Modification of Germinal Constitution of Organisms 21.1 



two years. At the end of this period it was found that the 

 head form had changed and that when the modified form 

 was put back into the original conditions the changed form 

 was retained. Unquestionably, in Woltereck's cultures a 

 head form, different from the one with which the culture 

 started, was present at the end of two years, and this did 

 not revert on return to normal conditions; but the failure 

 to carry adequately controlled parallel normal lines does 

 not permit a decision as to whether the change is a real one, 

 or due to the progressive selection of a biotype present 

 but obscured in the original population. Nor do the 

 experiments permit of a decision as to whether the effects 

 observed were due to direct germinal modifications or to so- 

 matic transmission. It is shown that a permanent change 

 of the race resulted, and nothing more. Parallel cultures 

 and much more careful experimentation would be necessary 

 in the effort to answer the more important points. 



Similar in method and in results are the experiments and 

 conclusions obtained by Kammerer on certain amphibians 

 and Lacertilia. For example, Salamandra maculosa is 

 ovaviparous in the lowlands, but its highland variety, 

 S. atra, is viviparous, and the larvae are large when born 

 and have long gills. It was found that lowland forms of 

 S. maculosa kept without water at low temperatures showed 

 reproductive habits and young much like those in S. atra 

 in the alpine regions. In the lizards, temperature was 

 found to be productive of color changes, giving dimorphism 

 in the males of one species and in the females of another. 

 These changes are alternative in crosses. 



In both experiments the results have not been carried 

 far enough to test the inheritance thoroughly, and moreover, 

 the conditions of experiment do not permit of any analysis 



