But if this be a true statement of the nature of the process of Agamogenesis, how can it enable us to comprehend the production of new species from already existing ones?  Let us suppose Hyaenas to have preceded Dogs, and to have produced the latter in this way.  Then the Hyaena will represent A, and the Dog, B. The first difficulty that presents itself is that the Hyaena must be asexual, or the process will be wholly without analogy in the world of Agamogenesis.  But passing over this difficulty, and supposing a male and female Dog to be produced at the same time from the Hyaena stock, the progeny of the pair, if the analogy of the simpler kinds of Agamogenesis[67] is to be followed, should be a litter, not of puppies, but of young Hyaenas.  For the Agamogenetic series is always, as we have seen, A:  B:  A:  B, &c.; whereas, for the production of a new species, the series must be A:  B:  B:  B, &c.  The production of new species, or genera, is the extreme permanent divergence from the primitive stock.  All known Agamogenetic processes, on the other hand, end in a complete return to the primitive stock.  How then is the production of new species to be rendered intelligible by the analogy of Agamogenesis?

The other alternative put by Professor Koelliker—­the passage of fecundated ova in the course of their development into higher forms—­would, if it occurred, be merely an extreme case of variation in the Darwinian sense, greater in degree than, but perfectly similar in kind to, that which occurred when the well-known Ancon Ram was developed from an ordinary Ewe’s ovum.  Indeed we have always thought that Mr. Darwin has unnecessarily hampered himself by adhering so strictly to his favourite “Natura non facit saltum.”  We greatly suspect that she does make considerable jumps in the way of variation now and then, and that these saltations give rise to some of the gaps which appear to exist in the series of known forms.

Strongly and freely as we have ventured to disagree with Professor Koelliker, we have always done so with regret, and we trust without violating that respect which is due, not only to his scientific eminence and to the careful study which he has devoted to the subject, but to the perfect fairness of his argumentation, and the generous appreciation of the worth of Mr. Darwin’s labours which he always displays.  It would be satisfactory to be able to say as much for M. Flourens.

But the Perpetual Secretary of the French Academy of Sciences deals with Mr. Darwin as the first Napoleon would have treated an “ideologue;” and while displaying a painful weakness of logic and shallowness of information, assumes a tone of authority, which always touches upon the ludicrous, and sometimes passes the limits of good breeding.

For example (p. 56):—­

“M.  Darwin continue:  ’Aucune distinction absolue n’a ete et ne peut etre etablie entre les especes et les varietes.’  Je vous ai deja dit que vous vous trompiez; une distinction absolue separe les varietes d’avec les especes.”

“Je vous ai deja dit; moi, M. le Secretaire perpetuel de l’Academie des Sciences:  et vous