Lamarck, the Founder of Evolution
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Alpheus Spring Packard >> Lamarck, the Founder of Evolution
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"This series of animals beginning with two branches where are
situated the most imperfect, the first of these branches received
their existence only by direct or spontaneous generation.
"A strong reason prevents our knowing the changes successively
brought about which have produced the condition in which we observe
them; it is because we are never witnesses of these changes. Thus we
see the work when done, but never watching them during the process,
we are naturally led to believe that things have always been as we
see them, and not as they have progressively been brought about.
"Among the changes which nature everywhere incessantly produces in
her _ensemble_, and her laws remain always the same, such of these
changes as, to bring about, do not need much more time than the
duration of human life, are easily understood by the man who
observes them; but he cannot perceive those which are accomplished
at the end of a considerable time.
"If the duration of human life only extended to the length of a
_second_, and if there existed one of our actual clocks mounted and
in movement, each individual of our species who should look at the
hour-hand of this clock would never see it change its place in the
course of his life, although this hand would really not be
stationary. The observations of thirty generations would never learn
anything very evident as to the displacement of this hand, because
its movement, only being that made during half a minute, would be
too slight to make an impression; and if observations much more
ancient should show that this same hand had really moved, those who
should see the statement would not believe it, and would suppose
there was some error, each one having always seen the hand on the
same point of the dial-plate.
"I leave to my readers all the applications to be made regarding
this supposition.
"_Nature_, that immense totality of different beings and bodies, in
every part of which exists an eternal circle of movements and
changes regulated by law; totality alone unchangeable, so long as it
pleases its SUBLIME AUTHOR to make it exist, should be regarded as a
whole constituted by its parts, for a purpose which its Author alone
knows, and not exclusively for any one of them.
"Each part necessarily is obliged to change, and to cease to be one
in order to constitute another, with interests opposed to those of
all; and if it has the power of reasoning it finds this whole
imperfect. In reality, however, this whole is perfect, and
completely fulfils the end for which it was designed."
The last work in which Lamarck discussed the theory of descent was in
his introduction to the _Animaux sans Vertebres_. But here the only
changes of importance are his four laws, which we translate, and a
somewhat different phylogeny of the animal kingdom.
The four laws differ from the two given in the _Philosophie zoologique_
in his theory (the second law) accounting for the origin of a new organ,
the result of a new need.
"_First law_: Life, by its proper forces, continually tends to
increase the volume of every body which possesses it, and to
increase the size of its parts, up to a limit which it brings about.
"_Second law_: The production of a new organ in an animal body
results from the supervention of a new want (_besoin_) which
continues to make itself felt, and of a new movement which this want
gives rise to and maintains.
"_Third law_: The development of organs and their power of action
are constantly in ratio to the employment of these organs.
"_Fourth law_: Everything which has been acquired, impressed upon,
or changed in the organization of individuals, during the course of
their life is preserved by generation and transmitted to the new
individuals which have descended from those which have undergone
those changes."
In explaining the second law he says:
"The foundation of this law derives its proof from the third, in
which the facts known allow of no doubt; for, if the forces of
action of an organ, by their increase, further develop this
organ--namely, increase its size and power, as is constantly proved
by facts--we may be assured that the forces by which it acts, just
originated by a new want felt, would necessarily give birth to the
organ adapted to satisfy this new want, if this organ had not before
existed.
"In truth, in animals so low as not to be able to _feel_, it cannot
be that we should attribute to a felt want the formation of a new
organ, this formation being in such a case the product of a
mechanical cause, as that of a new movement produced in a part of
the fluids of the animal.
"It is not the same in animals with a more complicated structure,
and which are able to _feel_. They feel wants, and each want felt,
exciting their inner feeling, forthwith sets the fluids in motion
and forces them towards the point of the body where an action may
satisfy the want experienced. Now, if there exists at this point an
organ suitable for this action, it is immediately cited to act; and
if the organ does not exist, and only the felt want be for instance
pressing and continuous, gradually the organ originates, and is
developed on account of the continuity and energy of its employment.
"If I had not been convinced: 1, that the thought alone of an action
which strongly interests it suffices to arouse the _inner feeling_
of an individual; 2, that a felt want can itself arouse the feeling
in question; 3, that every emotion of _inner feeling_, resulting
from a want which is aroused, directs at the same instant a mass of
nervous fluid to the points to be set in activity, that it also
creates a flow thither of the fluids of the body, and especially
nutrient ones; that, finally, it then places in activity the organs
already existing, or makes efforts for the formation of those which
would not have existed there, and which a continual want would
therefore render necessary--I should have had doubts as to the
reality of the law which I have just indicated.
"But, although it may be very difficult to verify this law by
observation, I have no doubt as to the grounds on which I base it,
the necessity of its existence being involved in that of the third
law, which is now well established.
