244 SECRETS OF ANIMAL LIFE 



inheritance and some do not. Moreover, the 

 Mendelian doctrine that all characters segregate in 

 inheritance and are uninfluenced by crossing is far 

 from being substantiated by Gates' results. He 

 finds Mendelian splitting, it is true, but much more 

 besides. He finds illustrations of blending and 

 hints of the mutual influence of hereditary char- 

 acters ; he finds curious results called " mutation 

 crosses " and " twin hybrids," which are anything 

 but Mendelian. In short, the Mendelian categories 

 are far too rigid, savoring too much of the in- 

 animate domain. 



The step gained is the demonstration that the 

 bodily peculiarities of mutants are correlated 

 with visible disturbances in the germinal organiza- 

 tion. The next step is to discover all we can in 

 regard to these germinal disturbances. Dr. Gates 

 has described changes in the number, shape, size, 

 arrangement, and structure of the chromosomes; 

 but he is careful to point out that we must push 

 beyond these to chemical or functional changes 

 in particular chromosomes or parts of chromosomes. 

 Furthermore, changes may perhaps occur in the 

 mysterious karyolymph or gel which forms the 

 ground-work of the nucleus. But behind the 

 question of the nature of the germinal changes 

 looms the problem of their origin. The Proteus 

 of the organism has changed into the Proteus of 

 the chromosomes. Do these germinal disturbances 

 come about in response to subtle environmental 

 stimuli penetrating in from without, or does the 



