38 MODES OF RESEARCH IN GENETICS 



study of such phenomena as regeneration, regula- 

 tion, growth, etc., we have a first-class tool for 

 the analysis of the principles of somatogenesis. 



It is unquestionable that a splendid opportunity 

 lies open for research in genetics by the embryo- 

 logical method, using the term in the broad sense 

 just mentioned. It is altogether usual in current 

 discussions of variation and heredity to neglect 

 completely everything which comes between the 

 two end terms of the ontogenetic series, the germ 

 cell on the one hand and the adult soma on the 

 other hand. But clearly what goes between is a 

 most essential part of heredity itself. It is aston- 

 ishing how little has been done on these extremely 

 obvious problems. Dr. Boring and the writer ' 

 have recently undertaken a study of the regenera- 

 tion of certain organs in heterozygous animals, 

 to see what is the behavior of the successive re- 

 generation in respect of the character for which 

 the individual is heterozygous. Some of the 

 results, as yet unpublished, are very interesting. 

 For example, to mention but a single case, we find 

 that an individual, heterozygous for plumage 

 pattern, may from the same feather follicle at one 

 time produce a feather having a pattern like 

 that of one of the parents, and at another time a 

 feather with a pattern like that characteristic of 



1 Cf . for a preliminary report of some of these experiments, Pearl, 

 R. and Boring, A. M. "Some Physiological Observations regarding 

 Plumage Patterns." Science, N. S., Vol. 39, pp. 143-144, 1914. 