"I conceive, for example, that a _gasteropod mollusc_, which, as it
crawls along, finds the need of feeling the bodies in front of it,
makes efforts to touch those bodies with some of the foremost parts
of its head, and sends to these every time supplies of nervous
fluids, as well as other fluids--I conceive, I say, that it must
result from this reiterated afflux towards the points in question
that the nerves which abut at these points will, by slow degrees, be
extended. Now, as in the same circumstances other fluids of the
animal flow also to the same places, and especially nourishing
fluids, it must follow that two or more tentacles will appear and
develop insensibly under those circumstances on the points referred
to.
"This is doubtless what has happened to all the races of
_Gasteropods_, whose wants have compelled them to adopt the habit of
feeling bodies with some part of their head.
"But if there occur, among the _Gasteropods_, any races which, by
the circumstances which concern their mode of existence or life, do
not experience such wants, then their head remains without
tentacles; it has even no projection, no traces of tentacles, and
this is what has happened in the case of _Bullaea_, _Bulla_, and
_Chiton_."
In the _Supplement a la Distribution generale des Animaux_
(Introduction, p. 342), concerning the real order of origin of the
invertebrate classes, Lamarck proposes a new genealogical tree. He
states that the order of the animal series "is far from simple, that it
is branching, and seems even to be composed of several distinct series;"
though farther on (p. 456) he adds:
"Je regarde _l'ordre de la production_ des animaux comme forme de
deux series distinctes.
"Ainsi, je soumets a la meditation des zoologistes l'ordre presume
de la _formation_ des animaux, tel que l'exprime le tableau
suivant:"
In the matter of the origin of instinct, as in evolution in general,
Lamarck appears to have laid the foundation on which Darwin's views,
though he throws aside Lamarck's factors, must rest. The "inherited
habit" theory is thus stated by Lamarck.
Instinct, he claims, is not common to all animals, since the lowest
forms, like plants, are entirely passive under the influences of the
surrounding medium; they have no wants, are automata.
"But animals with a nervous system have _wants_, _i.e._, they feel
hunger, sexual desires, they desire to avoid pain or to seek
pleasure, etc. To satisfy these wants they contract habits, which
are gradually transformed into so many propensities which they can
neither resist nor change. Hence arise habitual actions and special
_propensities_, to which we give the name of _instinct_.
"These propensities are inherited and become innate in the young, so
that they act instinctively from the moment of birth. Thus the same
habits and instincts are perpetuated from one generation to another,
with no _notable_ variations, so long as the species does not
suffer change in the circumstances essential to its mode of life."
The same views are repeated in the introduction to the _Animaux sans
Vertebres_ (1815), and again in 1820, in his last work, and do not need
to be translated, as they are repetitions of his previously published
views in the _Philosophie zoologique_.
Unfortunately, to illustrate his thoughts on instinct Lamarck does not
give us any examples, nor did he apparently observe to any great extent
the habits of animals. In these days one cannot follow him in drawing a
line--as regards the possession of instincts--between the lowest
organisms, or Protozoa, and the groups provided with a nervous system.
_Lamarck's meaning of the word "besoins," or wants or needs._--Lamarck's
use of the word wants or needs (_besoins_) has, we think, been greatly
misunderstood and at times caricatured or pronounced as "absurd." The
distinguished French naturalist, Quatrefages, although he was not
himself an evolutionist, has protested against the way Lamarck's views
have been caricatured. By nearly all authors he is represented as
claiming that by simply "willing" or "desiring" the individual bird or
other animal radically and with more or less rapidity changed its shape
or that of some particular organ or part of the body. This is, as we
have seen, by no means what he states. In no instance does he speak of
an animal as simply "desiring" to modify an organ in any way. The
doctrine of appetency attributed to Lamarck is without foundation. In
all the examples given he intimates that owing to changes in
environment, leading to isolation in a new area separating a large
number of individuals from their accustomed habitat, they are driven by
necessity (_besoin_) or new needs to adopt a new or different mode of
life--new habits. These efforts, whatever they may be--such as attempts
to fly, swim, wade, climb, burrow, etc., continued for a long time "in
all the individuals of its species," or the great number forced by
competition to migrate and become segregated from the others of the
original species--finally, owing to the changed surroundings, affect the
mass of individuals thus isolated, and their organs thus exercised in a
special direction undergo a slow modification.
