continuous absence of certain gemmules through so many centuries and so many generations. Yet it is not at all so, and this fact seems to amount almost to an experimental demonstration that the hypothesis of pangenesis is an insufficient explanation of individual evolution.

3

Two exceedingly good criticisms of Mr. Darwin's hypothesis have appeared. One of these is by Mr. G. H. Lewes,1 the other by Professor Delpino of Florence.2 The latter gentleman gives a report of an observation made by him upon a certain plant, which observation adds force to what has just been said about the Jewish race. He says: "If we examine and compare the numerous species of the genus Salvia, commencing with Salvia officinalis, which may pass as the main state of the genus, and concluding with Salvia verticillata, which may be taken as the most highly developed form, and as the most distant from the type, we observe a singular phenomenon. The lower cell of each of the two fertile anthers, which is much reduced and different from the superior even in Salvia officinalis, is transmuted in other salvia into an organ (nectarotheca) having a very different form and function, and finally disappears entirely in Salvia verticillata.”

"Now, on one occasion, in a flower belonging to an individual of Salvia verticillata, and only on the left stamen, I observed a perfectly developed and pollinigerous lower cell, perfectly homologous with that which is normally developed in Salvia officinalis. This case of atavism is

1 See Fortnightly Review, New Series, vol. iii. April 1868, p. 352.

2 This appeared in the Rivista Contemporanea Nazionale Italiana, and was translated and given to the English public in Scientific Opinion of September 29, October 6, and October 13, 1869, pp. 365, 391, and 407. See Scientific Opinion of October 13, 1869, p. 407.

truly singular. According to the theory of Pangenesis, it is necessary to assume that all the gemmules of this anomalous formation, and therefore the mother-gemmule of the cell, and the daughter-gemmules of the special epidermic tissue, and of the very singular subjacent tissue of the endothecium, have been perpetuated, and transmitted from parent to offspring in a dormant state, and through a number of generations, such as startles the imagination, and leads it to refuse its consent to the theory of Pangenesis, however seductive it may be." This seems a further confirmation of what has been advanced as to the Jews.

The main objection raised against Mr. Darwin's hypothesis is that it (Pangenesis) requires so many subordinate hypotheses for its support, and that some of these are not tenable.

1

Professor Delpino considers that as many as eight of these subordinate hypotheses are required, namely, that— "1. The emission of the gemmules takes place, or may take place, in all states of the cell."

"2. The quantity of gemmules emitted from every cell is very great."

"3. The minuteness of the gemmules is extreme.”

"4. The gemmules possess two sorts of affinity, one of which might be called propagative, and the other germinative affinity.

"5. By means of the propagative affinity all the gemmules emitted by all the cells of the individual flow together and become condensed in the cells which compose the sexual organs, whether male or female (embryonal vesicle, cells of the embryo, pollen grains, fovilla, antherozoids, spermatozoids), and likewise flow together and be1 See Scientific Opinion of September 29, 1869, p. 366.

come condensed in the cells which constitute the organs of a sexual or agamic reproduction (buds, spores, bulbilli, portions of the body separated by scission, &c.)."

"6. By means of the germinative affinity, every gemmule (except in cases of anomalies or monstrosities) can be developed only in cells homologous with the mother-cells of the cell from which they originated. In other words, the gemmules from any cell can only be developed in unison with the cell preceding it in due order of succession, and whilst in a nascent state.”

“7. Of each kind of gemmule a great number perishes; a great number remains in a dormant state through many generations in the bodies of descendants; the remainder germinate and reproduce the mother-cell."

"8. Every gemmule may multiply itself by a process of scission into any number of equivalent gemmules."

Mr. Darwin has published a short notice in reply to Professor Delpino, in Scientific Opinion of October 20, 1869, p. 426. In this reply he admits the justice of Professor Delpino's attack, but objects to the alleged necessity of the first subordinate hypothesis, namely, "that the emission of gemmules takes place in all states of the cell." But if this is not the case, then a great part of the utility and distinction of Pangenesis is destroyed, or, as Mr. Lewes justly says: "If gemmules produce whole cells, we have the very power which was pronounced mysterious in larger organisms."

Mr. Darwin also does not see the force of the objection to the power of self-division which must be asserted of the gemmules themselves if Pangenesis be true. The objection, however, appears to many to be a serious one.

1 Fortnightly Review, New Series, vol. iii. April 1868, p. 508.

To admit the power of spontaneous division and multiplication in such rudimentary structures seems a complete contradiction. The gemmules, by the hypothesis of Pangenesis, are the ultimate organized components of the body, the absolute organic atoms of which each body is composed; how then can they be divisible? Any part of a gemmule would be an impossible (because a less than possible) quantity. If it is divisible into still smaller organic wholes, as a germ-cell is, it must be made up as the germ-cell is, of subordinate component atoms, which are then the true gemmules. This process may be repeated ad infinitum, unless we get to true organic atoms, the true gemmules, whatever they may be, and they necessarily will be incapable of any process of spontaneous fission. It is remarkable that Mr. Darwin brings forward in support of gemmule fission the observation that "Thuret has seen the zoospore of an alga divide itself, and both halves germinate." Yet on the hypothesis of Pangenesis, the zoospore of an alga must contain gemmules from all the cells of the parent algæ, and from all the parts of all their less remote ancestors in all their stages of existence. What wonder, then, that such an excessively complex body should divide and multiply; and what parity is there between such a body and a gemmule? A steam-engine and a steelfiling might equally well be compared together.

Professor Delpino makes a further objection, which, however, will only be of weight in the eyes of Vitalists. He says, Pangenesis is not to be received because "it leads directly to the negation of a specific vital principle, coordinating and regulating all the movements, acts, and functions of the individuals in which it is incarnated. For 1 Scientific Opinion of October 13, 1869, p. 408.

Pangenesis of the individual is a term without meaning. If, in contemplating an animal of high organization, we regard it purely as an aggregation of developed gemmules, although these gemmules have been evolved successively one after the other, and one within the other, notwithstanding they elude the conception of the real and true individual, these problematical and invisible gemmules must be regarded as so many individuals. Now, that real, true, living individuals exist in nature, is a truth which is persistently attested to us by our consciousness. But how, then, can we explain that a great quantity of dissimilar elements, like the atoms of matter, can unite to form those perfect unities which we call individuals, if we do not suppose the existence of a specific principle, proper to the individual but foreign to the component atoms, which aggregates these said atoms, groups them into molecules, and then moulds the molecules into cells, the cells into tissues, the tissues into organs, and the organs into apparatus?"

'But, it may be urged in opposition by the Pangenesists, your vital principle is an unknown and irresolute x. This is true; but, on the other hand, let us see whether Pangenesis produces a clearer formula, and one free from unknown elements. The existence of the gemmules is a first unknown element; the propagative affinity of the gemmules is a second; their germinative affinity is a third; their multiplication by fission is a fourth-and what an unknown element!"

"Thus, in Pangenesis, everything proceeds by force of unknown elements, and we may ask whether it is more logical to prefer a system which assumes a multitude of unknown elements to a system which assumes only a single one?"