Chapter 10

LAMARCK'S OPINIONS ON GENERAL PHYSIOLOGY AND BIOLOGY

Lamarck died before the rise of the sciences of morphology, embryology, and cytology. As to palæontology, which he aided in founding, he had but the slightest idea of the geological succession of life-forms, and not an inkling of the biogenetic law or recapitulation theory. Little did he know or foresee that the main and strongest support of his own theory was to be this same science of the extinct forms of life. Yet it is a matter of interest to know what were his views or opinions on the nature of life; whether he made any suggestions bearing on the doctrine of the unity of nature; whether he was a vitalist or not; and whether he was a follower of Haller and of Bonnet,[107] as was Cuvier, or pronounced in favor of epigenesis.

We know that he was a firm believer in spontaneous generation, and that he conceived that it took place not only in the origination of his primeval germs or _ébauches_, but at all later periods down to the present day.

Yet Lamarck accepted Harvey's doctrine, published in 1651, that all living beings arose from germs or eggs.[108]

He must have known of Spallanzani's experiments, published in 1776, even if he had not read the writings of Treviranus (1802-1805), both of whom had experimentally disproved the theory of the spontaneous generation of animalcules in putrid infusions, showing that the lowest organisms develop only from germs.

The eighteenth century, though one of great intellectual activity, was, however, as regards cosmology, geology, general physiology or biology, a period of groping in the dim twilight, when the whole truth or even a part of it was beyond the reach of the greatest geniuses, and they could only seize on half-truths. Lamarck, both a practical botanist, systematic zoölogist, and synthetic philosopher, had done his best work before the rise of the experimental and inductive methods, when direct observation and experiments had begun to take the place of vague _à priori_ thinking and reasoning, so that he labored under a disadvantage due largely to the age in which he lived.

Only the closing years of the century witnessed the rise of the experimental methods in physics and chemistry, owing to the brilliant work of Priestley and of Lavoisier. The foundations of general physiology had been laid by Haller,[109] those of embryology to a partial extent by Wolff,[110] Von Baer's work not appearing until 1829, the year in which Lamarck died.

_Spontaneous Generation._--Lamarck's views on spontaneous generation are stated in his _Recherches sur l'Organisation des Corps vivans_ (1802). He begins by referring to his statement in a previous work[111] that life may be suspended for a time and then go on again.

"Here I would remark it (life) can be produced (_préparée_) both by an organic act and by nature herself, without any act of this kind, in such a way that certain bodies without possessing life can be prepared to receive it, by an impression _which indicates in these bodies the first traces of organization_."

We will not enter upon an exposition of his views on the nature of sexual generation and of fecundation, the character of his _vapeur subtile_ (_aura vitalis_) which he supposes to take an active part in the act of fertilization, because the notion is quite as objectionable as that of the vital force which he rejects. He goes on to say, however, that we cannot penetrate farther into the wonderful mystery of fecundation, but the opinions he expresses lead to the view that "nature herself imitates her procedures in fecundation in another state of things, without having need of the union or of the products of any preëxistent organization."

He proceeds to observe that in the places where his _aura vitalis_, or subtle fluid, is very abundant, as in hot climates or in heated periods, and especially in humid places, life seems to originate and to multiply itself everywhere and with a singular rapidity.

"In this high temperature the higher animals and mankind develop and mature more rapidly, and diseases run their courses more swiftly; while on the other hand these conditions are more favorable to the simpler forms of life, for the reason that in them the orgasm and irritability are entirely dependent on external influences, and all plants are in the same case, because heat, moisture, and light complete the conditions necessary to their existence.

"Because heat is so advantageous to the simplest animals, let us examine whether there is not occasion for believing that it can itself form, with the concourse of favorable circumstances, the first germs of animal life.

"_Nature necessarily forms generations, spontaneous or direct, at the extremity of each organic kingdom or where the simplest organic bodies occur._"

This proposition, he allows, is so far removed from the view generally held, that it will be for a long time, and perhaps always, regarded as one of the errors of the human mind.

"I do not," he adds, "ask any one to accord it the least confidence on my word alone. But as surely it will happen, sooner or later, that men on the one hand independent of prejudices even the most widespread, and on the other profound observers of nature, may have a glimpse of this truth, I am very content that we should know that it is of the number of those views which, in spite of the prejudices of my age, I have thought it well to accept."

