CHAPTER XVI

THE STEPS IN THE DEVELOPMENT OF LAMARCK'S VIEWS ON EVOLUTION BEFORE THE

PUBLICATION OF HIS _PHILOSOPHIE ZOOLOGIQUE_

I. _From the Système des Animaux sans Vertèbres_ (1801).

The first occasion on which, so far as his published writings show,

Lamarck expressed his evolutional views was in the opening lecture[162]

of his course on the invertebrate animals delivered in the spring of

1800, and published in 1801 as a preface to his _Système des Animaux

sans Vertèbres_, this being the first sketch or prodromus of his later

great work on the invertebrate animals. In the preface of this book,

referring to the opening lecture, he says: "I have glanced at some

important and philosophic views that the nature and limits of this work

do not permit me to develop, but which I propose to take up elsewhere

with the details necessary to show on what facts they are based, and

with certain explanations which would prevent any one from

misunderstanding them." It may be inferred from this that he had for

some time previous meditated on this theme. It will now be interesting

to see what factors of evolution Lamarck employed in this first sketch

of his theory.

After stating the distinctions existing between the vertebrate and

invertebrate animals, and referring to the great diversity of animal

forms, he goes on to say that Nature began with the most simply

organized, and having formed them, "then with the aid of much time and

of favorable circumstances she formed all the others."

"It appears, as I have already said, that _time_ and _favorable

conditions_ are the two principal means which nature has employed in

giving existence to all her productions. We know that for her time

has no limit, and that consequently she has it always at her

disposal.

"As to the circumstances of which she has had need and of which she

makes use every day in order to cause her productions to vary, we

can say that they are in a manner inexhaustible.

"The essential ones arise from the influence and from all the

environing media (_milieux_), from the diversity of local causes

(_diversité des lieux_), of habits, of movements, of action, finally

of means of living, of preserving their lives, of defending

themselves, of multiplying themselves, etc. Moreover, as the result

of these different influences the faculties, developed and

strengthened by use (_usage_), became diversified by the new habits

maintained for long ages, and by slow degrees the structure, the

consistence, in a word the nature, the condition of the parts and of

the organs consequently participating in all these influences,

became preserved and were propagated by generation.[163]

"The bird which necessity (_besoin_) drives to the water to find

there the prey needed for its subsistence separates the toes of its

feet when it wishes to strike the water[164] and move on its

surface. The skin, which unites these toes at their base, contracts

in this way the habit of extending itself. Thus in time the broad

membranes which connect the toes of ducks, geese, etc., are formed

in the way indicated.

"But one accustomed to live perched on trees has necessarily the end

of the toes lengthened and shaped in another way. Its claws are

elongated, sharpened, and are curved and bent so as to seize the

branches on which it so often rests.

"Likewise we perceive that the shore bird, which does not care to

swim, but which, however, is obliged (a _besoin_) to approach the

water to obtain its prey, will be continually in danger of sinking

in the mud, but wishing to act so that its body shall not fall into

the liquid, it will contract the habit of extending and lengthening

its feet. Hence it will result in the generations of these birds

which continue to live in this manner, that the individuals will

find themselves raised as if on stilts, on long naked feet; namely,

denuded of feathers up to and often above the thighs.

"I could here pass in review all the classes, all the orders, all

the genera and species of animals which exist, and make it apparent

that the conformation of individuals and of their parts, their

organs, their faculties, etc., is entirely the result of

circumstances to which the race of each species has been subjected

by nature.

"I could prove that it is not the form either of the body or of its

parts which gives rise to habits, to the mode of life of animals,

but, on the contrary, it is the habits, the mode of life, and all

the influential circumstances which have, with time, made up the

form of the body and of the parts of animals. With the new forms new

faculties have been acquired, and gradually nature has reached the

state in which we actually see her" (pp. 12-15).

He then points out the gradation which exists from the most simple

animal up to the most composite, since from the monad, which, so to

speak, is only an animated point, up to the mammals, and from them up to

man, there is evidently a shaded gradation in the structure of all the

animals. So also among the plants there is a graduated series from the

simplest, such as _Mucor viridescens_, up to the most complicated plant.

But he hastens to say that by this regular gradation in the complication

of the organization he does not mean to infer the existence of a linear

series, with regular intervals between the species and genera:

"Such a series does not exist; but I speak of a series almost

regularly graduated in the principal groups (_masses_) such as the

great families; series most assuredly existing, both among animals

and among plants, but which, as regards genera and especially

species, form in many places lateral ramifications, whose

extremities offer truly isolated points."

This is the first time in the history of biological science that we have

stated in so scientific, broad, and modern form the essential

principles of evolution. Lamarck insists that time without limit and

favorable conditions are the two principal means or factors in the

production of plants and animals. Under the head of favorable conditions

he enumerates variations in climate, temperature, the action of the

environment, the diversity of local causes, change of habits, movement,

action, variation in means of living, of preservation of life, of means

of defence, and varying modes of reproduction. As the result of the

action of these different factors, the faculties of animals, developed

and strengthened by use, become diversified by the new habits, so that

by slow degrees the new structures and organs thus arising become

preserved and transmitted by heredity.

In this address it should be noticed that nothing is said of willing and

of internal feeling, which have been so much misunderstood and

ridiculed, or of the direct or indirect action of the environment. He

does speak of the bird as wishing to strike the water, but this,

liberally interpreted, is as much a physiological impulse as a mental

desire. No reference also is made to geographical isolation, a factor

which he afterwards briefly mentioned.

Although Lamarck does not mention the principle of selection, he refers

in the following way to competition, or at least to the checks on the

too rapid multiplication of the lower invertebrates:

"So were it not for the immense consumption as food which is made in

nature of animals which compose the lower orders of the animal

kingdom, these animals would soon overpower and perhaps destroy, by

their enormous numbers, the more highly organized and perfect

animals which compose the first classes and the first orders of this

kingdom, so great is the difference in the means and facility of

multiplying between the two.

"But nature has anticipated the dangerous effects of this vast power

of reproduction and multiplication. She has prevented it on the one

hand by considerably limiting the duration of life of these beings

so simply organized which compose the lower classes, and especially

the lowest orders of the animal kingdom. On the other hand, both by

making these animals the prey of each other, thus incessantly

reducing their numbers, and also by determining through the

diversity of climates the localities where they could exist, and by

the variety of seasons--_i.e._, by the influences of different

atmospheric conditions--the time during which they could maintain

their existence.

"By means of these wise precautions of nature everything is well

balanced and in order. Individuals multiply, propagate, and die in

different ways. No species predominates up to the point of effecting

the extinction of another, except, perhaps, in the highest classes,

where the multiplication of the individuals is slow and difficult;

and as the result of this state of things we conceive that in

general species are preserved" (p. 22).

Here we have in anticipation the doctrine of Malthus, which, as will be

remembered, so much impressed Charles Darwin, and led him in part to

work out his principle of natural selection.

The author then taking up other subjects, first asserts that among the

changes that animals and plants unceasingly bring about by their

production and _débris_, it is not the largest and most perfect animals

which have caused the most considerable changes, but rather the coral

polyps, etc.[165] He then, after dilating on the value of the study of

the invertebrate animals, proceeds to define them, and closes his

lecture by describing the seven classes into which he divides this

group.

II. _Recherches sur l'Organisation des Corps vivans, 1802 (Opening

Discourse)._

The following is an abstract with translations of the most important

passages relating to evolution:

That the portion of the animal kingdom treated in these lectures

comprises more species than all the other groups taken together is,

however, the least of those considerations which should interest my

hearers.

"It is the group containing the most curious forms, the richest in

marvels of every kind, the most astonishing, especially from the

singular facts of organization that they present, though it is that

hitherto the least considered under these grand points of view.

"How much better than learning the names and characters of all the

species is it to learn of the origin, relation, and mode of

existence of all the natural productions with which we are

surrounded.

