212 Heredity and Eugenics 



of tlie i^rocess at the bottom of the observed changes. In 

 both, tliere are changes following altered conditions, and 

 there ha\'e resulted changes in the organism which are 

 known to occur in many instances, only in these experi- 

 ments s<ime effort was made to test the permanency of 

 the \'ariation and its behavior in subsec^uent crosses. In 

 both, the change seems to be a germinal one, as is indicated 

 b}- its behavior in inheritance. Whether the change is a di- 

 rect germinal or an indirect one, due to somatic inffuence or 

 transmission, the experiments cannot decide. 



Precisely similar are Sumner's experiments in sub- 

 jecting mice to high and low temperatures, where at the 

 end differences were found which were attributed to the 

 effect of the difl'erent conditions. Differences there were 

 at the end, but in mammals so variable as mice carefully 

 pedigreed strains free from biot\i:)es should have been used, 

 and adecjuate parallel controls should have been main- 

 tained. In that controls of critical character were lack- 

 ing and the possibility of biotypes was not eliminated from 

 the stock used, the results obtained are easily attributed to 

 gradual selection of biotji^es or of actuation of latent 

 characters, as well as to the effect of changed temperatures. 

 As for the Cjuestion of somatic inffuence or direct germinal 

 effect, the exi)eriments are not conducted so as to give proper 

 evidence thereon and are capable of any interpretation. 

 The experiments show, however, that changed conditions 

 changed the stock, which change may \\&\q resulted from 

 an_\' of the methods suggested, and tire change is ai)par- 

 entl}' permanent although the series was too short to answer 

 this fiuestion adecjuately. 



In insects, I have obtained modifications in various 

 wa}s, some of wliich will be described in a later portion 



