Ill 



97 



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 Agamo- 

 genetic processes, on the other hand, end in a com- 

 plete 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 Kolliker 

 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 ap- 

 pear to exist in the series of known forms. 



Strongly and freely as we have ventured to 

 disagree with Professor Kolliker, 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 