"_First Part: Progress in structure of living beings in proportion

as circumstances favor them._

"When we give continued attention to the examination of the

organization of different living beings, to that of different

systems which this organization presents in each organic kingdom,

finally to certain changes which are seen to be undergone in certain

circumstances, we are convinced:

"1. That the nature of organic movement is not only to develop the

organization but also to multiply the organs and to fulfil the

functions, and that at the outset this organic movement continually

tends to restrict to functions special to certain parts the

functions which were at first general--_i.e._, common to all parts

of the body;

"2. That the result of _nutrition_ is not only to supply to the

developing organization what the organic movement tends to form, but

besides, also by a forced inequality between the matters which are

assimilated and those which are dissipated by losses, this function

at a certain term of the duration of life causes a progressive

deterioration of the organs, so that as a necessary consequence it

inevitably causes death;

"3. That the property of the movement of the fluids in the parts

which contain them is to break out passages, places of deposit, and

outlets; to there create canals and consequently different organs;

to cause these canals, as well as the organs, to vary on account of

the diversity both of the movements and of the nature of the fluids

which give rise to them; finally to enlarge, elongate, to gradually

divide and solidify [the walls of] these canals and these organs by

the matters which form and incessantly separate the fluids which are

there in movement, and one part of which is assimilated and added to

the organs, while the other is rejected and cast out;

"4. That the state of organization in each organism has been

gradually acquired by the progress of the influences of the movement

of fluids, and by those changes that these fluids have there

continually undergone in their nature and their condition through

the habitual succession of their losses and of their renewals;

"5. That each organization and each form acquired by this course of

things and by the circumstances which there have concurred, were

preserved and transmitted successively by generation [heredity]

until new modifications of these organizations and of these forms

have been acquired by the same means and by new circumstances;

"6. Finally, that from the uninterrupted concurrence of these causes

or from these laws of nature, together with much time and with an

almost inconceivable diversity of influential circumstances, organic

beings of all the orders have been successively formed.

"Considerations so extraordinary, relatively to the ideas that the

vulgar have generally formed on the nature and origin of living

bodies, will be naturally regarded by you as stretches of the

imagination unless I hasten to lay before you some observations and

facts which supply the most complete evidence.

"From the point of view of knowledge based on observation the

philosophic naturalist feels convinced that it is in that which is

called the lowest classes of the two organic kingdoms--_i.e._, in

those which comprise the most simply organized beings--that we can

collect facts the most luminous and observations the most decisive

on the _production_ and the reproduction of the living beings in

question; on the causes of the formation of the organs of these

wonderful beings; and on those of their developments, of their

diversity and their multiplicity, which increase with the concourse

of generations, of times, and of influential circumstances.

"Hence we may be assured that it is only among the singular beings

of these lowest classes, and especially in the lowest orders of

these classes, that it is possible to find on both sides the

primitive germs of life, and consequently the germs of the most

important faculties of animality and vegetality."

_Modification of the organization from one end to the other of the

animal chain._

"One is forced," he says, "to recognize that the totality of existing

animals constitute _a series of groups_ forming a true chain, and that

there exists from one end to the other of this chain a gradual

modification in the structure of the animals composing it, as also a

proportionate diminution in the number of faculties of these animals

from the highest to the lowest (the first germs), these being without

doubt the form with which nature began, with the aid of much time and

favorable circumstances, to form all the others."

He then begins with the mammals and descends to molluscs, annelids, and

insects, down to the polyps, "as it is better to proceed from the known

to the unknown;" but farther on (p. 38) he finally remarks:

"Ascend from the most simple to the most compound, depart from the

most imperfect animalcule and ascend along the scale up to the

animal richest in structure and faculties; constantly preserve the

order of relation in the group, then you will hold the true thread

which connects all the productions of nature; you will have a just

idea of its progress, and you will be convinced that the most simple

of its living productions have successively given existence to all

the others.

"_The series which constitutes the animal scale resides in the

distribution of the groups, and not in that of the individuals and

species._

"I have already said[166] that by this shaded graduation in the

complication of structure I do not mean to speak of the existence

of a linear and regular series of species or even genera: such a

series does not exist. But I speak of a quite regularly graduated

series in the principal groups, _i.e._, in the principal system of

organizations known, which give rise to classes and to great

families, series most assuredly existing both among animals and

plants, although in the consideration of genera, and especially in

that of species, it offers many lateral ramifications whose

extremities are truly isolated points.

"However, although there has been denied, in a very modern work, the

existence in the animal kingdom of a single series, natural and at

the same time graduated, in the composition of the organization of

beings which it comprehends, series in truth necessarily formed of

groups subordinated to each other as regards structure and not of

isolated species or genera, I ask where is the well-informed

naturalist who would now present a different order in the

arrangement of the twelve classes of the animal kingdom of which I

have just given an account?

"I have already stated what I think of this view, which has seemed

sublime to some moderns, and indorsed by _Professor Hermann_."

Each distinct group or mass of forms has, he says, its peculiar system

of essential organs, but each organ considered by itself does not follow

as regular a course in its degradations (modifications).

"Indeed, the least important organs, or those least essential to

life, are not always in relation to each other in their improvement

or their degradation; and an organ which in one species is atrophied

may be very perfect in another. These irregular variations in the

perfecting and in the degradation of non-essential organs are due to

the fact that these organs are oftener than the others submitted to

the influences of external circumstances, and give rise to a

diversity of species so considerable and so singularly ordered that

instead of being able to arrange them, like the groups, in a single

simple linear series under the form of a regular graduated scale,

these very species often form around the groups of which they are

part lateral ramifications, the extremities of which offer points

truly isolated.

"There is needed, in order to change each internal system of

organization, a combination of more influential circumstances, and

of more prolonged duration than to alter and modify the external

organs.

"I have observed, however, that, when circumstances demand, nature

passes from one system to another without making a leap, provided

they are allies. It is, indeed, by this faculty that she has come to

form them all in succession, in proceeding from the simple to the

more complex.

"It is so true that she has the power, that she passes from one

system to the other, not only in two different families which are

allied, but she also passes from one system to the other in the same

individual.

"The systems of organization which admit as organs of respiration

true lungs are nearer to systems which admit gills than those which

require tracheæ. Thus not only does nature pass from gills to lungs

in allied classes and families, as seen in fishes and reptiles, but

in the latter she passes even during the life of the same

individual, which successively possesses each system. We know that

the frog in the tadpole state respires by gills, while in the more

perfect state of frog it respires by lungs. We never see that nature

passes from a system with tracheæ to a system with lungs.

"_It is not the organs, i.e., the nature and form of the parts of

the body of an animal, which give rise to the special habits and

faculties, but, on the contrary, its habits, its mode of life, and

the circumstances in which individuals are placed, which have, with

time, brought about the form of its body, the number and condition

of its organs, finally the faculties which it possesses._

* * * * *

"Time and favorable circumstances are the two principal means which

nature employs to give existence to all her productions. We know

that time has for her no limit, and that consequently she has it

always at her disposition.

"As to the circumstances of which she has need (_besoin_) and which

she employs every day to bring about variations in all that she

continues to produce, we can say that they are in her in some degree

inexhaustible.

"The principal ones arise from the influence of climate, from that

of different temperatures, of the atmosphere, and from all

environing surroundings (_milieux_); from that of the diversity of

places and their situations; from that of the most ordinary habitual

movements, of actions the most frequent; finally from that of the

means of preservation, of the mode of life, of defence, of

reproduction, etc.

"Moreover, as the result of these different influences the faculties

increase and strengthen themselves by use, diversify themselves by

the new habits preserved through long periods, and insensibly the

conformation, the consistence--in a word, the nature and state of

the parts and also of the organs--consequently participate in all

these influences, are preserved and propagate themselves by

generation" (_Système des Animaux sans Vertèbres_, p. 12).

* * * * *

"It is easy for any one to see that the habit of exercising an organ

in every living being which has not reached the term of diminution

of its faculties not only makes this organ more perfect, but even

makes it acquire developments and dimensions which insensibly change

it, with the result that with time it renders it very different from

the same organ considered in another organism which has not, or has

but slightly, exercised it. It is also very easy to prove that the

constant lack of exercise of an organ gradually reduces it and ends

by atrophying it."

