1892.] Phenomena and Development of Fecundation. 297 



will likely need illustration to make it plain. Suppose we 

 imagine an organism in which sex has just arisen and wo thus 

 have fertilization for the first time. In the egg cell resulting 

 from this fertilization we would have mingled the germ plasms 

 of but two parents, or but two kinds of chromatin in the 

 nucleus; the chromatin, be it remembered, being the organ to 

 which all such phenomena are traced. This daughter organ- 

 ism now conjugates with another similar individual which is 

 also but one generation removed from the sexual origin. In 

 the organism resulting from this union we obviously have 

 commingled in the chromatin elements four ancestral tenden- 

 cies or idioplasms. It is unnecessary to carry this further, 

 obviously the next generation form a similar union, would 

 contain 8 ancestral idioplasms, the next 16, the 10th genera- 

 tion 1024, and so on, doubling each time with every sexually 

 produced generation. It is merely following the well known 

 calculation made by breeders who merely differ in that they 

 use the term blood, half blood or quarter blood, instead of 

 germ, plasm or idioplasms as we have. 



While in each succeeding generation the number of germ 

 plasms are doubled, their quantities are reduced by one-half. 

 Thus in a series of generations the continually recurring 

 divisions of the ancestral germ plasms must theoretically 

 ultimately reach a limit. So Weismann argues that the reduc- 

 tion in the number of chromatin bands accomplished by the 

 formation of the second polar globule is to reduce by one-half 

 the number of the ancestral germ plasms in the ovum, and the 

 ancestral germ plasm added by the spormato/.oan brings the 

 number of germ plasms in the ovum up to the normal num- 

 ber which he supposes to be present, This theory is of course 

 based on the almost universally accepted theory that fertiliza- 

 tion consists in that an equal number of chromatin loops from 

 either parent are placed side by side and form the new seg- 

 mentation nucleus. 



Character of Sperm.— The character of the spermatozoon is 

 familiar to all. It consists of a minute head, composed chiefly 

 of chromatin nuclear matter with a minimum allowance of 

 cytoplasm and a long contractile tail which working behind 



