PE PET Ie asl sl FET gh Piiy tig easel gt a ge eee pagel
oe gee BP REFER i et Maa gg AIC yg ag Py Ar gaging in ge aay reas nectar Seth agg: na as
NS NE OF PP TPR age eT Mag IT Me I gl i By 7 Reaaater Pf rn eo
RENN at aR Ral as Res ease yy ag Miyata: By neg) cm sing gn . * «
RE Ss ge gas 2 Pas ee RT Nor he React aes eg ais gm oy
= NT cp OO RO a RAS ag a a a egg Mag eh a ae FS, er aes Pogafak Sem een
as ed SDE et TSR el a BF Re a rae a oe Epo ine hk
2 - ee ll al hen tingid aa Bia idk dt de ae oe ne ne ata 7 FBP PE ht ce
a A Ot Rae ar te a Os ey" Set ag Ra Sai se ty LO TR as ty Tees seh Sa a ee a ee at a 4s
2 2 ee OA Rae eg Rage ee Ra Rai Ns Rea Nt is as a eM a Fg Alaa e . Ms we Pe RS eg gg Bw Se as
gE FRR RETR S CF RESO ORG OITA BE Eng eat hae : Aa nat Oe ae a ae a ee
2, 8 eur Ot aR RE a Sa ae a Re ee Se ae ag eT Sag a ge nee age a SNE atl SRE Pe cag i gg ag? ig Te te og,
BP RD PE Ser et RR Ta ag Regi I Sg a Rat tae oe age te bailar ile Soli te sa i aie cde eal ae ae Se
i ae ee ell ae om ed a ee ee SE IAIN EO OP SOLA GE hg BTN gg
SS SE Se eee Nee arte Rs es Se 5 AEE AP EE Pe gee a Ee
ene ; il Sena liad lial Al sill co alae’ le cain le al gla gilt ok a a nO
a eee. ee PPI PB EO EE ae og ofa
fo gee ; Set ee ae a ee ad
a MB gi TO ge SSP a GE EGE NP A I ee gD dt gy *
oat te eS SESE PNG OE REL PE EE iy, ge
ea PR ae Ey yee, BREE PS BOE gE GPE SP oP gE gt ee ss
2 Re ee ee Ste NCR Re Ae ee ee
eA kee, cbt oe Se sie ge ae eee ee
A estes gem ae NT ENE TS Eg EE ne eg as arm * a
be a Sn ae 2 EE OEE Ee ot SF te
BOM ante 2 Siesta in Ai iid in ghd die a ae en ca gl cae ee ee ew
BR ie ate i Re ag ete es Te TTR a saa a Ne NE St PR PE Ge a gp gh aeingE PRE SPOWP DO E L GPE EOGP gP o oe tn h
@) Petey RE OES RPE RS ES at PR gs BERS BRA SOR LOL RE BG ONE POS OMG Foe PARE Ne Pt
ye) WE Pe 2m pra: PSSST Ry Rt SF RES SS REE EE SRE sat OP EES 6 OE PT OO HE EE et pe A Eh ag
ST ea Be =e EEO EOE SF ORE FR I RONG GELS BF A BSF SESE SER PE EIT OE gE ye tin at AE my ae cae
we Ra 2 yO D+ eee ee Se is et ee ee SSP S OF Beet DB Re FS ag ag at SPIN OE PONE LEG 2 LO a B ghar ete 7 a
EE Re ge | aR Se Ra a Ref PS Re as a SESE eR SO aga PT og Gg rt ea gmt ge
ee thet ice!) Pisin bei ae Gdn ee ee ee a a ee SSSR SP PS gO REE ag OE I ee i EEE IO oe
NE Gy ON ORR STS REN AS SSE al IE EROS SERIES BEA OEE LE LEO EEE LA AO GE EE EN at a
MO Bog acer uO eat PRPS LOI PS SOG IO OP LOPE AI OPA fa gga SFL OE 8 BORIS aE PG ORE EE GE OB at OD o
A pO ET Sg em LSS ERE SIRE RE SIE BES PLR IG a POLES BRP UGE SERA PRE! SE SG RNS BN FER EE EE gh
gb 8 ere SEE PONE OR LS OBEN RL ELE BEEP EP a EOP NES EEE PORE OE NE Doo #
EI ee Ah pty Ae Mt ge Tay RS ES Re Sm PSL SBOE ES RBO IR GOBER OOS AP EGO GP Pe ae a ae ae ade ee eee
pet a Me chin tS th GLO RS RLR ERE EEL IRL B EAGT AGG PGE SME GP EF ee Pg gs BS ym 7
ve hk ae +. SESE EE ERLE DERE AGERE EERIE EDP BOGE BBE OP OEE POE OIE BR ee
wen ~ ENE ESE ES OLB GEE PAE BP LEER AE LOE GORE Ae Ve et
St oo PO RN EE RIESE EOL I RII IP REDE PRE BME EE GE PGE EOE I gg ea th yl ett
ane SS LEDS RIE LE ILLITE PA LEELA E E in BEAE AIRE ALLA AA RE ESE aA ee
Yvon 7 SN ee NA 8 Net ENOL OD NPR mt ee AS Se el es we ee ae ee eg " Pd
* 3 a . ree a * z OE ah NG ET) EG StS get ngs a i can rn re et an a ita aft
1m et a . Fg erate
eS z: Ni = >»
fo ® co wink
es a Paty gh
ale . Pf Aig, PS A ip Bi” Sage Yh Nl
Rye SE TG og Ne eae te - sagt: en a wee
1 4 HS er ter SE Ss ae: Eo cae eet ae oe aie ag Sp i tig a :
~~ —— = Sey
fer

La gaR GE

DREPADEVRERS SOUS REEVE TERRE ha ekek

Yos eee

&
a

a a
ea