Even so careful a writer as Dr. Alfred R. Wallace does not quite fairly,
or with exactness, state what Lamarck says, when in his classical essay
of 1858 he represents Lamarck as stating that the giraffe acquired its
long neck by _desiring_ to reach the foliage of the more lofty shrubs,
and constantly stretching its neck for the purpose. On the contrary, he
does not use the word "desiring" at all. What Lamarck does say is that--
"The giraffe lives in dry, desert places, without herbage, so that
it is obliged to browse on the leaves of trees, and is continually
forced to reach up to them. It results from this habit, continued
for a long time in all the individuals of its species, that its fore
limbs have become so elongated that the giraffe, without raising
itself erect on its hind legs, raises its head and reaches six
meters high (almost twenty feet)."[192]
We submit that this mode of evolution of the giraffe is quite as
reasonable as the very hypothetical one advanced by Mr. Wallace;[193]
_i.e._, that a variety occurred with a longer neck than usual, and these
"at once secured a fresh range of pasture over the same ground as their
shorter-necked companions, and on the first scarcity of food were
thereby enabled to outlive them." Mr. Wallace's account also of
Lamarck's general theory appears to us to be one-sided, inadequate, and
misleading. He states it thus: "The hypothesis of Lamarck--that
progressive changes in species have been produced by the attempts of
animals to increase the development of their own organs, and thus modify
their structure and habits." This is a caricature of what Lamarck really
taught. Wants, needs (_besoins_), volitions, desires, are not mentioned
by Lamarck in his two fundamental laws (see p. 303), and when the word
_besoins_ is introduced it refers as much to the physiological needs as
to the emotions of the animal resulting from some new environment which
forces it to adopt new habits such as means of locomotion or of
acquiring food.
It will be evident to one who has read the original or the foregoing
translations of Lamarck's writings that he does not refer so much to
mental desires or volitions as to those physiological wants or needs
thrust upon the animal by change of circumstances or by competition; and
his _besoins_ may include lust, hunger, as well as the necessity of
making muscular exertions such as walking, running, leaping, climbing,
swimming, or flying.
As we understand Lamarck, when he speaks of the incipient giraffe or
long-necked bird as making efforts to reach up or outwards, the efforts
may have been as much physiological, reflex, or instinctive as mental. A
recent writer, Dr. R. T. Jackson, curiously and yet naturally enough
uses the same phraseology as Lamarck when he says that the long siphon
of the common clam (Mya) "was brought about by the effort to reach the
surface, induced by the habit of deep burial" in its hole.[194]
On the other hand, can we in the higher vertebrates entirely dissociate
the emotional and mental activities from their physiological or
instinctive acts? Mr. Darwin, in his _Expressions of the Emotions in Man
and Animals_, discusses in an interesting and detailed way the effects
of the feelings and passions on some of the higher animals.
It is curious, also, that Dr. Erasmus Darwin went at least as far as
Lamarck in claiming that the transformations of animals "are in part
produced by their own exertions in consequence of their desires and
aversions, of their pleasures and their pains, or of irritations or of
associations."
Cope, in the final chapter of his _Primary Factors of Organic
Evolution_, entitled "The Functions of Consciousness," goes to much
farther extremes than the French philosopher has been accused of doing,
and unhesitatingly attributes consciousness to all animals. "Whatever be
its nature," he says, "the preliminary to any animal movement which is
not automatic is an effort." Hence he regards effort as the immediate
source of all movement, and considers that the control of muscular
movements by consciousness is distinctly observable; in fact, he even
goes to the length of affirming that reflex acts are the product of
conscious acts, whereas it is plain enough that reflex acts are always
the result of some stimulus.
Another case mentioned by Lamarck in his _Animaux sans Vertebres_, which
has been pronounced as absurd and ridiculous, and has aided in throwing
his whole theory into disfavor, is his way of accounting for the
development of the tentacles of the snail, which is quoted on p. 348.
This account is a very probable and, in fact, the only rational
explanation. The initial cause of such structures is the intermittent
stimulus of occasional contact with surrounding objects, the irritation
thus set up causing a flow of the blood to the exposed parts receiving
the stimuli. The general cause is the same as that concerned in the
production of horns and other hard defensive projections on the heads of
various animals.
In commenting on this case of the snail, Professor Cleland, in his just
and discriminating article on Lamarck, says:
"However absurd this may seem, it must be admitted that, unlimited
time having been once granted for organs to be developed in series
of generations, the objections to their being formed in the way here
imagined are only such as equally apply to the theory of their
origin by natural selection.... In judging the reasonableness of the
second law of Lamarck [referring to new wants, see p. 346] as
compared with more modern and now widely received theories, it must
be observed that it is only an extension of his third law; and that
third law is a fact. The strengthening of the blacksmith's arm by
use is proverbially notorious. It is, therefore, only the
sufficiency of the Lamarckian hypothesis to explain the first
commencement of new organs which is in question, if evolution by the
mere operation of forces acting in the organic world be granted; and
surely the Darwinian theory is equally helpless to account for the
beginning of a new organ, while it demands as imperatively that
every stage in the assumed hereditary development of an organ must
have been useful.... Lamarck gave great importance to the influence
of new wants acting indirectly by stimulating growth and use. Darwin
has given like importance to the effects of accidental variations
acting indirectly by giving advantage in the struggle for existence.
