66

GAPS IN DEVELOPMENT THEORY. 345

aquosity," comparing it to Martinus Scriblerus' method of accounting for the operation of the meat-jack by its inherent "meat-roasting quality." But this is the very error into which they themselves fall when they account for development by the "development capacity." The present business of physiologists is not to rest satisfied with the power of devolopment, or the law of hereditary descent, but to seek to determine what are the separate powers and collocations involved in the process. In such investigations they need to attend, as Bacon recommended, to the " necessary rejections and exclusions," or, as Whewell expresses it, "to the decomposition of facts."

Some, I find, are now calling in a power of Pangenesis common to all matter. I do not deny, a priori, the existence of such a power: some very profound minds, penetrated with religion, such as Leibnitz, have been inclined to believe in it. I am ready to accept it as soon as it can be scientifically shown to exist, and something has been determined as to its nature. Of this I am pretty sure, that, if there be such an endowment, it must be a very complicated one, implying a correlation of properties.

I am inclined to believe that all the phenomena referred to in this article - such as development, production of lifehave appeared according to law, in the loose sense of the term; that is, according to an order of some kind. I hold this in analogy with the whole method of Divine procedure in nature. It is very probable that, in many of the operations, there may have been secondary agencies acting as physical causes. But these secondary agencies are, at the present stage of science, unknown even the agencies which produce development and heredity are very much unknown. In arguing, in these Lectures, for prevailing final cause, my appeal is not to the unknown, but the known, the traces of adaptation in every part of nature; and I cannot allow those who oppose me to appeal to the unknown, when the known is all in my favor. Science may be able to fill up some of the gaps; but when it has done so, I am sure, according to the whole analogy of nature, that, in the process, we will be able to discover final cause, or an adaptation of means to accomplish an end.

Art. II. DARWIN'S DESCENT OF MAN.

WHEN Mr. Darwin published his "Origin of Species," he at once gained as adherents to his theory a large number of young naturalists. His extensive and accurate acquaintance with all departments of Natural History, the pains taken by him in the collection of facts, and the simple and ingenious way in which he stated them, prepared men to listen to him; and, as they did so, they found he was able by Natural Selection to account for a number of phenomena which could not otherwise be explained. But of late there has appeared a disposition, even among those who were at first taken with the theory, carefully to review it. All candid minds admit that it explains much, that it explains modifications which plants and animals undergo from age to age; but many doubt whether it accounts for every thing, whether indeed there is not a profounder set of facts which it does not reach.

Mr. Darwin is candid enough to admit that he cannot account for every thing connected with the appearance of vegetable and animal life. In his fifth edition (1869), he speaks "of life, with its several powers, having been originally breathed by the Creator into a few forms or into one." We have seen (supra, p. 80) that he allows: "How a nerve comes to be sensitive to light hardly concerns us more than how life itself first originated.” But if Natural Selection cannot explain the origin of life, the origin of nerve-force or sensation, it is clear that there is a power above and beyond it, which operated when life appeared, and when sensation appeared, and which may have operated on other occasions in producing higher and ever higher forms of living beings.

It has been known, since at least the time of Aristotle, that there is a striking analogy between man and the lower animals, between all the tribes of animals, and between animals and plants; and Mr. Darwin has, by an accumulation of facts, first in the "Origin of Species," and now in the "Descent of Man," illustrated this point more fully than was ever done before. But it does not therefore follow that the animal is evolved from the

DARWIN'S DESCENT OF MAN.