"Why," he asks, "should not heat and electricity act on certain matters under favorable conditions and circumstances?" He quotes Lavoisier as saying (_Chémie_, i., p. 202) "that God in creating light had spread over the world the principle of organization of feeling and of thought"; and Lamarck suggests that heat, "this mother of generation, this material soul of organized bodies," may be the chief one of the means which nature directly employs to produce in the appropriate kind of matter an act of arrangement of parts, of a primitive germ of organization, and consequently of vitalization analogous to sexual fecundation.

"Not only the direct formation of the simplest living beings could have taken place, as I shall attempt to demonstrate, but the following considerations prove that it is necessary that such germ-formations should be effected and be repeated under favorable conditions, without which the state of things which we observe could neither exist nor subsist."

His argument is that in the lower polyps (the Protozoa) there is no sexual reproduction, no eggs. But they perish (as he strangely thought, without apparently attempting to verify his belief) in the winter. How, he asks, can they reappear? Is it not more likely that these simple organisms are themselves regenerated? After much verbiage and repetition, he concludes:

"We may conceive that the simplest organisms can arise from a minute mass of substances which possess the following conditions--namely, which will have solid parts in a state nearest the fluid conditions, consequently having the greatest suppleness and only sufficient consistence to be susceptible of constituting the parts contained in it. Such is the condition of the most gelatinous organized bodies.

"Through such a mass of substances the subtile and expansive fluids spread, and, always in motion in the milieu environing it, unceasingly penetrate it and likewise dissipate it, arranging while traversing this mass the internal disposition of its parts, and rendering it suitable to continually absorb and to exhale the other environing fluids which are able to penetrate into its interior, and which are susceptible of being contained.

"These other fluids, which are water charged with dissolved (_dissous_) gas, or with other tenuous substances, the atmospheric air, which contains water, etc., I call containable fluids, to distinguish them from subtile fluids, such as caloric, electricity, etc., which no known bodies are believed to contain.

"The containable fluids absorbed by the small gelatinous mass in question remain almost motionless in its different parts, because the non-containable subtile fluids which always penetrate there do not permit it.

"In this way the uncontainable fluids at first mark out the first traces of the simplest organization, and consequently the containable fluids by their movements and their other influences develop it, and with time and all the favorable circumstances complete it."

This is certainly a sufficiently vague and unsatisfactory theory of spontaneous generation. This sort of guess-work and hypothetical reasoning is not entirely confined to Lamarck's time. Have we not, even a century later, examples among some of our biologists, and very eminent ones, of whole volumes of _à priori_ theorizing and reasoning, with scarcely a single new fact to serve as a foundation? And yet this is an age of laboratories, of experimentations and of trained observers. The best of us indulge in far-fetched hypotheses, such as pangenesis, panmixia, the existence of determinants, and if this be so should we not excuse Lamarck, who gave so many years to close observation in systematic botany and zoölogy, for his flights into the empyrean of subtle fluids, containable and uncontainable, and for his invocation of an _aura vitalis_, at a time when the world of demonstrated facts in modern biology was undiscovered and its existence unsuspected?

_The Preëxistence of Germs and the Encasement Theory._--Lamarck did not believe in Bonnet's idea of the "preëxistence of germs." He asks whether there is any foundation for the notion that germs "successively develop in generations, _i.e._ in the multiplication of individuals for the preservation of species," and says:

"I am not inclined to believe it if this preëxistence is taken in a general sense; but in limiting it to individuals in which the unfertilized embryos or germs are formed before generation. I then believe that it has some foundation.--They say with good reason," he adds, "that every living being originates from an egg.... But the eggs being the envelope of every kind of germ, they preëxist in the individuals which produce them, before fertilization has vivified them. The seeds of plants (which are vegetable eggs) actually exist in the ovaries of flowers before the fertilization of these ovaries."[112]

From whom did he get this idea that seeds or eggs are envelopes of all sorts of germs? It is not the "evolution" of a single germ, as, for example, an excessively minute but complete chick in the hen's egg, in the sense held by Bonnet. Who it was he does not mention. He evidently, however, had the Swiss biologist in mind, who held that all living things proceed from preëxisting germs.[113]

Whatever may have been his views as to the germs in the egg before fertilization, we take it that he believed in the epigenetic development of the plant or animal after the seed or egg was once fertilized.[114]

Lamarck did not adopt the encasement theory of Swammerdam and of Heller. We find nothing in Lamarck's writings opposed to epigenesis. The following passage, which bears on this subject, is translated from his _Mémoires de Physique_ (p. 250), where he contrasts the growth of organic bodies with that of minerals.

