Lamarck, the Founder of Evolution Part 36

Without translating more of this remarkable book, which is very rare, much less known than the _Philosophie zoologique_, the spirit of the remainder may be imagined from the foregoing extracts.

The author refers to the numerous evils resulting from ignorance, false knowledge, lack of judgment, abuse of power, demonstrating the necessity of our confining ourselves within the circle of the objects presented by nature, and never to go beyond them if we do not wish to fall into error, because the profound study of nature and of the organization of man alone, and the exact observation of facts alone, will reveal to us "the truths most important for us to know," in order to avoid the vexations, the perfidies, the injustices, and the oppressions of all sorts, and "incalculable disorders" which arise in the social body. In this way only shall we discover and acquire the means of obtaining the enjoyment of the advantages which we have a right to expect from our state of civilization. The author endeavors to state what science can and should render to society. He dwells on the sources from which man has drawn the knowledge which he possesses, and from which he can obtain many others--sources the totality of which const.i.tutes for him the field of realities.

Lamarck also in this work has built up a system for moral philosophy.

Self-love, he says, perfectly regulated, gives rise:

1. To moral force which characterizes the laborious man, so that the length and difficulties of a useful work do not repel him.

2. To the courage of him who, knowing the danger, exposes himself when he sees that this would be useful.

3. To love of wisdom.

Wisdom, according to Lamarck, consists in the observance of a certain number of rules or virtues. These we cite in a slightly abridged form.

Love of truth in all things; the need of improving one's mind; moderation in desires; decorum in all actions; a wise reserve in unessential wants; indulgence, toleration, humanity, good will towards all men; love of the public good and of all that is necessary to our fellows; contempt for weakness; a kind of severity towards one's self which preserves us from that mult.i.tude of artificial wants enslaving those who give up to them; resignation and, if possible, moral impa.s.sibility in suffering reverses, injustices, oppression, and losses; respect for order, for public inst.i.tutions, civil authorities, laws, morality, and religion.

The practice of these maxims and virtues, says Lamarck, characterizes true philosophy.

And it may be added that no one practised these virtues more than Lamarck. Like Cuvier's, his life was blameless, and though he lived a most retired life, and was not called upon to fill any public station other than his chair of zoology at the Jardin des Plantes, we may feel sure that he had the qualities of courage, independence, and patriotism which would have rendered such a career most useful to his country.

As Bourguin eloquently a.s.serts: "Lamarck was the brave man who never deserted a dangerous post, the laborious man who never hesitated to meet any difficulty, the investigating spirit, firm in his convictions, tolerant of the opinions of others, the simple man, moderate in all things, the enemy of weakness, devoted to the public good, imperturbable under the attaints of fortune, of suffering, and of unjust and pa.s.sionate attacks."

FOOTNOTES:

[198] Mathias Duval: "Le transformiste francais Lamarck," _Bulletin de la Societe d'Anthropologie de Paris_, xii., 1889, p. 345.

[199] _Philosophie zoologique_, p. 56.

[200] _Loc. cit._, i., p. 113.

[201] _Loc. cit._, i., p. 361.

[202] _Loc. cit._, ii., p. 465.

[203] _Systeme a.n.a.lytique des Connaissances de l'Homme_, etc.

CHAPTER XX

THE RELATIONS BETWEEN LAMARCKISM AND DARWINISM; NEOLAMARCKISM

Since the appearance of Darwin's _Origin of Species_, and after the great naturalist had converted the world to a belief in the general doctrine of evolution, there has arisen in the minds of many working naturalists a conviction that natural selection, or Darwinism as such, is only one of other evolutionary factors; while there are some who entirely reject the selective principle. Darwin, moreover, a.s.sumed a tendency to fortuitous variation, and did not attempt to explain its cause. Fully persuaded that he had discovered the most efficient and practically sole cause of the origin of species, he carried the doctrine to its extreme limits, and after over twenty years of observation and experiment along this single line, pushing entirely aside the Erasmus-Darwin and Lamarckian factors of change of environment, though occasionally acknowledging the value of use and disuse, he triumphantly broke over all opposition, and lived to see his doctrine generally accepted. He had besides the support of some of the strongest men in science: Wallace in a twin paper advocated the same views; Spencer, Lyell, Huxley, Hooker, Haeckel, Bates, Semper, Wyman, Gray, Leidy, and other representative men more or less endorsed Darwin's views, or at least some form of evolution, and owing largely to their efforts in scientific circles and in the popular press, the doctrine of descent rapidly permeated every avenue of thought and became generally accepted.