Then follow the facts regarding the mole, spalax, ant-eater, and the

lack of teeth in birds, the origin of shore birds, swimming birds and

perching birds, which are stated farther on.

"Thus the efforts in any direction, maintained for a long time or

made habitually by certain parts of a living body, to satisfy the

needs called out (_exigés_) by nature or by circumstances, develop

these parts and cause them to acquire dimensions and a form which

they never would have obtained if these efforts had not become an

habitual action of the animals which have exercised them.

Observations made on all the animals known would furnish examples of

this.

"When the will determines an animal to any kind of action, the

organs whose function it is to execute this action are then

immediately provoked by the flowing there of subtile fluids, which

become the determining cause of movements which perform the action

in question. A multitude of observations support this fact, which

now no one would doubt.

"It results from this that multiplied repetitions of these acts of

organization strengthen, extend, develop, and even create the organs

which are there needed. It is only necessary to closely observe that

which is everywhere happening in this respect to firmly convince

ourselves of this cause of developments and organic changes.

"However, each change acquired in an organ by habitual use

sufficient to have formed (_opéré_) it is preserved by generation,

if it is common to the individuals which unite in the reproduction

of their kind. Finally, this change propagates itself and is then

handed down (_se passe_) to all the individuals which succeed and

which are submitted to the same circumstances, without their having

been obliged to acquire it by the means which have really created

it.

"Besides, in the unions between the sexes the intermixtures between

individuals which have different qualities or forms are necessarily

opposed to the constant propagation of these qualities and forms. We

see that which in man, who is exposed to such different

circumstances which influence individuals, prevents the qualities of

accidental defects which they have happened to acquire from being

preserved and propagated by heredity (_génération_).

"You can now understand how, by such means and an inexhaustible

diversity of circumstances, nature, with sufficient length of time,

has been able to and should produce all these results.

"If I should choose here to pass in review all the classes, orders,

genera, and species of animals in existence I could make you see

that the structure of individuals and their organs, faculties, etc.,

is solely the result of circumstances to which each species and all

its races have been subjected by nature, and of habits that the

individuals of this species have been obliged to contract.

"The influences of localities and of temperatures are so striking

that naturalists have not hesitated to recognize the effects on the

structure, the developments, and the faculties of the living bodies

subject to them.

"We have long known that the animals inhabiting the torrid zone are

very different from those which live in the other zones. Buffon has

remarked that even in latitudes almost the same the animals of the

new continent are not the same as those of the old.

"Finally the Count Lacépède, wishing to give to this well-founded

fact the precision which he believed it susceptible, has traced

twenty-six zoölogical divisions on the dry parts of the globe, and

eighteen over the ocean; but there are many other influences than

those which depend on localities and temperatures.

"Everything tends, then, to prove my assertion--namely, that it is

not the form either of the body or of its parts which has given rise

to habits and to the mode of life of animals, but, on the contrary,

it is the habits, the mode of life, and all the other influential

circumstances which have with time produced the form of the bodies

and organs of animals. With new forms new faculties have been

acquired, and gradually nature has arrived at the state where we

actually see it.

* * * * *

"Finally as it is only at that extremity of the animal kingdom where

occur the most simply organized animals that we meet those which may

be regarded as the true germs of animality, and it is the same at

the same end of the vegetable series; is it not at this end of the

scale, both animal and vegetable, that nature has commenced and

recommenced without ceasing the first germ of her living production?

Who is there, in a word, who does not see that the process of

perfection of those of these first germs which circumstances have

favored will gradually and after the lapse of time give rise to all

the degrees of perfection and of the composition of the

organization, from which will result this multiplicity and this

diversity of living beings of all orders with which the exterior

surface of our globe is almost everywhere filled or covered?

"Indeed, if the manner (_usage_) of life tends to develop the

organization, and even to form and multiply the organs, as the state

of an animal which has just been born proves it, compared to that

where it finds itself when it has reached the term where its organs

(beginning to deteriorate) cease to make new developments; if, then,

each particular organ undergoes remarkable changes, according as it

is exercised and according to the manner of which I have shown you

some examples, you will understand that in carrying you to the end

of the animal chain where are found the most simple organizations,

and that in considering among these organizations those whose

simplicity is so great that they lie at the very door of the

creative power of nature, then this same nature--that is to say, the

state of things which exist--has been to form directly the first

beginnings of organization; she has been able, consequently, by the

manner of life and the aid of circumstances which favor its

duration, to progressively render perfect its work, and to carry it

to the point where we now see it.

"Time is wanting to present to you the series of results of my

researches on this interesting subject, and to develop--

"1. What really is life.

"2. How nature herself creates the first traces of organization in

appropriate groups where it had not existed.

"3. How the organic or vital movement is excited by it and held

together with the aid of a stimulating and active cause which she

has at her disposal in abundance in certain climates and in certain

seasons of the year.

"4. Finally, how this organic movement, by the influence of its

duration and by that of the multitude of circumstances which modify

its effects, develops, arranges, and gradually complicates the

organs of the living body which possesses them.

"Such has been without doubt the will of the infinite wisdom which

reigns throughout nature; and such is effectively the order of

things clearly indicated by the observation of all the facts which

relate to them." (End of the opening discourse.)

APPENDIX (p. 141).

_On Species in Living Bodies._

"I have for a long time thought that _species_ were constant in

nature, and that they were constituted by the individuals which

belong to each of them.

"I am now convinced that I was in error in this respect, and that in

reality only individuals exist in nature.

"The origin of this error, which I have shared with many naturalists

who still hold it, arises from _the long duration_, in relation to

us, _of the same state of things_ in each place which each organism

inhabits; but this duration of the same state of things for each

place has its limits, and with much time it makes changes in each

point of the surface of the globe, which produces changes in every

kind of circumstances for the organisms which inhabit it.

"Indeed, we may now be assured that nothing on the surface of the

terrestrial globe remains in the same state. Everything, after a

while, undergoes different changes, more or less prompt, according

to the nature of the objects and of circumstances. Elevated areas

are constantly being lowered, and the loose material carried down to

the lowlands. The beds of rivers, of streams, of even the sea, are

gradually removed and changed, as also the climate;[167] in a word,

the whole surface of the earth gradually undergoes a change in

situation, form, nature, and aspect. We see on every hand what

ascertained facts prove; it is only necessary to observe and to give

one's attention to be convinced of it.

"However, if, relatively to living beings, the diversity of

circumstances brings about for them a diversity of habits, a

different mode of existence, and, as the result, modifications in

their organs and in the shape of their parts, one should believe

that very gradually every living body whatever would vary in its

organization and its form.

"All the modifications that each living being will have undergone as

the result of change of circumstances which have influenced its

nature will doubtless be propagated by heredity (_génération_). But

as new modifications will necessarily continue to operate, however

slowly, not only will there continually be found new species, new

genera, and even new orders, but each species will vary in some part

of its structure and its form.

"I very well know that to our eyes there seems in this respect a

_stability_ which we believe to be constant, although it is not so

truly; for a very great number of centuries may form a period

insufficient for the changes of which I speak to be marked enough

for us to appreciate them. Thus we say that the flamingo

(_Phoenicopterus_) has always had as long legs and as long a neck

as have those with which we are familiar; finally, it is said that

all animals whose history has been transmitted for 2,000 or 3,000

years are always the same, and have lost or acquired nothing in the

process of perfection of their organs and in the form of their

different parts. We may be assured that this appearance of

_stability_ of things in nature will always be taken for reality by

the average of mankind, because in general it judges everything only

relatively to itself.

"But, I repeat, this consideration which has given rise to the

admitted error owes its source to the very great slowness of the

changes which have gone on. A little attention given to the facts

which I am about to cite will afford the strongest proof of my

assertion.

"What nature does after a great length of time we do every day by

suddenly changing, as regards a living being, the circumstances in

which it and all the individuals of its species are placed.