"The body of this living being not having been formed by _juxtaposition_, as most mineral substances, that is to say, by the external and successive apposition of particles aggregated _en masse_ by attraction, but essentially formed by generation, in its principle, it has then grown by intussusception--namely, by the introduction, the transportation, and the internal apposition of molecules borne along and deposited between its parts; whence have resulted the successive developments of parts which compose the body of this living individual, and from which afterwards also result the repairs which preserve it during a limited time."

Here, as elsewhere in his various works, Lamarck brings out the fact, for the first time stated, that all material things are either non-living or mineral, inorganic; or living, organic. A favorite phrase with him is living bodies, or, as we should say, organisms. He also is the first one to show that minerals increase by juxtaposition, while organisms grow by intussusception.

No one would look in his writings for an idea or suggestion of the principle of differentiation of parts or organs as we now understand it, or for the idea of the physiological division of labor; these were reserved for the later periods of embryology and morphology.

_Origin of the First Vital Function._--We will now return to the germ. After it had begun spontaneous existence, Lamarck proceeds to say:

"Before the containable fluids absorbed by the small, jelly-like mass in question have been expelled by the new portions of the same fluids which reach there, they can then deposit certain of the contained fluids they carry along, and the movements of the contained fluids may apply these substances to the containing parts of the newly organized microscopic being. In this way originates the first of the vital functions which becomes established in the simplest organism, _i.e._, nutrition. The environing containable fluids are, then, for the living body of very great simplicity, a veritable chyle entirely prepared by nature.

"Mutilation cannot operate without gradually increasing the consistence of the parts contained within the minute new organism and without extending its dimensions. Hence soon arose the second of the vital functions, _growth or internal development_."

_First Faculty of Animal Nature._--Then gradually as the continuity of this state of things within the same minute living mass in question increases the consistence of its parts enclosed within and extends its dimensions, a vital orgasm, at first very feeble, but becoming progressively more intense, is formed in these enclosed parts and renders them susceptible of _reaction_ against the slight impression of the fluids in motion which they contain, and at the same time renders them capable of contraction and of distention. Hence the origin of _animal irritability_ and the basis of feeling, which is developed wherever a nervous fluid, susceptible of locating the effects in one of several special centres, can be formed.

"Scarcely will the living corpuscle, newly animalized, have received any increase in consistence and in dimensions of the parts contained, when, as the result of the organic movement which it enjoys, it will be subjected to successive changes and losses of its substance.

"It will then be obliged to take nourishment not only to obtain any development whatever, but also to preserve its individual existence, because it is necessary that it repair its losses under penalty of its destruction.

"But as the individual in question has not yet any special organ for nutrition, it therefore absorbs by the pores of its internal surface the substance adapted for its nourishment. Thus the first mode of taking food in a living body so simple can be no other than by absorption or a sort of suction, which is accomplished by the pores of its outer surface.

"This is not all; up to the present time the animalized corpuscle we are considering is still only a primitive animalcule because it as yet has no special organ. Let us see then how nature will come to furnish it with any primitive special organ, and what will be the organ that nature will form before any others, and which in the simplest animal is the only one constantly found; this is the alimentary canal, the principal organ of digestion common to all except colpodes, vibrios, proteus (amoeba), volvoces, monads, etc.

"This digestive canal is," he says--proceeding with his _à priori_ morphology--"a little different from that of this day, produced by contractions of the body, which are stronger in one part of the body than in another, until a little crease is produced on the surface of the body. This furrow or crease will receive the food. Insensibly this little furrow by the habit of being filled, and by the so frequent use of its pores, will gradually increase in depth; it will soon assume the form of a pouch or of a tubular cavity with porous walls, a blind sac, or with but a single opening. Behold the primitive alimentary canal created by nature, the simplest organ of digestion."

In like _à priori_ manner he describes the creation of the faculty of reproduction. The next organ, he says, is that of reproduction due to the regenerative faculty. He describes fission and budding. Finally (p. 122) he says:

"Indeed, we perceive that if the first germs of living bodies are all formed in one day in such great abundance and facility under favorable circumstances, they ought to be, nevertheless, by reason of the antiquity of the causes which make them exist, the most ancient organisms in nature."

