12 CALIFORNIA Af'ADElIY OF SCtENCES. 



tion i8 the key to his whole position. He has been at 

 considerable pains to controvert the view that somato- 

 plasm may be converted into germ-plasm; but in mak- 

 ing the attack he has overlooked the necessity for de- 

 fense." Prof. Vines then gives quotations from Prof. 

 Weismann illustrative of his theory of heredity, and of 

 his assertion that germ-plasm must be a substance of 

 great stability in order to be able to transmit all of the 

 complex modifications which it acquires. He then con- 

 tinues his objections as follows: A part of the germ- 

 plasm, Weismann claims, goes to the formation of the 

 somatoplasm of the developing embryo, while what re- 

 mains goes to the formation of the nucleus of the germ- 

 cells of the embryo. But the germ-plasm of the ovum. 

 Prof. Vines claims, cannot influence the somatoplasm of 

 the embryo, even from Prof. Weismann's standpoint. 

 "This function cannot be discharged," he says, " by 

 that portion of the germ-plasm of the ovum which has 

 become converted into the somatoplasm of the embryo, 

 for the simple reason that it has ceased to be germ-plasm 

 and must therefore have lost the properties characteris- 

 tic of that substance. Neither can it be discharged by 

 that portion of the germ-plasm of the ovum which is 

 aggregated in the germ-cells of the embryo, for under 

 these circumstances it is withdrawn from all direct rela- 

 tion with the developing somatic cells. The question 

 remains without an answer." So much for the criticism 

 from Prof. A\'eismann's own standpoint. From Prof. 

 Vine's position it is open to a still more vital attack. 

 Claiming as he does that the possibility of germ-plasm 

 being converted into somatoplasm is an unwarrantable 

 assumption on the part of Prof. Weismann, Prof. Vines 

 cannot but assert that the entire theory of germ-plasm 

 which is built upon this assumption, lawnt collapse. 

 I'urthermore, inasmuch as the embrvo is not formed 