"All botanists know that the plants which they transplant from their

natal spot into gardens for cultivation there gradually undergo

changes which in the end render them unrecognizable. Many plants

naturally very hairy, there become glabrous or nearly so; a quantity

of those which were procumbent or trailing there have erect stems;

others lose their spines or their thorns; finally, the dimensions of

parts undergo changes which the circumstances of their new situation

infallibly produce. This is so well known that botanists prefer not

to describe them, at least unless they are newly cultivated. Is not

wheat (_Triticum sativum_) a plant brought by man to the state

wherein we actually see it, which otherwise I could not believe? Who

can now say in what place its like lives in nature?

"To these known facts I will add others still more remarkable, and

which confirm the view that change of circumstances operates to

change the parts of living organisms.

"When _Ranunculus aquatilis_ lives in deep water, all it can do

while growing is to make the end of its stalks reach the surface of

the water where they flourish. Then all the leaves of the plant are

finely cut or pinked.[168] If the same plant grows in shallower

water the growth of its stalks may give them sufficient extent for

the upper leaves to develop out of the water; then its lower leaves

only will be divided into hair-like joints, while the upper ones

will be simple, rounded, and a little lobed.[169] This is not all:

when the seeds of the same plant fall into some ditch where there is

only water or moisture sufficient to make them germinate, the plant

develops all its leaves in the air, and then none of them is divided

into capillary points, which gives rise to _Ranunculus hederaceus_,

which botanists regard as a species.

"Another very striking proof of the effect of a change of

circumstances on a plant submitted to it is the following:

"It is observed that when a tuft of _Juncus bufonius_ grows very

near the edge of the water in a ditch or marsh this rush then pushes

out filiform stems which lie in the water, are there deformed,

becoming disturbed (_traçantes_), proliferous, and very different

from that of _Juncus bufonius_ which grows out of water. This plant,

modified by the circumstances I have just indicated, has been

regarded as a distinct species; it is the _Juncus supinus_ of

Rotte.[170]

"I could also give citations to prove that the changes of

circumstances relative to organisms necessarily change the

influences which they undergo on the part of all that which environs

them or which acts on them, and so necessarily bring about changes

in their size, their shape, their different organs.

"Then among living beings nature seems to me to offer in an absolute

manner only individuals which succeed one another by generation.

"However, in order to facilitate the study and recognition of these

organisms, I give the name of _species_ to every collection of

individuals which during a long period resemble each other so much

in all their parts that these individuals only present small

accidental differences which, in plants, reproduction by seeds

causes to disappear.

"But, besides that at the end of a long period the totality of

individuals of such a species change as the circumstances which act

on them, those of these individuals which from special causes are

transported into very different situations from those where the

others occur, and then constantly submitted to other influences--the

former, I say, assume new forms as the result of a long habit of

this other mode of existence, and then they constitute a new

_species_, which comprehends all the individuals which occur in the

same condition of existence. We see, then, the faithful picture of

that which happened in this respect in nature, and of that which the

observation of its acts can alone discover to us."

III. _Lamarck's Views on Species, as published in 1803._

In the opening lecture[171] of his course at the Museum of Natural

History, delivered in prairial (May 20-June 18), 1803, we have a

further statement of the theoretical views of Lamarck on species and

their origin. He addresses his audience as "Citoyens," France still

being under the _régime_ of the Republic.

The brochure containing this address is exceedingly rare, the only copy

existing, as far as we know, being in the library of the Museum of

Natural History in Paris. The author's name is not even given, and there

is no imprint. Lamarck's name, however, is written on the outside of the

cover of the copy we have translated. At the end of the otherwise blank

page succeeding the last page (p. 46) is printed the words: _Esquisse

d'un Philosophie zoologique_, the preliminary sketch, however, never

having been added.

He begins by telling his hearers that they should not desire to burden

their memories with the infinite details and immense nomenclature of

the prodigious quantity of animals among which we distinguish an

illimitable number of species, "but what is more worthy of you, and of

more educational value, you should seek to know the course of nature."

"You may enter upon the study of classes, orders, genera, and even of

the most interesting species, because this would be useful to you; but

you should never forget that all these subdivisions, which could not,

however, be well spared, are artificial, and that nature does not

recognize any of them."

"In the opening lecture of my last year's course I tried to convince

you that it is only in the organization of animals that we find the

foundation of the natural relations between the different groups,

where they diverge and where they approach each other. Finally, I

tried to show you that the enormous series of animals which nature

has produced presents, from that of its extremities where are placed

the most perfect animals, down to that which comprises the most

imperfect, or the most simple, an evident modification, though

irregularly defined (_nuancé_), in the structure of the

organization.

"To-day, after having recalled some of the essential considerations

which form the base of this great truth; after having shown you the

principal means by which nature is enabled to create (_opérer_) her

innumerable productions and to vary them infinitely; finally, after

having made you see that in the use she has made of her power of

generating and multiplying living beings she has necessarily

proceeded from the more simple to the more complex, gradually

complicating the organization of these bodies, as also the

composition of their substance, while also in that which she has

done on non-living bodies she has occupied herself unremittingly in

the destruction of all preëxistent combinations, I shall undertake

to examine under your eyes the great question in natural

history--What is a _species_ among organized beings?

"When we consider the series of animals, beginning at the end

comprising the most perfect and complicated, and passing down

through all the degrees of this series to the other end, we see a

very evident modification in structure and faculties. On the

contrary, if we begin with the end which comprises animals the most

simple in organization, the poorest in faculties and in organs--in a

word, the most imperfect in all respects--we necessarily remark, as

we gradually ascend in the series, a truly progressive complication

in the organization of these different animals, and we see the

organs and faculties of these beings successively multiplying and

diversifying in a most remarkable manner.

"These facts once known present truths which are, to some extent,

eternal; for nothing here is the product of our imagination or of

our arbitrary principles; that which I have just explained rests

neither on systems nor on any hypothesis: it is only the very simple

result of the observation of nature; hence I do not fear to advance

the view that all that one can imagine, from any motives whatever,

to contradict these great verities will always be destroyed by the

evidence of the facts with which it deals.

"To these facts it is necessary to add these very important

considerations, which observation has led me to perceive, and the

basis of which will always be recognized by those who pay attention

to them; they are as follows:

"Firstly, the exercise of life, and consequently of organic

movement, constitutes its activity, tends, without ceasing, not only

to develop and to extend the organization, but it tends besides to

multiply the organs and to isolate them in special centres

(_foyers_). To make sure whether the exercise of life tends to

extend and develop the organization, it suffices to consider the

state of the organs of any animal which has just been born, and to

compare them in this condition with what they are when the animal

has attained the period when its organs cease to receive any new

development. Then we will see on what this organic law is based,

which I have published in my _Recherches sur les Corps vivans_

(p. 8), _i.e._, that--

"'The special property of movement of fluids in the supple parts of

the living body which contain them is to open (_frayer_) there

routes, places of deposit and tissues; to create there canals, and

consequently different organs; to cause these canals and these

organs to vary there by reason of the diversity both of the

movements as well as the nature of the fluids which occur there;

finally to enlarge, to elongate, to divide and to gradually

strengthen (_affermir_) these canals and their organs by the matters

which are formed in the fluids in motion, which incessantly separate

themselves, and a part of which is assimilated and united with

organs while the rest is rejected.'

"Secondly, the continual employment of an organ, especially if it is

strongly exercised, strengthens this organ, develops it, increases

its dimensions, enlarges and extends its faculties.

"This second law of effects of exercise of life has been understood

for a long time by those observers who have paid attention to the

phenomena of organization.

"Indeed, we know that all the time that an organ, or a system of

organs, is rigorously exercised throughout a long time, not only its

power, and the parts which form it, grow and strengthen themselves,

but there are proofs that this organ, or system of organs, at that

time attracts to itself the principal active forces of the life of

the individual, because it becomes the cause which, under these

conditions, makes the functions of other organs to be diminished in

power.

"Thus not only every organ or every part of the body, whether of man

or of animals, being for a long period and more vigorously exercised

than the others, has acquired a power and facility of action that

the same organ could not have had before, and that it has never had

in individuals which have exercised less, but also we consequently

remark that the excessive employment of this organ diminishes the

functions of the others and proportionately enfeebles them.