347

plant, and man from the lower animals. The paintings of Titian have all a certain character, which shows that they are the products of the same great artist. So the correspondences in nature, inanimate and animate, show that the whole proceeds from one grand Designing Mind. We know how the great painter accomplished his aim, by brush and colors and canvas. We see some of the means by which God effects his infinitely grander ends. We see that one of these is the beneficent law of Natural Selection, whereby the weak, after enjoying their brief existence, expire without leaving seed, whereas the strong survive and leave a strong progeny. But the latest science cannot tell how Life arises, or Sensation, or Consciousness, or Intelligence, or Moral Discernment. Even with Mr. Darwin's accumulation of facts bearing on the modification of species, we are made to feel that there are residual phenomena left, which his theory does not explain, and which he does not profess or affect to explain, — in the appearance, for example, of the first plant or the first sentient creature. In the edition of the "Origin of Species" issued in 1869, though he still stands up for Natural Selection as the most important means of producing modification, he allows that it is not the only one. And in his "Animals and Plants under Domestication" (vol. ii. p. 403), he calls in a new theory, that of Pangenesis, according to which every living creature possesses innumerable minute atoms named "gemmules," which are generated in every part of the body, are constantly moving, and have the power of reproduction, and in particular are collected in the generative organs, coming thither from every part of the body. "These almost infinitely numerous and minute gemmules must be included in each bud, ovule, spermatozoon, and pollen grain" (p. 366). It has been generally felt, even by those inclined to follow Mr. Darwin, that this hypothesis is exceedingly vague and confused and complicated. It has certainly no direct evidence in its favor, as these gemmules have never come under the eye of science. The circumstance that Mr. Darwin has been obliged to resort to such hypothesis is a proof that he feels that there is a residuum which his favorite principle of Natural Selection cannot reach.

Whence, then, this element, which we ever come to when we

go far enough back, when we dig sufficiently far down? The older naturalists called it the "vital principle,” not thereby meaning to explain it, but to show merely that they had come to an ultimate fact, for which they had to provide a name. Our younger naturalists do not know well what to make of it. Some of the more superficial of them would deny its existence, and explain all by molecular motion. But the profounder investigators feel that they are ever coming to it, and call it by the name of Pangenesis, or (with Herbert Spencer) "physiological units,” each with an innate power to build up and reproduce the organism. I do believe that this vital power, whatever it be, has its laws; and science is engaged in its proper work when it is seeking to discover them, and may sooner or later be rewarded with success. And of this we may be assured, that when the discovery is made the wonder of intelligent minds will not be diminished.

Whence this element is still the question? It is at least possible and conceivable that it may have been introduced by an immediate fiat of the Great First Cause, continuing to act as a cause, and producing, as the æons roll on, new germs ready to rise to living beings, or living beings ready to bring forth germs; and we may be sure that what God thus places in our world will fit into all that has gone before, and become intertwined with it, and act in unison with it. But it is quite as possible that all this may be effected by some secondary agency, at present unknown, and which may or may not become known. The whole analogy of the Divine procedure, and the beautiful correspondence between the old and the new, seem to point to some common causation producing the first life and all succeeding life. This agency, which like development is only a mode of the Divine agency, may have produced the first life, the first species, every subsequent species, all according to a Divine plan. It is not the development theory: it goes farther back, and shows that behind the development there is a power which produced the life developed, and is involved in the development, the powers working in which, naturalists do not profess to be able to explain.

The development theory is largely an appeal to the unknown.

DARWIN'S DESCENT OF MAN.

349

No one supposes that evolution is an evolution from nothing. It is a law of intuitive intelligence, confirmed by all experience, that every production has a cause, and that there must be power in the agents acting as the cause to produce the effect. That which is evolved always implies a potency in that in which it is involved. A plant or animal with the power of development is always a product of previous causes, and is a cause of coming effects. But no one professes to be able to specify what are the powers involved in development. These powers, if we could discover and separate them, might be found, at least one or more of them, to be intimately connected with, and indeed to proceed from, the power, whatever it is, which originates life, to be a prolongation in fact of that life; the prolongation being implied in the evolution, so that, if there were not a continuance and a transmission of it, there would be no development. There is certainly an element somewhere which gives constant notice of its existence, but has hitherto afforded little insight into its nature, or the laws which it obeys.

It is doubted whether the law of Natural Selection, as unfolded by Darwin, can explain the modifications of plants and animals. Mr. St. George Mivart, in his work on the "Genesis of Species," has endeavored to show: (1) that Natural Selection is incompetent to account for the incipient stages of useful structures; (2) that it does not harmonize with the co-existence of closely similar structures of diverse origin; (3) that there are grounds for thinking that specific differences may be developed suddenly instead of gradually; (4) that the opinion that species have definite though very different limits to their variability is still tenable; (5) that certain fossil transitional forms are absent, which might have been expected to be present; (6) that some facts of geographical distribution supplement other difficulties; (7) that the objection drawn from the physiological difference between species and races still exists unrefuted; (8) that there are many remarkable phenomena in organic forms upon which Natural Selection throws no light whatever, but the explanations of which, if they could be obtained, might throw light upon specific origination. I am far from saying that some of these formidable objections, supported as they are by an array of facts