CONFORMITY TO TYPE 



241 



It goes without saying that so suggestive and com- 

 plete a theory as that of Weismann must take a strong 

 hold and leave a deep impression upon the thoughtful 

 mind. Whatever may be thought of the biophors, 

 determinants, ids, and idants and some, like Adami, 

 believe that they have demolished this elaborate succes- 

 sion by showing the physical impossibility of a sufficient 

 number of them being packed away in the germ plasm 

 the doctrine of the continuity of the germ plasm re- 

 mains unassailed and forms the foundation of much of 

 the thought of the present day. 



During these lengthy excerpts from the writings upon 

 inheritance the reader cannot but have observed that 



Line of succession of 

 individuals. 



> Line of here- 

 ditary trans- 

 mission. 



Flo. 99. Heredity of germ cells and somatic cells. G, Germ cells; S, somatic 

 cells. (Lock.) 



an important difficulty to be overcome, and one upon 

 which considerable time has been spent, is the appearance 

 in the offspring of peculiarities not found in his parents, 

 though present in his earlier forbears. Light upon this 

 obscure subject is found in the thoughtful and important 

 work of Gregor Johann Mendel, an Austrian botanist, 

 who for a number of years studied the phenomena of 

 hybridity among certain peas. His writings, being 

 published in an obscure journal, were overlooked partly 

 for that reason and partly because they appeared in 

 1866 when Darwin was impressing the whole world 

 with his plausible theory of the "Origin of Species by 

 Natural Selection" which so changed scientific thought 

 as to make experiments upon hybridity appear futile. 



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