Kansas Academy of Science. 



THE GERM-PLASM HYPOTHESIS OF WEISMANN 

 UNTENABLE. 



By L. C. WoosTER. Department of Biology and Geology, State Normal School, Emporia. 



MANY scientists who have approached biology from the side of 

 mathematics, physics aad chemistry have injected the certain- 

 ties of physical science into their explanation of the phenomena of 

 life, a variable. In the foremostrank of philosophical biologistsstands 

 August Weismann, who is author of the most ingenious materialistic 

 hypothesis offered to explain heredity and ontogeny. Weismann 

 claims in his hypothesis that a very precious portion of germ-plasm, 

 peculiar in its qualities to each species, is handed on from genera- 

 tion to generation, bearing impressed on the matter composing it 

 the characteristics of parents to offspring. Shielded from rude 

 contact with the external world, the qualities of the plasm change 

 but slowly, just enough to carry forward the work of evolution. 



Filled with admiration for the great atomic theory, in which the 

 qualities of the molecule are said to depend upon the kind, number 

 and arrangement of the atoms composing it, Weismann imagined 

 that the germ-plasm must consist of myriads of tiny aggregations 

 of molecules, which he decided to name biophors, or bearers of the 

 qualities of life. These biophors must equal in number of kinds 

 the total number of qualities exhibited by all plants and animals, 

 one biophor for each quality. As there are many millions of such 

 qualities, the disciples of Weismann match them with billions of 

 biophors in each germ-cell. 



Each biophor, Weismann imagined, could assimilate food, grow 

 and divide so the total number would equal all the needs of all the 

 cells of each individual. Weismann further imagined that the bio- 

 phors became united into groups which he named determinants, 

 there being one determinant for each cell of the body, except the 

 germ-cells. The germ-cells must have all the different kinds of 

 determinants needed by the developing plant or animal. But these 

 determinants of the germ-cells could also absorb food, grow and 

 divide as well as the biophors, so there would always be enough of 

 them for all the cells of the body, no matter how many they might 

 be. The determinants were thought to be somewhat piggish in 

 their dispositions so they would struggle with one another for food 

 and oxygen, and some would get more than their due share and 

 grow faster and become dominant, while others would starve and 



