The Intimate Causes of Old Age. 217 



The species, indeed, as conceived of in the Weissmann 

 hypothesis, was merely an abstraction ; the individual 

 after all was the desideratum ; — but little points like 

 this sometimes escape the minds of great philosophers. 



It must be confessed, too, that something equally 

 nebulous attaches to the Weissmann theorem of the Germ- 

 plasm and Heredity. 



The Germ-plasm of Weissmann is the human repro- 

 ductive tissue, a cell colony which lives on, deathless, 

 from generation to generation ; the soma alone dies ; the 

 germ-plasm has survived from the time unicellular life 

 was the only form of life on the earth. Rejecting 

 the theory of Darwin and others, that gemmules from 

 every cell of the organic tissues are garnered in the re- 

 productive tissue, to be extruded as embryonic cells, 

 Weissmann taught that the reproductive cells, by permu- 

 tations and combinations of the germinal substance, are 

 equal to the task of originating new generations of man- 

 kind, unaided, and that the soma has nothing to do with 

 reproduction save the servile task of bearing the germ- 

 plasm forward in the world and supplying it with food. 



Here, again, common sense could not help thinking that 

 as between these rival theories of reproduction, the truth 

 may lie midway ; that the despised soma while not trans- 

 ferring organized "gemmules" to the reproductive cell 

 colony, may yet by virtue of "nervous currents," which 

 pass to and fro, so influence, mold, and individualize the 