"The man who habitually and vigorously exercises the organ of his

intelligence develops and acquires a great facility of attention, of

aptitude for thought, etc., but he has a feeble stomach and strongly

limited muscular powers. He, on the contrary, who thinks little does

not easily, and then only momentarily fixes his attention, while

habitually giving much exercise to his muscular organs, has much

vigor, possesses an excellent digestion, and is not given to the

abstemiousness of the savant and man of letters.

"Moreover, when one exercises long and vigorously an organ or system

of organs, the active forces of life (in my opinion, the nervous

fluid) have taken such a habit of acting (_porter_) towards this

organ that they have formed in the individual an inclination to

continue to exercise which it is difficult for it to overcome.

"Hence it happens that the more we exercise an organ, the more we

use it with facility, the more does it result that we perceive the

need (_besoin_) of continuing to use it at the times when it is

placed in action. So we remark that the habit of study, of

application, of work, or of any other exercise of our organs or of

any one of our organs, becomes with time an indispensable need to

the individual, and often a passion which it does not know how to

overcome.

"Thirdly, finally, the effort made by necessity to obtain new

faculties is aided by the concurrence of favorable circumstances;

they create (_créent_) with time the new organs which are adapted

(_propres_) to their faculties, and which as the result develop

after long use (_qu'en suite un long emploi développe_).

"How important is this consideration, and what light it spreads on

the state of organization of the different animals now living!

"Assuredly it will not be those who have long been in the habit of

observing nature, and who have followed attentively that which

happens to living individuals (to animals and to plants), who will

deny that a great change in the circumstances of their situation and

of their means of existence forces them and their race to adopt new

habits; it will not be those, I say, who attempt to contest the

foundation of the consideration which I have just exposed.

"They can readily convince themselves of the solidity of that which

I have already published in this respect.[172]

"I have felt obliged to recall to you these great considerations, a

sketch of which I traced for you last year, and which I have stated

for the most part in my different works, because they serve, as you

have seen, as a solution of the problem which interests so many

naturalists, and which concerns the determination of _species_ among

living bodies.

"Indeed, if in ascending in the series of animals from the most

simply organized animalcule, as from the monad, which seems to be

only an animated point, up to the animals the most perfect, or whose

structure is the most complicated--in a word, up to animals with

mammæ--you observe in the different orders which comprise this great

series a gradation, shaded (_nuancé_), although irregular, in the

composition of the organization and in the increasing number of

faculties, is it not evident that in the case where nature would

exert some active power on the existence of these organized bodies

she has been able to make them exist only by beginning with the most

simple, and that she has been able to form directly among the

animals only that which I call the rough sketches or germs

(_ébauches_) of animality--that is to say, only these animalcules,

almost invisible and to some extent without consistence, that we see

develop spontaneously and in an astonishing abundance in certain

places and under certain circumstances, while only in contrary

circumstances are they totally destroyed?

"Do we not therefore perceive that by the action of the laws of

organization, which I have just now indicated, and by that of

different means of multiplication which are due to them (_qui en

dérivent_), nature has in favorable times, places, and climates

multiplied her first germs (_ébauches_) of animality, given place to

developments of their organizations, rendered gradually greater the

duration of those which have originally descended from them, and

increased and diversified their organs? Then always preserving the

progress acquired by the reproductions of individuals and the

succession of generations, and aided by much time and by a slow but

constant diversity of circumstances, she has gradually brought about

in this respect the state of things which we now observe.

"How grand is this consideration, and especially how remote is it

from all that is generally thought on this subject! Moreover, the

astonishment which its novelty and its singularity may excite in you

requires that at first you should suspend your judgment in regard to

it. But the observation which establishes it is now on record

(_consignée_), and the facts which support it exist and are

incessantly renewed; however, as they open a vast field to your

studies and to your own researches, it is to you yourselves that I

appeal to pronounce on this great subject when you have sufficiently

examined and followed all the facts which relate to it.

"If among living bodies there are any the consideration of whose

organization and of the phenomena which they produce can enlighten

us as to the power of nature and its course relatively to the

existence of these bodies, also as to the variations which they

undergo, we certainly have to seek for them in the lowest classes of

the two organic kingdoms (the animals and the plants). It is in the

classes which comprise the living bodies whose organization is the

least complex that we can observe and bring together facts the most

luminous, observations the most decisive on the origin of these

bodies, on their reproduction and their admirable diversification,

finally on the formation and the development of their different

organs, the whole process being aided by the concurrence of

generations, of time, and of circumstances.

"It is, indeed, among living bodies the most multiplied, the most

numerous in nature, the most prompt and easy to regenerate

themselves, that we should seek the most instructive facts bearing

on the course of nature and on the means she has employed to create

her innumerable productions. In this case we perceive that,

relatively to the animal kingdom, we should chiefly give our

attention to the invertebrate animals, because their enormous

multiplicity in nature, the singular diversity of their systems of

organization and of their means of multiplication, their increasing

simplification, and the extreme fugacity of those which compose the

lowest orders of these animals, show us much better than the others

the true course of nature, and the means which she has used and

which she is still incessantly employing to give existence to all

the living bodies of which we have knowledge.

"Her course and her means are without doubt the same for the

production of the different plants which exist. And, indeed, though

it is not believed, as some naturalists have wrongly held, but

without proof, that plants are bodies more simple in organization

than the most simple animals, it is a veritable error which

observation plainly denies.

"Truly, vegetable substance is less surcharged with constituent

principles than any animal substance whatever, or at least most of

them, but the substance of a living body and the organization of

these bodies are two very different things. But there is in plants,

as in animals, a true gradation in organization from the plant

simplest in organization and parts up to plants the most complex in

structure and with the most diversified organs.

"If there is some approach, or at least some comparison to make

between vegetables and animals, this can only be by opposing plants

the most simply organized, like fungi and algæ, to the most

imperfect animals like the polyps, and especially the amorphous

polyps, which occur in the lowest order.

"At present we clearly see that in order to bring about the

existence of animals of all the classes, of all the orders, and of

all the genera, nature has had to begin by giving existence to those

which are the most simple in organization and lacking most in organs

and faculties, the frailest in constituency, the most ephemeral, the

quickest and easiest to multiply; and we shall find in the

_amorphous_ or _microscopic polyps_ the most striking examples of

this simplification of organization, and the indication that it is

solely among them that occur the astonishing germs of animality.

"At present we only know the principal law of the organization, the

power of the exercise of the functions of life, the influence of the

movement of fluids in the supple parts of organic bodies, and the

power which the regenerations have of conserving the progress

acquired in the composition of organs.

"At present, finally, relying on numerous observations, seeing that

with the aid of much time, of changes in local circumstances, in

climates, and consequently in the habits of animals, the progression

in the complication of their organization and in the diversity of

their parts has gradually operated (_a dû s'opérer_) in a way that

all the animals now known have been successively formed such as we

now see them, it becomes possible to find the solution of the

following question:

"What is a _species_ among living beings?

"All those who have much to do with the study of natural history

know that naturalists at the present day are extremely embarrassed

in defining what they mean by the word species.

"In truth, observation for a long time has shown us, and shows us

still in a great number of cases, collections of individuals which

resemble each other so much in their organization and by the

_ensemble_ of their parts that we do not hesitate to regard these

collections of similar individuals as constituting so many species.

"From this consideration we call _species_ every collection of

individuals which are alike or almost so, and we remark that the

regeneration of these individuals conserves the species and

propagates it in continuing successively to reproduce similar

individuals.

"Formerly it was supposed that each species was immutable, as old as

nature, and that she had caused its special creation by the Supreme

Author of all which exists.

"But we can impose on him laws in the execution of his will, and

determine the mode which he has been pleased to follow in this

respect, so it is only in this way that he permits us to recognize

it by the aid of observation. Has not his infinite power created an

order of things which successively gives existence to all that we

see as well as to all that which exists and which we do not know?

