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 Vertèbres (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]