34 BIOLOGICAL LECTURES. 



greater than anything human, if not god-like. The complete 

 parallelism of the "reducing division" in the sperm and egg 

 has never been established. The comparison of these processes 

 in the two is still only approximate, because in the truly holo- 

 blastic Q.gg there is, in some cases, an apparent temporary sub- 

 stitution of the male nucleus for the female, as is shown by the 

 former's assuming a position of equilibrium at the center of 

 the ovum (Ascaris), a condition of things that does not and 

 could not occur in the sperm cell. 



A still more important contrast is the almost incredible dif- 

 ference of volume of the two kinds of sex-cells of the same 

 species. In man, the ratio of volume of the male cell to the 

 female is as i to 3,000 approximately. This extreme contrast 

 of volume is associated with corresponding contrasts in their 

 properties. There can hardly be any doubt that the mature 

 male cell is in a nearly potential or static state of metabolic 

 transformation of its substance, and is characterized by an 

 almost complete want of stored metabolizable reserve material. 

 The egg is in a similar static state, but, on the other hand, 

 contrasts with the male element in that the development of a 

 more or less voluminous mass of reserve material within it 

 has seemingly been also associated with its loss, as a rule, of 

 the power to begin an independent development. The power 

 of the male cell to begin its transformation and growth through 

 metabolism appears to be arrested until it finds the material 

 in which its mere presence will set up transformations. This 

 it must do by in some way setting free and diffusing some of 

 its own molecules osmotically and mechanically through the 

 egg. The substance of the egg appears therefore to be com- 

 plementary to that of the spermatozoon. The power to set up 

 transformations within the egg leading to the development of 

 a new being is not manifested aside from the presence of the 

 male element except in cases of parthenogenesis. Even the 

 expulsion of the polar cells is not initiated until the stimulus 

 of the presence of the male element is experienced by the egg. 



Another contrast is found in the times of the advent of the 

 " reducing division " in the two kinds of sex-cells. In the male 

 cell the "reducing division" occurs earliest, or while it is 