"Assuredly, whatever has been his will, the omnipotence of his power

is always the same; and in whatever way this supreme will has been

manifested, nothing can diminish its greatness. As regards, then,

the decrees of this infinite wisdom, I confine myself to the limits

of a simple observer of nature. Then, if I discover anything in the

course that nature follows in her creations, I shall say, without

fear of deceiving myself, that it has pleased its author that she

possesses this power.

"The idea that was held as to species among living bodies was quite

simple, easy to grasp, and seemed confirmed by the constancy in the

similar form of the individuals which reproduction or generation

perpetuated. There still occur among us a very great number of these

pretended species which we see every day.

"However, the farther we advance in the knowledge of the different

organized bodies with which almost every part of the surface of the

globe is covered, the more does our embarrassment increase in

determining what should be regarded as species, and the greater is

the reason for limiting and distinguishing the genera.

"As we gradually gather the productions of nature, as our

collections gradually grow richer, we see almost all the gaps filled

up, and our lines of demarcation effaced. We find ourselves

compelled to make an arbitrary determination, which sometimes leads

us to seize upon the slightest differences between varieties to form

of them the character of that which we call species, and sometimes

one person designates as a variety of such a species individuals a

little different, which others regard as constituting a particular

species.

"I repeat, the richer our collections become, the more numerous are

the proofs that all is more or less shaded (_nuancé_), that the

remarkable differences become obliterated, and that the more often

nature leaves it at our disposal to establish distinctions only

minute, and in some degree trivial peculiarities.

"But some genera among animals and plants are of such an extent,

from the number of species they contain, that the study and the

determination of these species are now almost impossible. The

species of these genera, arranged in series and placed together

according to their natural relations, present, with those allied to

them, differences so slight that they shade into each other; and

because these species are in some degree confounded with one another

they leave almost no means of determining, by expression in words,

the small differences which distinguish them.

"There are also those who have been for a long time, and strongly,

occupied with the determination of the species, and who have

consulted rich collections, who can understand up to what point

species, among living bodies, merge one into another (_fondent les

unes dans les autres_), and who have been able to convince

themselves, in the regions (_parties_) where we see isolated

species, that this is only because there are wanting other species

which are more nearly related, and which we have not yet collected.

"I do not mean to say by this that the existing animals form a very

simple series, one everywhere equally graduated; but I say that they

form a branching series, irregularly graduated, and which has no

discontinuity in its parts, or which at best has not always had, if

it is true that it is to be found anywhere (_s'il est vrai qu'il

s'en trouve quelque part_). It results from this that the species

which terminates each branch of the general series holds a place at

least on one side apart from the other allied species which

intergrade with them. Behold this state of things, so well known,

which I am now compelled to demonstrate.

"I have no need (_besoin_) of any hypothesis or any supposition for

this: I call to witness all observing naturalists.

"Not only many genera, but entire orders, and some classes even,

already present us with portions almost complete of the state of

things which I have just indicated.

"However, when in this case we have arranged the species in series,

and they are all well placed according to their natural relations,

if you select one of them, and it results in making a leap (_saut

pardessus_) over to several others, you take another one of them a

little less remote; these two species, placed in comparison, will

then present the greatest differences from each other. It is thus

that we had begun to regard most of the productions of nature which

occur at our door. Then the generic and specific distinctions were

very easy to establish. But now that our collections are very much

richer, if you follow the series that I have cited above, from the

species that you first chose up to that which you took in the second

place, and which is very different from the first, you have passed

from shade to shade without having remarked any differences worth

noticing.

"I ask what experienced zoölogist or botanist is there who has not

thoroughly realized that which I have just explained to you?

"Or how can one study, or how can one be able to determine in a

thorough way the species, among the multitude of known polyps of all

orders of radiates, worms, and especially of insects, where the

simple genera of Papilio, Phalæna, Noctua, Tinea, Musca, Ichneumon,

Curculio, Capricorn, Scarabæus, Cetonia, etc., etc., already contain

so many closely allied species which shade into each other, are

almost confounded one with another? What a host of molluscan shells

exist in every country and in all seas which elude our means of

distinction, and exhaust our resources in this respect! Ascend to

the fishes, to the reptiles, to the birds, even to the mammals, and

you will see, except the lacunæ which are still to be filled,

everywhere shadings which take place between allied species, even

the genera, and where after the most industrious study we fail to

establish good distinctions. Does not botany, which considers the

other series, comprising the plants, offer us, in its different

parts, a state of things perfectly similar? In short, what

difficulties do not arise in the study and in the determination of

species in the genera Lichena, Fucus, Carex, Poa, Piper, Euphorbia,

Erica, Hieracium, Solanum, Geranium, Mimosa, etc., etc.?

"When these genera were established but a small number of species

were known, and then it was easy to distinguish them; but at present

almost all the gaps between them are filled, and our specific

differences are necessarily minute and very often insufficient.

"From this state of things well established we see what are the

causes which have given rise to them; we see whether nature

possesses the means for this, and if observation has been able to

give us our explanation of it.

"A great many facts teach us that gradually as the individuals of

one of our species change their situation, climate, mode of life, or

habits, they thus receive influences which gradually change the

consistence and the proportions of their parts, their form, their

faculties, even their organization; so that all of them participate

eventually in the changes which they have undergone.

"In the same climate, very different situations and exposures at

first cause simple variations in the individuals which are found

exposed there; but, as time goes on, the continual differences of

situation of individuals of which I have spoken, which live and

successively reproduce in the same circumstances, give rise among

them to differences which are, in some degree, essential to their

being, in such a way that at the end of many successive generations

these individuals, which originally belonged to another species, are

at the end transformed into a new species, distinct from the other.

"For example, if the seeds of a grass, or of every other plant

natural to a humid field, should be transplanted, by an accident, at

first to the slope of a neighboring hill, where the soil, although

more elevated, would yet be quite cool (_frais_) so as to allow the

plant to live, and then after having lived there, and passed through

many generations there, it should gradually reach the poor and

almost arid soil of a mountain side--if the plant should thrive and

live there and perpetuate itself during a series of generations, it

would then be so changed that the botanists who should find it there

would describe it as a separate species.

"The same thing happens to animals which circumstances have forced

to change their climate, manner of living, and habits; but for these

the influences of the causes which I have just cited need still more

time than in the case of plants to produce the notable changes in

the individuals, though in the long run, however, they always

succeed in bringing them about.

"The idea of defining under the word _species_ a collection of

similar individuals which perpetuate the same by generation, and

which have existed thus as anciently as nature, implies the

necessity that the individuals of one and the same species cannot

mix, in their acts of generation, with the individuals of a

different species. Unfortunately observation has proved, and still

proves every day, that this consideration has no basis; for the

hybrids, very common among plants, and the unions which are often

observed between the individuals of very different species among

animals, have made us perceive that the limits between these

species, supposed to be constant, are not so rigid as is supposed.

"In truth, nothing often results from these singular unions,

especially when they are very incongruous, as the individuals which

result from them are usually sterile; but also, when the disparities

are less great, it is known that the drawbacks (_défauts_) with

which it has to do no longer exist. However, this means alone

suffices to gradually create the varieties which have afterwards

arisen from races, and which, with time, constitute that which we

call _species_.

"To judge whether the idea which is formed of species has any real

foundation, let us return to the considerations which I have already

stated; they are, namely--

"1. That all the organic bodies of our globe are veritable

productions of nature, which she has created in succession at the

end of much time.

"2. That in her course nature has begun, and begins anew every day,

by forming the simplest organic bodies, and that she directly forms

only these--that is to say, only these first primitive germs

(_ébauches_) of organization, which have been badly characterized by

the expression of "spontaneous generations" (_qu'on a désignées

mal-à-propos par l'expression de Générations spontanées_).

"3. That the first germs (_ébauches_) of the animals and plants were

formed in favorable places and circumstances. The functions of life

beginning and an organic movement established, these have

necessarily gradually developed the organs, so that after a time and

under suitable circumstances they have been differentiated, as also

the different parts (_elles les ont diversifiés ainsi qui les

parties_).