In 1794 he rejected the view once held of a continuous chain of being, the _échelle des êtres_ suggested by Locke and by Leibnitz, and more fully elaborated by Bonnet, from the inorganic to the organic worlds, from minerals to plants, from plants to polyps (our Infusoria), polyps to worms, and so on to the higher animals. He, on the contrary, affirms that nature makes leaps, that there is a wide gap between minerals and living bodies, that everything is not gradated and shaded into each other. One reason for this was possibly his strange view, expressed in 1794, that all brute bodies and inorganic matters, even granite, were not formed at the same epoch but at different times, and were derived from organisms.[115]

The mystical doctrine of a vital force was rife in Lamarck's time. The chief starting point of the doctrine was due to Haller, and, as Verworn states, it is a doctrine which has confused all physiology down to the middle of the present century, and even now emerges again here and there in varied form.[116]

Lamarck was not a vitalist. Life, he says,[117] is usually supposed to be a particular being or entity; a sort of principle whose nature is unknown, and which possesses living bodies. This notion he denies as absurd, saying that life is a very natural phenomenon, a physical fact; in truth a little complicated in its principles, but not in any sense a particular or special being or entity.

He then defines life in the following words: "Life is an order and a state of things in the parts of every body possessing it, which permits or renders possible in it the execution of organic movement, and which, so long as it exists, is effectively opposed to death. Derange this order and this state of things to the point of preventing the execution of organic movement, or the possibility of its reëstablishment, then you cause death." Afterwards, in the _Philosophie zoologique_, he modifies this definition, which reads thus: "Life, in the parts of a body which possesses it, is an order and a state of things which permit organic movements; and these movements, which constitute active life, result from the action of a stimulating cause which excites them."[118]

For the science of all living bodies Lamarck proposed the word "Biology," which is so convenient a term at the present day. The word first appears in the preface to the _Hydrogéologie_, published in 1802. It is worthy of note that in the same year the same word was proposed for the same science by G. R. Treviranus as the title of a work, _Biologie, der Philosophie der lebenden Natur_, published in 1802-1805 (vols. i.-vi., 1802-1822), the first volume appearing in 1802.

In the second part of the _Philosophie zoologique_ he considers the physical causes of life, and in the introduction he defines nature as the _ensemble_ of objects which comprise: (1) All existing physical bodies; (2) the general and special laws which regulate the changes of condition and situation of these bodies; (3) finally, the movement everywhere going on among them resulting in the wonderful order of things in nature.

To regard nature as eternal, and consequently as having existed from all time, is baseless and unreasonable. He prefers to think that nature is only a result, "whence, I suppose, and am glad to admit, a first cause, in a word, a supreme power which has given existence to nature, which has made it as a whole what it is."

As to the source of life in bodies endowed with it, he considers it a problem more difficult than to determine the course of the stars in space, or the size, masses, and movements of the planets belonging to our solar system; but, however formidable the problem, the difficulties are not insurmountable, as the phenomena are purely physical--_i.e._, essentially resulting from acts of organization.

After defining life, in the third chapter (beginning vol. ii.) he treats of the exciting cause of organic movements. This exciting cause is foreign to the body which it vivifies, and does not perish, like the latter. "This cause resides in invisible, subtile, expansive, ever-active fluids which penetrate or are incessantly developed in the bodies which they animate." These subtile fluids we should in these days regard as the physico-chemical agents, such as heat, light, electricity.

What he says in the next two chapters as to the "orgasme" and irritability excited by the before-mentioned exciting cause may be regarded as a crude foreshadowing of the primary properties of protoplasm, now regarded as the physical basis of life--_i.e._, contractility, irritability, and metabolism. In Chapter VI. Lamarck discusses direct or spontaneous generation in the same way as in 1802. In the following paragraph we have foreshadowed the characteristic qualities of the primeval protoplasmic matter fitted to receive the first traces of organization and life:

"Every mass of substance homogeneous in appearance, of a gelatinous or mucilaginous consistence, whose parts, coherent among themselves, will be in the state nearest fluidity, but will have only a consistence sufficient to constitute containing parts, will be the body most fitted to receive the first traces of organization and life."

In the third part of the _Philosophie zoologique_ Lamarck considers the physical causes of feeling--_i.e._, those which form the productive force of actions, and those giving rise to intelligent acts. After describing the nervous system and its functions, he discusses the nervous fluid. His physiological views are based on those of Richerand's _Physiologie_, which he at times quotes.

Lamarck's thoughts on the nature of the nervous fluid (_Recherches sur le fluide nerveux_) are curious and illustrative of the gropings after the truth of his age.

