Mr. Darwin appears, by "Natural Selection," to destroy the reality of species, and by Pangenesis that of the individual. Mr. Lewes observes of the individual that "This whole is only a subjective conception which summarizes the parts, and that in point of fact it is the parts which are reproduced." But the parts are also, from the same point of view, merely subjective until we come to the absolute organic atoms. These atoms, on the other hand, are utterly invisible, intangible; indeed, in the words of Mr. Darwin, inconceivable. Thus, then, it results from the theories in question, that the organic world is reduced to utter unreality as regards all that can be perceived by the senses or distinctly imagined by the mind; while the only reality consists of the invisible, the insensible, the inconceivable; in other words, nothing is known that really is, and only the non-existent can be known. A somewhat paradoxical outcome of the speculations of those who profess to rely exclusively on the testimony of sense. "Les extrêmes se touchent," and extreme sensationalism shakes hands with the "das Seyn ist das nichts" of Hegel.

Altogether, the hypothesis of Pangenesis seems to be little, if at all, superior to earlier hypotheses of a more or less similar nature.

Apart from the atoms of Democritus, and apart also from the speculations of medieval writers, the molecules of Bonnet and of Buffon almost anticipated the hypothesis of Pangenesis. According to the last-named author,2 organic particles from every part of the body assemble in

1 Fortnightly Review, New Series, vol. iii. April 1868, p. 509.

2 "Histoire Naturelle, générale et particulière," tome ii. 1749, p. 327. "Ces liqueurs séminales sont toutes deux un extrait de toutes les parties du corps," &c.

the sexual secretions, and by their union build up the embryo, each particle taking its due place, and occupying in the offspring a similar position to that which it occupied in the parent. In 1849 Professor Owen, in his treatise on "Parthenogenesis," put forward another idea. According to this, the cells resulting from the subdivision of the germ-cell preserve their developmental force, unless employed in building up definite organic structures. In certain creatures, and in certain parts of other creatures, germ-cells unused are stored up, and by their agency lost limbs and other mutilations are repaired. Similar unused products of the germ-cell are also supposed to become situate in the generative products.

According to Mr. Herbert Spencer, in his "Principles of Biology," each living organism consists of certain so-called "physiological units." Each of these units has an innate power and capacity, by which it tends to build up and reproduce the entire organism of which it forms a part, unless in the meantime its force is exhausted by its contributing to the production of some distinct and definite tissue-a condition somewhat similar to that conceived by Professor Owen.1

Now, at first sight, Mr. Darwin's atomic theory appears to be more simple than any of the others. It has been objected, that while Mr. Spencer's theory requires the assumption of an innate power and tendency in each physiological unit, Mr. Darwin's, on the other hand, re

1 Mr. Spencer, however, holds that so long as the process of growth and multiplication by gemmation goes on actively, so that the aggregates and their units, in a continual state of change, are not held in such constant relation as to bring about an equilibrium between the form of the one and the polarities of the other, the process of growth and multiplication may go on without limit.

quires nothing of the kind, but explains the evolution of each individual by purely mechanical conceptions. In fact, however, it is not so. Each gemmule, according to

Mr. Darwin, is really the seat of powers, elective affinities, and special tendencies as marked and mysterious as those possessed by the physiological unit of Mr. Spencer, with the single exception that the former has no tendency to build up the whole living, complex organism of which it forms a part. Some may think this an important distinction, but such can hardly be the case, for Mr. Darwin considers that his gemmule has the innate power and tendency to increase and transform itself into the whole living, com plex cell of which it forms a part; and the one tendency is, in principle, fully as difficult to understand, fully as mysterious, as the other. The difference is but one of degree, not of kind. Moreover, the one conception in the case of the "physiological unit" explains all, while with regard to the gemmule, as we have seen, its power of growth has to be supplemented by other powers and tendencies, each distinct, and each in itself inexplicable and profoundly mysterious.

That there should be physiological units possessed of the power attributed to them, harmonizes with what has recently been put forward by Dr. H. Charlton Bastian; 1 who maintains that under fit conditions the simplest organisms develop themselves into relatively large and complex ones. This is not supposed by him to be due to any inheritance of ancestral gemmules, but to direct

1 As this sheet of the second edition is passing through the press, a work has appeared written by Dr. H. Charlton Bastian, and entitl "The Modes of Origin of Lowest Organisms." London and New York: Macmillan and Co.

growth and transformation of the most minute and the simplest organisms, which themselves, by all reason and analogy, owe their existence to immediate transformation from the inorganic world.

On the whole, then, we seem justified in asserting that there are grave difficulties in the way of the reception of the hypothesis of Pangenesis, which moreover, if established, would leave the evolution of individual organisms, when thoroughly analysed, little if at all less mysterious or really explicable than it is at present.

As was said at the beginning of this chapter, “Pangenesis" and "Natural Selection" are quite separable and distinct hypotheses. The fall of one of these by no means necessarily includes that of the other. Nevertheless, Mr. Darwin has associated them closely together, and, therefore, the refutation of Pangenesis may render it advisable for those who have hitherto accepted "Natural Selection" to reconsider their acceptance of that theory.

CHAPTER XI.

SPECIFIC GENESIS.

Review of the statements and arguments of the preceding chapters.Cumulative argument against predominant action of "Natural Selection." Whether anything positive as well as negative can be enunciated. Constancy of laws of nature does not necessarily imply constancy of specific evolution.-Possible exceptional stability of existing epoch.-Probability that an internal cause of change exists.—Innate powers must be conceived as existing somewhere or other. -Symbolism of molecular action under vibrating impulses.-Professor Owen's statement.-Statement of the author's view.-It avoids the difficulties which oppose 66 Natural Selection."-It harmonizes apparently conflicting conceptions.-Summary and conclusion.

HAVING now severally reviewed the principal biological facts which bear upon specific manifestation, it remains to sum up the results, and to endeavour to ascertain what, if anything, can be said positively, as well as negatively, on this deeply interesting question.

In the preceding chapters it has been contended, in the first place, that no mere survival of the fittest accidental and minute variations can account for the incipient stages of useful structures, such as, e.g., the heads of flat-fishes, the baleen of whales, limbs of vertebrates, the laryngeal structures of the new-born kangaroo, the pedicellaria of Echinoderms, or for many of the facts of mimicry, and especially