"4. That the power of increase in each portion of organic bodies

being inherited at the first production (_effets_) of life, it has

given rise to different modes of multiplication and of regeneration

of individuals; and in that way the progress acquired in the

composition of the organization and in the forms and the diversity

of the parts has been preserved.

"5. That with the aid of sufficient time, of circumstances which

have been necessarily favorable, of changes that all parts of the

surface of the globe have successively undergone in their

condition--in a word, with the power that new situations and new

habits have in modifying the organs of bodies endowed with life--all

those which now exist have been imperceptibly formed such as we see

them.

"6. Finally, that according to a similar order of things, living

beings, having undergone each of the more or less great changes in

the condition of their organization and of their parts, that which

is designated as a species among them has been insensibly and

successively so formed, can have only a relative constancy in its

condition, and cannot be as ancient as nature.

"But, it will be said, when it is necessary to suppose that, with

the aid of much time and of an infinite variation in circumstances,

nature has gradually formed the different animals that we know,

would we not be stopped in this supposition by the sole

consideration of the admirable diversity which we observe in the

instinct of different animals, and by that of the marvels of all

sorts which their different kinds of industry present?

"Will one dare to carry the spirit of system (_porter l'esprit de

système_) to the point of saying that it is nature, and she alone,

which creates this astonishing diversity of means, of ruses, of

skill, of precautions, of patience, of which the industry of animals

offers us so many examples! What we observe in this respect in the

class of insects alone, is it not a thousand times more than is

necessary to compel us to perceive that the limits of the power of

nature by no means permit her herself to produce so many marvels,

and to force the most obstinate philosophy to recognize that here

the will of the supreme author of all things has been necessary, and

has alone sufficed to cause the existence of so many admirable

things?

"Without doubt one would be rash, or rather wholly unreasonable, to

pretend to assign limits to the power of the first author of all

things; and by that alone no one can dare to say that this infinite

power has not been able to will that which nature herself shows us

she has willed.

"This being so, if I discover that nature herself brings about or

causes all the wonders just cited; that she creates the

organization, the life, even feeling; that she multiplies and

diversifies, within limits which are not known to us, the organs and

faculties of organic bodies the existence of which she sustains or

propagates; that she has created in animals by the single way of

_need_, which establishes and directs the habits, the source of all

actions, from the most simple up to those which constitute

_instinct_, industry, finally reason, should I not recognize in this

power of nature--that is to say, of existing things--the execution

of the will of its sublime author, who has been able to will that it

should have this power? Shall I any the less wonder at the

omnipotence of the power of the first cause of all things, if it has

pleased itself that things should be thus, than if by so many

(separate) acts of his omnipotent will he should be occupied and

occupy himself still continually with details of all the special

creations, all the variations, and all the developments and

perfections, all the destructions and all the renewals--in a word,

with all the changes which are in general produced in things which

exist?

"But I intend to prove in my 'Biologie' that nature possesses in her

_faculties_ all that is necessary to have to be able herself to

produce that which we admire in her works; and regarding this

subject I shall then enter into sufficient details which I am here

obliged to omit.[173]

"However, it is still objected that all we see stated regarding the

state of living bodies are unalterable conditions in the

preservation of their form, and it is thought that all the animals

whom history has transmitted to us for two or three thousand years

have always remained the same, and have lost nothing nor acquired

anything in the perfecting of their organs and in the form of their

parts.

"While this apparent stability has for a long time been accepted as

true, it has just been attempted to establish special proofs in a

report on the collections of natural history brought from Egypt by

the citizen Geoffroy."

Quotes three paragraphs in which the reporters (Cuvier and Geoffroy

St. Hilaire) say that the mummied animals of Thebes and Memphis are

perfectly similar to those of to-day. Then he goes on to say:

"I have seen them, these animals, and I believe in the conformity of

their resemblance with the individuals of the same species which

live to-day. Thus the animals which the Egyptians worshipped and

embalmed two or three thousand years ago are still in every respect

similar to those which actually live in that country.

"But it would be assuredly very singular that this should be

otherwise; for the position of Egypt and its climate are still or

very nearly the same as at former times. Therefore the animals which

live there have not been compelled to change their habits.

"There is, then, nothing in the observation which has just been

reported which should be contrary to the considerations which I

have expressed on this subject; and which especially proves that the

animals of which it treats have existed during the whole period of

nature. It only proves that they have existed for two or three

thousand years; and every one who is accustomed to reflect, and at

the same time to observe that which nature shows us of the monuments

of its antiquity, readily appreciates the value of a duration of two

or three thousand years in comparison with it.

"Hence, as I have elsewhere said, it is sure that this appearance of

the stability of things in nature will always be mistaken by the

average of mankind for the reality; because in general people only

judge of everything relatively to themselves.

"For the man who observes, and who in this respect only judges from

the changes which he himself perceives, the intervals of these

changes are _stationary conditions_ (_états_) which should appear to

be limitless, because of the brevity of life of the individuals of

his species. Thus, as the records of his observations and the notes

of facts which he has consigned to his registers only extend and

mount up to several thousands of years (three to five thousand

years), which is an infinitely small period of time relatively to

those which have sufficed to bring about the great changes which the

surface of the globe has undergone, everything seems _stable_ to him

in the planet which he inhabits, and he is inclined to reject the

monuments heaped up around him or buried in the earth which he

treads under his feet, and which surrounds him on all sides.[174]

* * * * *

"It seems to me [as mistaken as] to expect some small creatures

which only live a year, which inhabit some corner of a building,

and which we may suppose are occupied with consulting among

themselves as to the tradition, to pronounce on the duration of the

edifice where they occur: and that going back in their paltry

history to the twenty-fifth generation, they should unanimously

decide that the building which serves to shelter them is eternal, or

at least that it has always existed; because it has always appeared

the same to them; and since they have never heard it said that it

had a beginning. Great things (_grandeurs_) in extent and in

duration are relative.[175]

"When man wishes to clearly represent this truth he will be reserved

in his decisions in regard to stability, which he attributes in

nature to the state of things which he observes there.[176]

"To admit the insensible change of species, and the modifications

which individuals undergo as they are gradually forced to vary their

habits or to contract new ones, we are not reduced to the unique

consideration of too small spaces of time which our observations can

embrace to permit us to perceive these changes; for, besides this

induction, a quantity of facts collected for many years throws

sufficient light on the question that I examine, so that does not

remain undecided; and I can say now that our sciences of observation

are too advanced not to have the solution sought for made evident.

"Indeed, besides what we know of the influences and the results of

heteroclite fecundations, we know positively to-day that a forced

and long-sustained change, both in the habits and mode of life of

animals, and in the situation, soil, and climate of plants, brings

about, after a sufficient time has elapsed, a very remarkable change

in the individuals which are exposed to them.

"The animal which lives a free, wandering life on plains, where it

habitually exercises itself in running swiftly; the birds whose

needs (_besoins_) require them unceasingly to traverse great spaces

in the air, finding themselves enclosed, some in the compartments of

our menageries or in our stables, and others in our cages or in our

poultry yards, are submitted there in time to striking influences,

especially after a series of regenerations under the conditions

which have made them contract new habits. The first loses in large

part its nimbleness, its agility; its body becomes stouter, its

limbs diminish in power and suppleness, and its faculties are no

longer the same. The second become clumsy; they are unable to fly,

and grow more fleshy in all parts of their bodies.

"Behold in our stout and clumsy horses, habituated to draw heavy

loads, and which constitute a special race by always being kept

together--behold, I say, the difference in their form compared with

those of English horses, which are all slender, with long necks,

because for a long period they have been trained to run swiftly:

behold in them the influence of a difference of habit, and judge for

yourselves. You find them, then, such as they are in some degree in

nature. You find there our cock and our hen in the condition we have

[made] them, as also the mixed races that we have formed by mixed

breeding between the varieties produced in different countries, or

where they were so in the state of domesticity. You find there

likewise our different races of domestic pigeons, our different

dogs, etc. What are our cultivated fruits, our wheat, our cabbage,

our lettuce, etc., etc., if they are not the result of changes which

we ourselves have effected in these plants, in changing by our

culture the conditions of their situation? Are they now found in

this condition in nature? To these incontestable facts add the

considerations which I have discussed in my _Recherches sur les

Corps vivans_ (p. 56 _et suiv._), and decide for yourselves.