He claims that the supposed nervous fluid has much analogy to the electric, that it is the _feu éthéré_ "animalized by the circumstances under which it occurs." In his _Recherches sur l'organisation des corps vivans_ (1802) he states that, as the result of changes continually undergone by the principal fluids of an animal, there is continually set free in a state of _feu fixé_ a special fluid, which at the instant of its disengagement occurs in the expansive state of the caloric, then becomes gradually rarefied, and insensibly arrives at the state of an extremely subtile fluid which then passes along the smallest nervous ramifications in the substance of the nerve, which is a very good conductor for it. On its side the brain sends back the subtile fluid in question along the nerves to the different organs.

In the same work (1802) Lamarck defines thought as a physical act taking place in the brain. "This act of thinking gives rise to different displacements of the subtile nervous fluid and to different accumulations of this fluid in the parts of the brain where the ideas have been traced." There result from the flow of the fluid on the conserved impressions of ideas, special movements which portions of this fluid acquire with each impression, which give rise to compounds by their union producing new impressions on the delicate organ which receives them, and which constitute abstract ideas of all kinds, also the different acts of thought.

All the acts which constitute thought are the comparisons of ideas, both simple and complex, and the results of these comparisons are judgments.

He then discusses the influence of the nervous fluid on the muscles, and also its influence considered as the cause of feeling (_sentiment_). Finally he concludes that _feu fixé_, caloric, the nervous fluid, and the electric fluid "are only one and the same substance occurring in different states."

FOOTNOTES:

[107] Charles Bonnet (1720-1793), a Swiss naturalist, is famous for his work on Aphides and their parthenogenetic generation, on the mode of reproduction in the Polyzoa, and on the respiration of insects. After the age of thirty-four, when his eyesight became impaired, he began his premature speculations, which did not add to his reputation. Judging, however, by an extract from his writings by D'Archiac (_Introduction à l'Étude de la Paléontologie stratigraphique_, ii., p. 49), he had sound ideas on the theory of descent, claiming that "la diversité et la multitude des conjunctions, peut-être même la diversité des climats et des nourritures, ont donné naissance à de nouvelles espèces ou à des individus intermédiaires" (_Oeuvres d'Hist. nat. et de Philosophie_, in-8vo, p. 230, 1779).

[108] See his remark: "_On a dit avec raison que tout ce qui a vie provient d'un auf_" (_Mémoires de Physique_, etc., 1797, p. 272). He appears, however, to have made the simplest organisms exceptions to this doctrine.

[109] _Elementa physiologiae corporis humani_, iv. Lausanne, 1762.

[110] _Theoria generationis_, 1774.

[111] _Mémoires de Physique_, (1797), p. 250.

[112] _Mémoires de Physique_, etc. (1797), p. 272.

[113] Huxley's "Evolution in Biology" (_Darwiniana_, p. 192), where be quotes from Bonnet's statements, which "bear no small resemblance to what is understood by evolution at the present day."

[114] Buffon did not accept Bonnet's theory of preëxistent germs, but he assumed the existence of "_germes accumulés_" which reproduced parts or organs, and for the production of organisms he imagined "_molécules organiques_." Réaumur had previously (1712) conjectured that there were "_germes cachés et accumulés_" to account for the regeneration of the limbs of the crayfish. The ideas of Bonnet on germs are stated in his _Mémoires sur les Salamandres_ (1777-78-80) and in his _Considérations sur les corps organisés_ (1762.)

[115] _Mémoires de Physique_, etc., pp. 318, 319, 324-359. Yet the idea of a sort of continuity between the inorganic and the organic world is expressed by Verworn.

[116] _General Physiology_ (English trans., 1899, p. 17). In France vitalism was founded by Bordeu (1722-1766), developed further by Barthez (1734-1806) and Chaussier (1746-1828), and formulated most distinctly by Louis Dumas (1765-1813). Later vitalists gave it a thoroughly mystical aspect, distinguishing several varieties, such as the _nisus formativus_ or formative effort, to explain the forms of organisms, accounting for the fact that from the egg of a bird, a bird and no other species always develops (_l. c._, p. 18).

[117] _Recherches sur l'organisation des corps vivans_ (1802), p. 70. The same view was expressed in _Mémoires de physique_ (1797), pp. 254-257, 386.

[118] Here might be quoted for comparison other famous definitions of life:

"Life is the sum of the functions by which death is resisted."--Bichat.

"Life is the result of organization."--(?)

"Life is the principle of individuation."--Coleridge ex. Schelling.

"Life is the twofold internal movement of composition and decomposition, at once general and continuous."--De Blainville, who wisely added that there are "two fundamental and correlative conditions inseparable from the living being--an organism and a medium."

"Life is the continuous adjustment of internal relations to external relations."--Herbert Spencer.