gemmules were supposed to be transported throughout 

 the entire body, and to congregate in the germ-cells, which 

 would be in a sense minute editions of the body which 

 bears them, and would so be capable of producing the same 

 kind of a body. If true, this view would lead to the accept- 

 ance of Lamarck's or even Buffon's doctrine, for changes 

 induced in any organ by other than congenital factors 

 could be impressed upon the germ-cell, and would then be 

 transported together with the original specific characters 

 to future generations. Darwin was indeed a good La- 

 marckian. 



But the researches of post-Darwinians, and especially 

 those of the students of cellular phenomena, have demon- 

 strated that such a view has no real basis in fact. Many 

 naturalists like Naegeli and Wiesner were convinced that 

 there was a specific substance concerned with hereditary 

 qualities as in a larger w r ay protoplasm is the physical basis 

 of life. It remained for Weismann to identify this theo- 

 retical substance with a specific part of the cell, namely, 

 the deeply-staining substance, or chromatin, contained in 

 the nucleus of every cell. Bringing together the accumu- 

 lating observations of the numerous cytologysts of his 

 time, and utilizing them for the development of his some- 

 what speculative theories, Weismann published in 1882 a 

 volume called "The Germ-Plasm," which is an immortal 

 foundation for the later work on inheritance. The essen- 

 tial principles of the germ-plasm theory are somewhat as 

 follows : The chromatin of the nucleus contains the de- 

 terminants of hereditary qualities. In reproduction, the 

 male sex -cell, which is scarcely more than a minute mass of 

 chromatin provided with a thin coat of protoplasm and 

 a motile organ, fuses with the egg, and the nuclei of the 

 two cells unite to form a double body, which contains equal 

 contributions of chromatin from the two parental organ- 

 isms. This gives the physical basis for paternal inheri- 



22 



