SEVENTH ANNUAL MEETING 31 



fact a very considerable proportion of the agents effective in 

 stimulating protoplasm may be efficient agents in inciting 

 parthenogenesis in one or another variety of eggs. It has 

 been argued that, if it were possible to find the common factor 

 of all efficient parthenogenetic agents, the cause of the initia- 

 tion of development would be found. This attempt has not, 

 however, led to a satisfactory explanation; and it may be 

 doubted whether such a form of analysis would lead to any 

 more satisfactory results in the case of initiation of develop- 

 ment than in the initiation and propagation of a nerve impulse, 

 which may be equally well started by a similar set of external 

 changes. 



Moreover, while it is obvious that in parthenogenesis, part 

 of mechanism of fertilization must be employed, we need not 

 necessarily gain any direct knowledge of the true fertiliza- 

 tion reaction between ovum and spermatozoon. In fact if we 

 were to accept any theory of parthenogenesis we would still 

 be far from understanding many of the phenomena of fertili- 

 zation associated with initiation of development. 



On any such basis ( 1 ) We do not understand the nature of 

 the immediate reaction between the ovum and spermatozoon 

 in fertilization; (2) We do not understand the nature of the 

 reaction of the sperm nucleus in the interior of the ovum; (3) 

 We do not understand why fertilized ova become non-fer- 

 tilizable; (4) Why immature ova are non-fertilizable ; (5) 

 We do not understand the variations of affinity within a 

 species, leading to almost absolute sterility in self-fertilization 

 in some cases, or between the members of certain varieties in 

 other cases; (6) We do not understand either the sterility or 

 fertility of different species when bred together. 



Not only are these unsolved problems, but we have only the 

 slightest experimental basis for their solution by methods of 

 parthenogenesis. A vague conception that the solution of such 

 problems must lie in the field of chemistry has been entertained, 

 but without any experimental basis whatever until very re- 

 cently, and that of a slight character. 



If these things are true the defect must lie in the methods 

 of investigation because some of the most brilliant students 

 of biology have been concerned with the problems of fertili- 

 zation. The defect in the methods of artificial parthenogenesis 

 is obvious, because it consciously restricts the field of investi- 

 gation. Nothing less than an analysis of the process of fertili- 

 zation itself can give a rounded theory of fertilization. The 

 study of merogeny, of hybrid fertilization, of partial fertiliza- 



