SOMK HEMAIUvS ABOUT UMTS IN HEIIEDITY 141 



as chemical consliliitional différences. Phen()ty|)es liowcver may show 

 discontinuous as well as all degrees of continuous variation! 



The genotypical constitution as belonging to every cell penetrates 

 the whole individual with the more or less rare complications, where 

 we may meet »vegetative» segregations or mutations. Hut these pro- 

 cesses have nothing to do with the Weismannian conception of a regular 

 disintegration of the active germplasm during ontogenesis already men- 

 tioned. The same holds good in the several cases in which only cells 

 of the germcyde ( Keiml)ahn ) have the full equipment of chromoso- 

 mes and other granular structures, as for instance in Ascaries (Boverii 

 and some beetles (Hegner). 



The Weismannian form of distinction between Germplasm and 

 »Soma», viz. absolute independence does not exist in reality. The non- 

 inheritance of acquired characters is not a consequence of this assumed 

 independence or difference, but only a striking expression of the fact, 

 that the external conditions may easily mould phenotypes in a more 

 or less adaptive manner, but can hardly or rarely induce changes in the 

 genotype. The Weismannian distinction ^> Keimplasma — Soma which 

 from the point of view of Genetics is totally obsolete has in its purely 

 morphological nature nothing to do with our view^s; his categories are 

 incommensurable with the distinction Genotype — Phenotype. In conclu- 

 ding these somewhat aphoristic remarks I have only to say that my 

 terms »Gcney, »genotypical» and so on have absolutely nothing to do 

 with DE Vries' expression y>Pangenes» (1889) and their assumed be- 

 haviour as units. May I add that the Galtonian antithesis Xatiire- 

 Nurture» is not equivalent to our notions »Genotype-Phenotype> . the 

 phenotype being the reaction of the genotype (»nature ) with the am- 

 bient conditions (»nurture»). 