Meanwhile, the general doctrine of evolution thus proved, and the "survival of the fittest" an accomplished fact, the next step was to ascertain "how," as Cope asked, "the fittest originated?" It was felt by some that natural selection alone was not adequate to explain the first steps in the origin of genera, families, orders, cla.s.ses, and branches or phyla. It was perceived by some that natural selection by itself was not a _vera causa_, an efficient agent, but was pa.s.sive, and rather expressed the results of the operations of a series of factors. The transforming should naturally precede the action of the selective agencies.

We were, then, in our quest for the factors of organic evolution, obliged to fall back on the action of the physico-chemical forces such as light, or its absence, heat, cold, change of climate; and the physiological agencies of food, or in other words on changes in the physical environment, as well as in the biological environment. Lamarck was the first one who, owing to his many years' training in systematic botany and zoology, and his philosophic breadth, had stated more fully and authoritatively than any one else the results of changes in the action of the primary factors of evolution. Hence a return on the part of many in Europe, and especially in America, to Lamarckism or its modern form, Neolamarckism. Lamarck had already, so far as he could without a knowledge of modern morphology, embryology, cytology, and histology, suggested those fundamental principles of transformism on which rests the selective principle.

Had his works been more accessible, or, where available, more carefully read, and his views more fairly represented; had he been favored in his lifetime by a single supporter, rather than been unjustly criticised by Cuvier, science would have made more rapid progress, for it is an axiomatic truth that the general acceptance of a working evolutionary theory has given a vast impetus to biology.

We will now give a brief historical summary of the history of opinion held by Lamarckians regarding the causes of the "origin of the fittest,"

the rise of variations, and the appearance of a population of plant and animal forms sufficiently extensive and differentiated to allow for the play of the compet.i.tive forces, and of the more pa.s.sive selective agencies which began to operate in pre-cambrian times, or as soon as the earth became fitted for the existence of living beings.

The first writer after Lamarck to work along the lines he laid down was Mr. Herbert Spencer. In 1866-71, in his epochal and remarkably suggestive _Principles of Biology_, the doctrine of use and disuse is implicated in his statements as to the effects of motion on structure in general;[204] and in his theory as to the origin of the notochord, and of the segmentation of the vertebral column and the segmental arrangement of the muscles by muscular strains,[205] he laid the foundations for future work along this line. He also drew attention in the same work to the complementary development of parts, and likewise instanced the decreased size of the jaws in the civilized races of mankind, as a change not accounted for by the natural selection of favorable variations.[206] In fact, this work is largely based on the Lamarckian principles, as affording the basis for the action of natural selection, and thirty years later we find him affirming: "The direct action of the medium was the primordial factor of organic evolution."[207] In his well-known essay on "The Inadequacy of Natural Selection" (1893) the great philosopher, with his accustomed vigor and force, criticises the arguments of those who rely too exclusively on Darwinism alone, and especially Neodarwinism, as a sufficient factor to account for the origin of special structures as well as species.

The first German author to appreciate the value of the Lamarckian factors was that fertile and comprehensive philosopher and investigator Ernst Haeckel, who also harmonized Lamarckism and Darwinism in these words:

"We should, on account of the grand proofs just enumerated, have to adopt Lamarck's Theory of Descent for the explanation of biological phenomena, even if we did not possess Darwin's Theory of Selection.

The one is so completely and _directly proved_ by the other, and established by mechanical causes, that there remains nothing to be desired. The laws of _Inheritance_ and _Adaptation_ are universally acknowledged physiological facts, the former traceable to propagation, the latter to the _nutrition_ of organisms. On the other hand, the _struggle for existence_ is a _biological_ fact, which with mathematical necessity follows from the general disproportion between the average number of organic individuals and the numerical excess of their germs."[208]

A number of American naturalists at about the same date, as the result of studies in different directions, unbia.s.sed by a too firm belief in the efficacy of natural selection, and relying on the inductive method alone, worked away at the evidence in favor of the primary factors of evolution along Lamarckian lines, though quite independently, for at first neither Hyatt nor Cope had read Lamarck's writings.

In 1866 Professor A. Hyatt published the first of a series of cla.s.sic memoirs on the genetic relations of the fossil cephalopods. His labors, so rich in results, have now been carried on for forty years, and are supplemented by careful, prolonged work on the sponges, on the tertiary sh.e.l.ls of Steinheim, and on the land sh.e.l.ls of the Hawaiian Islands.