"Thus, among living bodies, nature, as I have already said, offers

only in an absolute way individuals which succeed each other

genetically, and which descend one from the other. So the _species_

among them are only relative, and only temporary.

"Nevertheless, to facilitate the study and the knowledge of so many

different bodies it is useful to give the name of _species_ to the

entire collection of individuals which are alike, which reproduction

perpetuates in the same condition as long as the conditions of their

situation do not change enough to make their habits, their

character, and their form vary.

"Such is, citizens, the exact sketch of that which goes on in nature

since she has existed, and of that which the observation of her acts

has alone enabled us to discover. I have fulfilled my object if, in

presenting to you the results of my researches and of my experience,

I have been able to disclose to you that which in your studies of

this kind deserves your special attention.

"You now doubtless conceive how important are the considerations

which I have just exposed to you, and how wrong you would be if, in

devoting yourself to the study of animals or of plants, you should

seek to see among them only the multiplied distinctions that we have

been obliged to establish; in a word, if you should confine

yourselves to fixing in your memory the variable and indefinite

nomenclature which is applied to so many different bodies, instead

of studying Nature herself--her course, her means, and the constant

results that she knows how to attain."

On the next fly page are the following words: _Esquisse d'une

Philosophie zoologique_.

IV. _Lamarck's Views as published in 1806._[177]

"Those who have observed much and have consulted the great

collections, have been able to convince themselves that as gradually

as the circumstances of their habitat, of exposure to their

surroundings, of climate, food, mode of living, etc., have changed,

the characters of size, form, of proportion between the parts, of

color, of consistence, of duration, of agility, and of industry have

proportionately changed.

"They have been able to see, as regards the animals, that the more

frequent and longer sustained use of any organ gradually strengthens

this organ, develops it, enlarges it, and gives it a power

proportional to the length of time it has been used; while the

constant lack of use of such an organ insensibly weakens it, causes

it to deteriorate, progressively diminishes its faculties, and tends

to make it waste away.[178]

"Finally, it has been remarked that all that nature has made

individuals to acquire or lose by the sustained influence of

circumstances where their race has existed for a long time, she has

preserved by heredity in the new individuals which have originated

from them (_elle le conserve par la génération aux nouveaux

individus qui en proviennent_). These verities are firmly grounded,

and can only be misunderstood by those who have never observed and

followed nature in her operations.

"Thus we are assured that that which is taken for _species_ among

living bodies, and that all the specific differences which

distinguish these natural productions, have no absolute _stability_,

but that they enjoy only a relative _stability_; which it is very

important to consider in order to fix the limits which we must

establish in the determination of that which we must call _species_.

"It is known that different places change in nature and character by

reason of their position, their 'composition' [we should say

geological structure or features], and their climate; that which is

easily perceived in passing over different places distinguished by

special characteristics; behold already a cause of variation for the

natural productions which inhabit these different places. But that

which is not sufficiently known, and even that which people refuse to

believe, is that each place itself changes after a time, in exposure,

in climate, in nature, and in character, although with a slowness so

great in relation to our period of time that we attribute to it a

perfect _stability_.

"Now, in either case, these changed places proportionately change

the circumstances relative to the living bodies which inhabit them,

and these produce again other influences on those same bodies.

"We see from this that if there are extremes in these changes there

are also gradations (_nuances_), that is to say, steps which are

intermediate, and which fill up the interval; consequently there are

also gradations in the differences which distinguish that which we

call _species_.

"Indeed, as we constantly meet with such shades (or intermediate

steps) between these so-called _species_, we find ourselves forced

to descend to the minutest details to find any distinctions; the

slightest peculiarities of form, of color, of size, and often even

of differences only perceived in the aspect of the individual

compared with other individuals which are related to it the more by

their relations, are seized upon by naturalists to establish

specific differences; so that, the slightest varieties being

reckoned as species, our catalogues of species grow infinitely

great, and the name of the productions of nature of the most

interest to us are, so to speak, buried in these enormous lists,

become very difficult to find, because now the objects are mostly

only determined by characters which our senses can scarcely enable

us to perceive.

"Meanwhile we should remember that nothing of all this exists in

nature; that she knows neither classes, orders, genera, nor species,

in spite of all the foundation which the portion of the natural

series which our collection contains has seemed to afford them; and

that of organic or living bodies there are, in reality, only

individuals, and among different races which gradually pass

(_nuancent_) into all degrees of organization" (p. 14).

On p. 70 he speaks of the animal chain from monad to man, ascending from

the most simple to the most complex. The monad is the most simple, the

most like a germ of living bodies, and from its nature passes to the

volvoces, proteus, vibrios; from them nature arrives at the production

of "polypes rotifères"--and then at "Radiaires," worms, Arachnida,

Crustacea, and Cirrhipedes.

FOOTNOTES:

[162] _Discours d'ouverture du Cours de Zoologie donné dans le Muséum

national d'Histoire naturelle, le 21 floréal, an 8 de la République_

(1800). Floréal is the name adopted by the National Convention for the

eighth month of the year. In the years of the Republic 1 to 7 it

extended from April 20 to May 19 inclusive, and in the years 8 to 13

from April 21 to May 20 (_Century Cyclopedia of Names_). The lecture,

then, in which Lamarck first presented his views was delivered on some

day between April 21 and May 20, 1800.

[163] Lamarck by the word _génération_ implies heredity. He nowhere uses

the word _hérédité_.

[164] "L'oiseau que le besoin attire sur l'eau pour y trouver la proie

qui le fait vivre, écarte les doigts de ses pieds lorsqu'il veut frapper

l'eau et se mouvoir à sa surface" (p. 13). If the word _veut_ has

suggested the doctrine of appetency in meaning has been pushed too far

by the critics of Lamarck.

[165] This he already touched upon in his _Mémoires de Physique et

d'Histoire naturelle_ (p. 342).

[166] _Système des Animaux sans Vertèbres_, pp. 16 and 17.

[167] I have cited the incontestable proofs in my _Hydrogéologie_, and I

have the conviction that one day all will be compelled to accept these

great truths.

[168] _Ranunculus aquaticus capillaceus_ (Tournef., p. 291).

[169] _Ranunculus aquaticus_ (folio rotundo et capillaceo, Tournef.,

p. 291).

[170] _Gramen junceum_, etc. (Moris, hist. 3, sec. 8, t. 9, f. 4).

[171] _Discours d'ouverture d'un Cours de Zoologie, prononcé en

prairial, an XI, au Muséum d'Histoire naturelle, sur la question,

Qu'est-ce que l'espèce parmi les corps vivans?_ (1803).

[172] _Recherches sur l'Organisation des Corps vivans_, p. 9.

[173] "See at the end of this discourse the sketch of a _Philosophie

zoologique_ relative to this subject." [This sketch was not added--only

the title at the end of the book.]

[174] See the _Annales du Muséum d'Hist. nat._, IV^e cahier. 1., 1802,

pp. 302, 303: _Mémoires sur les Fossiles des Environs de Paris_, etc. He

repeats in his _Discours_ what he wrote in 1802 in the _Annales_.

[175] _Ibid._ This is repeated from the article in the _Annales_.

[176] _Ibid._ "See my _Recherches sur les Corps vivans_" (Appendix,

p. 141).

[177] _Discours d'Ouverture du Cours des Animaux sans Vertèbres,

prononcé dans le Muséum d'Histoire naturelle en mai 1806._ (No imprint.

8^o, pp. 108.) Only the most important passages are here translated.

[178] "We know that all the forms of organs compared to the uses of

these same organs are always perfectly adapted. But there is a common

error in this connection, since it is thought that the forms of organs

have caused their functions (_en ont amené l'emploi_), whereas it is

easy to demonstrate by observation that it is the uses (_usages_) which

have given origin to the forms of organs."