Evolution, Old & New / Or, the Theories of Buffon, Dr. Erasmus Darwin and Lamarck, / as compared with that of Charles Darwin

by Samuel Butler

"Many ingenious philosophers have found so great difficulty in conceiving the manner of the reproduction of animals, that they have supposed all the numerous progeny to have existed in miniature in the animal originally created; and that these infinitely minute forms are only evolved or distended, as the embryon increases in the womb. This idea, besides its being unsupported by any analogy we are acquainted with, ascribes a greater tenuity to organized matter than we can readily admit; as these included embryons are supposed each of them to consist of the various and complicate parts of animal bodies, they must possess a much greater degree of minuteness than that which was ascribed to the devils which tempted St. Anthony, of whom 20,000 were said to have been able to dance a saraband on the point of the finest needle without incommoding one another."[172]

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"I conceive the primordium or rudiment of the embryon as secreted from the blood of the parent to consist of a simple living filament as a muscular fibre; which I suppose to be an extremity of a nerve of locomotion, as a fibre of the retina is an extremity of a nerve of sensation; as, for instance, one of the fibrils which compose the mouth of an absorbent vessel. I suppose this living filament of whatever form it may be, whether sphere, cube, or cylinder, to be endued with the capability of being excited into action by certain kinds of stimulus. By the stimulus of the surrounding fluid in which it is received from the male it may bend into a ring, and thus form the beginning of a tube. Such moving filaments and such rings are described by those who have attended to microscopic animalculæ. This living ring may now embrace or absorb a nutritive particle of the fluid in which it swims; and by drawing it into its pores, or joining it by compression to its extremities, may increase its own length or crassitude, and by degrees the living ring may become a living tube.

"With this new organization, or accretion of parts, new kinds of irritability may commence; for so long as there was but one living organ it could only be supposed to possess irritability; since sensibility may be conceived to be an extension of the effect of irritability over the rest of the system. These new kinds of irritability and of sensibility in consequence of new organization appear from variety of facts in the more mature animals; thus ... the lungs must be previously formed before their exertions to obtain fresh air can exist; the throat, or œsophagus, must be formed previous to the sensation or appetites of hunger and thirst, one of which seems to reside at the upper end and the other at the lower end of that canal."[173]

It seems to me Dr. Darwin is wrong in supposing that the organ must have preceded the power to use it. The organ and its use—the desire to do and the power to do—have always gone hand in hand, the organism finding itself able to do more according as it advanced its desires, and desiring to do more simultaneously with any increase in power, so that neither appetency nor organism can claim precedence, but power and desire must be considered as Siamese twins begotten together, conceived together, born together, and inseparable always from each other. At the same time they are torn by mutual jealousy; each claims, with some vain show of reason, to have been the elder brother; each intrigues incessantly from the beginning to the end of time to prevent the other from outstripping him; each is in turn successful, but each is doomed to death with the extinction of the other.

"So inflamed tendons and membranes, and even bones, acquire new sensations; and the parts of mutilated animals, as of wounded snails and polypi and crabs, are reproduced; and at the same time acquire sensations adapted to their situation. Thus when the head of a snail is reproduced after decollation with a sharp razor, those curious telescopic eyes are also reproduced, and acquire their sensibility to light, as well as their adapted muscles for retraction on the approach of injury.

"With every change, therefore, of organic form or addition of organic parts, I suppose a new kind of irritability or of sensibility to be produced; such varieties of irritability or of sensibility exist in our adult state in the glands; every one of which is furnished with an irritability or a taste or appetency, and a consequent mode of action peculiar to itself.

"In this manner I conceive the vessels of the jaws to produce those of the teeth; those of the fingers to produce the nails; those of the skin to produce the hair; in the same manner as afterwards, about the age of puberty, the beard and other great changes in the form of the body and disposition of the mind are produced in consequence of new developments; for, if the animal is deprived of these developments, those changes do not take place. These changes I believe to be formed not by elongation or distension of primeval stamina, but by apposition of parts; as the mature crab fish when deprived of a limb, in a certain space of time, has power to regenerate it; and the tadpole puts forth its feet after its long exclusion from the spawn, and the caterpillar in changing into a butterfly acquires a new form with new powers, new sensations, and new desires."[174]

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"From hence I conclude that with the acquisition of new parts, new sensations and new desires, as well as new powers are produced; and this by accretion to the old ones and not by distension of them. And finally, that the most essential parts of the system, as the brain for the purpose of distributing the powers of life, and the placenta for the purpose of oxygenating the blood, and the additional absorbent vessels, for the purpose of acquiring aliment, are first formed by the irritations above mentioned, and by the pleasurable sensations attending those irritations, and by the exertions in consequence of painful sensations similar to those of hunger and suffocation. After these an apparatus of limbs for future uses, or for the purpose of moving the body in its present natant state, and of lungs for future respiration, and of testes for future reproduction, are formed by the irritations and sensations and consequent exertions of the parts previously existing, and to which the new parts are to be attached.[175]