His first paper was on the parallelism between the different stages of life in the individual and those of the ammonites, carrying out D'Orbigny's discovery of embryonic, youthful, adult, and old-age stages in ammonites,[209] and showing that these forms are due to an acceleration of growth in the mature forms, and a r.e.t.a.r.dation in the senile forms.

In a memoir on the "Biological Relations of the Jura.s.sic Ammonites,"[210] he a.s.signs the causes of the progressive changes in these forms, the origination of new genera, and the production of young, mature, and senile forms to "the favorable nature of the physical surroundings, primarily producing characteristic changes which become perpetuated and increased by inheritance within the group."

The study of the modifications of the tertiary forms of Planorbis at Steinheim, begun by Hilgendorf, led among others (nine in all) to the following conclusions:

"First, that the unsymmetrical spiral forms of the sh.e.l.ls of these and of all the Mollusca probably resulted from the action of the laws of heredity, modified by gravitation.

"Second, that there are many characteristics in these sh.e.l.ls and in other groups, which are due solely to the uniform action of the physical influence of the immediate surroundings, varying with every change of locality, but constant and uniform within each locality.

"Third, that the Darwinian law of Natural Selection does not explain these relations, but applies only to the first stages in the establishment of the differences between forms or species in the same locality. That its office is to fix these in the organization and bring them within the reach of the laws of heredity."

These views we find reiterated in his later palaeontological papers.

Hyatt's views on acceleration were adopted by Neumayr.[211] Waagen,[212]

from his studies on the Jura.s.sic cephalopods, concludes that the factors in the evolution of these forms were changes in external conditions, geographical isolation, compet.i.tion, and that the fundamental law was not that of Darwin, but "the law of development." Hyatt has also shown that at first evolution was rapid. "The evolution is a purely mechanical problem in which the action of the habitat is the working agent of all the major changes; first acting upon the adult stages, as a rule, and then through heredity upon the earlier stages in successive generations." He also shows that as the primitive forms migrated and occupied new, before barren, areas, where they met with new conditions, the organisms "changed their habits and structures rapidly to accord with these new conditions."[213]

While the palaeontological facts afford complete and abundant proofs of the modifying action of changes in the environment, Hyatt, in 1877, from his studies on sponges,[214] shows that the origin of their endless forms "can only be explained by the action of physical surroundings directly working upon the organization and producing by such direct action the modifications or common variations above described."

Mr. A. Aga.s.siz remarks that the effect of the nature of the bottom of the sea on sponges and rhizopods "is an all-important factor in modifying the organism."[215]

While Hyatt's studies were chiefly on the ammonites, molluscs, and existing sponges, Cope was meanwhile at work on the batrachians. His _Origin of Genera_ appeared shortly after Hyatt's first paper, but in the same year (1866). This was followed by a series of remarkably suggestive essays based on his extensive palaeontological work, which are in part reprinted in his _Origin of the Fittest_ (1887); while in his epoch-making book, _The Primary Factors of Organic Evolution_ (1896), we have in a condensed shape a clear exposition of some of the Lamarckian factors in their modern Neolamarckian form.

In the Introduction, p. 9, he remarks:

"In these papers by Professor Hyatt and myself is found the first attempt to show by concrete examples of natural taxonomy that the variations that result in evolution are not multifarious or promiscuous, but definite and direct, contrary to the method which seeks no origin for variations other than natural selection. In other words, these publications const.i.tute the first essays in systematic evolution that appeared. By the discovery of the paleontologic succession of modifications of the articulations of the vertebrate, and especially mammalian, skeleton, I first furnished an actual demonstration of the reality of the Lamarckian factor of use, or motion, as friction, impact, and strain, as an efficient cause of evolution."[216]

The discussion in Cope's work of kinetogenesis, or of the effects of use and disuse, affords an extensive series of facts in support of these factors of Lamarck's. As these two books are accessible to every one, we need only refer the reader to them as storehouses of facts bearing on Neolamarckism.

The present writer, from a study of the development and anatomy of Limulus and of Arthropod ancestry, was early (1870)[217] led to adopt Lamarckian views in preference to the theory of Natural Selection, which never seemed to him adequate or sufficiently comprehensive to explain the origin of variations.

In the following year,[218] from a study of the insects and other animals of Mammoth Cave, we claimed that "the characters separating the genera and species of animals are those inherited from adults, modified by their physical surroundings and adaptations to changing conditions of life, inducing certain alterations in parts which have been transmitted with more or less rapidity, and become finally fixed and habitual."