318 SEA-SIDE STUDIES. 



indispensable. In granting the indispensable nature of the 

 aid of such extra horses, no one would think of saying that 

 it proved the necessity of four horses to carriage travelling. 



What the precise nature of the influence exercised by the 

 spermatozoon truly is, we know not ; but an hypothesis 

 may be here suggested, provided the reader regard it as an 

 hypothesis, not at all interfering with the positive facts 

 just stated. We may give speculation elbow-room for a 

 moment, and return to our discussion in no worse condition 

 than before. When the spermatozoon penetrates into the 

 interior of the ovum, it there becomes dissolved, and finally 

 disappears. According to Meissner* its metamorphosis is 

 precisely the same, whether occurring inside the ovum or 

 apart from it, and in each case the process is one of gradual 

 change into fat. Now if we consider the absolute import- 

 ance of fat in the formation of cells, and remember that the 

 development of the ovum is through a continuous multi- 

 plication of cells, the influence of the spermatozoon will be 

 perfectly intelligible as that of furnishing increase of cell- 

 production. The sperm-cell being proved identical with 

 the germ-cell, we may compare its additional force to the 

 force added by the extra horses which must draw tlie 

 carriage up the liill.f 



Having given expression to my hypothesis, I return to 

 the survey of the various modes of Reproduction, which we 



* In Siebold's ij KoLLIKEr's Zeitschriftf. Wissen. Zoologie, vi. 



t Wolff, Theorie von der Generation, p. 24S-9, maintains that the sper- 

 matozoon is nothing but the highest form of concentrated nutriment ; in his 

 day it was thought to be the miniature animal, the office of tho mother being 

 .simply to feed and rear it. 



