The World's Greatest Books [Volumes 1-15, 17-20]

IV.—Epigenesis or Evolution?

The derivative origin of species, then, being at present the most admissible one, and the retrospective survey of such species showing convergence, as time recedes, to more simplified or generalised organisations, the result to which the suggested train of thought inevitably leads is very analogous in each instance. If to kosmos or the mundane system have been allotted powers equivalent to the development of the several grades of life, may not the demonstrated series of conversions of force have also included that into the vital form?

In the last century, physiologists were divided as to the principle guiding the work of organic development.

The "evolutionists" contended that the new being preexisted in a complete state of formation, needing only to be vivified by impregnation in order to commence the series of expansions or disencasings, culminating in the independent individual.

The "epigenesists" held that both the germ and its subsequent organs were built up of juxtaposed molecules according to the operation of a developmental force, or "nisus formations."

At the present day the question may seem hardly worth the paper on which it is referred to. Nevertheless, "pre-existence of germs" and evolution are logically inseparable from the idea of species by primary miraculously-created individuals. Cuvier, therefore, maintained both as firmly as did Haller. In the debates of 1830 I remained the thrall of that dogma in regard to the origin of single-celled organisms whether in or out of body. Every result of formfaction, I believed, with most physiologists, to be the genetic outcome of a pre-existing "cell." The first was due to miraculous interposition and suspension of ordinary laws; it contained potentially all future possible cells. Cell-development exemplified evolution of pre-existing germs, the progeny of the primary cell. They progagated themselves by self-division, or by "proliferation" of minutes granules or atoms, which, when properly nourished, again multiplied by self-division, and grew to the likeness of the parent cells.

It seems to me more consistent with the present phase of dynamical science and the observed graduations of living things to suppose the sarcode or the "protogenal" jelly-speck should be formable through the concurrence of conditions favouring such combination of their elements, and involving a change of force productive of their contractions and extensions, molecular attractions, and repulsions—and the sarcode has so become, from the period when its irrelative repetitions resulted in the vast indefinite masses of the "eozoon," exemplifying the earliest process of "formification" or organic crystallisation—than that all existing sarcodes or "protogenes" are the result of genetic descent from a germ or cell due to a primary act of miraculous interposition.

I prefer, while indulging in such speculations, to consider the various daily nomogeneously developed forms of protozoal or protistal jellies, sarcodes, and single-celled organisms, to have been as many roots from which the higher grades have ramified than that the origin of the whole organic creation is to be referred, as the Egyptian priests did that of the universe, to a single egg.

Amber or steel, when magnetised, seem to exercise "selection"; they do not attract all substances alike. A speck of protogenal jelly or sarcode, if alive, shows analogous relations to certain substances; but the soft yielding tissue allows the part next the attractive matter to move thereto, and then, by retraction, to draw such matter into the sarcodal mass, which overspreads, dissolves, and assimilates it. The term "living" in the one case is correlative with the term "magnetic" in the other. A man perceives ripe fruit; he stretches out his hand, plucks, masticates, swallows, and digests it.

The question then arises whether the difference between such series of actions in the man and the attractive and assimilative movement of the amæba be greater or less than the difference between these acts of the amæba and the attracting and retaining acts of the magnet.

The question, I think, may be put with some confidence as to the quality of the ultimate reply whether the amæbal phenomena are so much more different, or so essentially different, from the magnetic phenomena than they are from the mammalian phenomena, as to necessitate the invocation of a special miracle for their manifestation. It is analogically conceivable that the same cause which has endowed His world with power convertible into magnetic, electric, thermotic and other forms or modes of force, has also added the conditions of conversion into the vital force.