Art and Science 



plasm " which the new animal itself will in 

 due course issue. 



Contrasting the generally received view 

 with his own, Professor Weismann says that 

 according to the first of these " the organism 

 produces germ-cells afresh again and again, 

 and that it produces them entirely from its 

 own substance." While by the second "the 

 germ-cells are no longer looked upon as the 

 product of the parent's body, at least as far as 

 their essential part the specific germ-plasm 

 is concerned ; they are rather considered as 

 something which is to be placed in contrast 

 with the tout ensemble of the cells which make 

 up the parent's body, and the germ-cells of 

 succeeding generations stand in a similar re- 

 lation to one another as a series of generations 

 of unicellular organisms arising by a continued 

 process of cell-division." * 



On another page he writes : 



" I believe that heredity depends upon the 

 fact that a small portion of the effective sub- 

 stance of the germ, the germ-plasm, remains 

 unchanged during the development of the 



1 "Essays on Heredity/' &c., Oxford, 1889, p. 171. 

 279 



