GERM CELLS AND SOMATIC CELLS 



LEO LOEB 



Results obtained in the field of experimental pathology 

 and especially in cancer research have an important bear- 

 ing on certain problems of general biology. In the follow- 

 ing I wish to consider connectedly some of these facts 

 from this point of view. 



I. A sharp distinction between germ cells and somatic 

 cells has become clearly established, especially through 

 the writings of Xussbaum and WVismann. More recent 

 results which demonstrated that the differentiation of 

 germ cells from the somatic cells at a very early stage 

 of embryonic development and their non-participation in 

 the formation of somatic tissues exists in various species, 

 tended to emphasize this sharp distinction between 

 somatic and germ cells. 



Weismann 2 especially insisted on the radical difference 

 between germ cells and somatic cells, inasmuch as he 

 attributed potential immortality to the former and only a 

 temporary existence to the latter. And Weismann re- 

 gards this difference as essentially founded in the struc- 

 ture of both kinds of cells and fundamentally connected 

 with the functioning of the somatic cells; this difference 

 was obtained through selective processes as an adaptation 

 in the struggle for existence. He does not regard the 

 death of somatic cells as an accidental occurrence due to 

 unfavorable conditions which it might be in our power to 

 change, but as an inherent characteristic of somatic cells. 

 He mentions, though casually, that the life of the cock's 

 comb might be prolonged l>\ gra fling it on another fowl — 



