12 CALIFORNIA ACADEMY OF SCIENCES. 



tion is 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 these circumstances it is withdrawn from all direct rela- 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. Weismann'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, must collapse. 

 Furthermore, inasmuch as the embryo is not formed 