The speculative writings of Darwin have, however, been interwoven
with a vast number of beautiful experiments and observations bearing
on his speculations, though by no means proving his theory of
evolution; while the speculations of Lamarck lie apart from his
wonderful descriptive labors, unrelieved by intermixture with other
matters capable of attracting the numerous class who, provided they
have new facts set before them, are not careful to limit themselves
to the conclusions strictly deducible therefrom. But those who read
the _Philosophie Zoologique_ will find how many truths often
supposed to be far more modern are stated with abundant clearness in
its pages." (_Encyc. Brit._, art. "Lamarck.")
COMPARATIVE SUMMARY OF THE VIEWS OF THE FOUNDERS OF THE THEORY OF
EVOLUTION, WITH DATES OF PUBLICATION.
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|Erasmus | |Geoffroy St.|Charles
Buffon |Darwin |Lamarck |Hilaire |Darwin
(1761-1778). |(1790-1794). |(1801-1809-1815). |(1795-1831).|(1859).
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| | | |
All animals |All animals |All organisms arose from|Unity of |Universal
possibly |derived from |germs. First germ |organization|tendency to
derived from |a single |originated by |in animal |fortuitous
a single |filament. |spontaneous generation. |kingdom. |variability
type. | |Development from the | |assumed.
| |simple to the complex. |Change of |
Time, its | |Animal series not |"milieu |
great length,| |continuous, but |ambiant," |
stated. | |tree-like; graduated |direct. |
| |from monad to man; | |
Immutability | |constructed the first | |
of species | |phylogenetic tree. | |
stated and | | |Founded the |Struggle
then denied. |Time, great |Time, great length of, |doctrine of |for
|length of, |definitely postulated; |homologies. |existence.
Nature |definitely |its duration practically| |
advances by |demanded. |unlimited. | |
gradations, | | | |
passing from | |Uniformitarianism of | |
one species | |Hutton and of Lyell |Founder of |
to another by| |anticipated. |teratology. |
imperceptible| | | |
degrees. |Effects of |Effects of favorable |His embryo- |
|change of |circumstances, such as |logical |
Changes in |climate, |changes of environment, |studies |
distribution |direct |climate, soil, food, |influenced |
of land and |(briefly |temperature; direct in |his |
water as |stated). |case of plants and |philosophic |
causing | |lowest animals, indirect|views. |
variation. | |in case of the higher | |
| |animals and man. | |
Effects of | | | |
changes of | |Conditions of existence | |
climate, | |remaining constant, | |
direct. | |species do not vary and | |Competition
| |vice-versa. | |strongly
Effects of | | | |advocated.
changes of | |Struggle for existence; | |
food. | |stronger devour the | |Natural
|Domesti- |weaker. Competition | |selection.
Effects of |cation |stated in case of ai or |Species are |
domesti- |briefly |sloth. Balance of |"different |Sexual
cation. |referred to. |nature. |modifi- |selection.
| | |cations of |
Effects of |Effects of |Effects of use and |one and the |Effects of
use. (The |use: |disuse, discussed at |same type." |use and
only examples|characters |length. | |disuse (in
given are the|produced by | | |some
callosities |their own |Vestigial structures the| |cases).
on legs of |exertions in |remains of organs | |
camel, of |consequence |actively used by | |
baboon, and |of their |ancestors of present | |
the |desires, |forms. | |
thickening by|aversions, | | |
use of soles |lust, hunger,|New wants or necessities| |
on man's |and security.|induced by changes of | |
feet.) | |climate, habitat, etc., | |
|Sexual |result in production of | |
|selection, |new propensities, new | |
|law of |habits, and functions. | |
|battle. | | |
| |Change of habits | |
|Protective |originate organs; change| |
|mimicry. |of functions create new | |
| |organs; formation of new| |
|Origin of |habits precede the | |
|organs before|origin of new or | |
|development |modification of organs | |
|of their |already formed. | |
|functions. | | |
| |Geographical isolation | |Isolation
|Inheritance |suggested as a factor in| |"an
|of acquired |case of man. | |important
|characters | | |element."
|(vaguely |Swamping effects of | |
|stated). |crossing. | |
| | | |
|Instincts |Lamarck's definition of | |
|result of |species the most | |
|imitation. |satisfactory yet stated.| |
| | | |
|Opposed |Inheritance of acquired | |Inheritance
|preformation |characters. | |of acquired
|views of | | |characters.
|Haller and |Instinct the result of | |
|Bonnet. |inherited habits. | |
| | | |
| |Opposed preformation | |
| |views; epigenesis | |
| |definitely stated and | |
| |adopted. | |
| | | |
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