No. 531] GENOTYPE CONCEPTION OF HEREDITY 155 



"manifestations of life," — is inter alia characterized by 

 the property of auto catalysis. The autocatalysis of 

 living beings must embrace the totality of their geno- 

 typical constituents. It seems to me that this autoca- 

 talysis as well as the compensative and com pie mental 

 maintenance of r/cnoti/picul equilibrium in the organisms, 

 present some of the greatest enigmas of organic life. 



The discussion of etiological problems leads us to the 

 question of pure or impure segregation. In the begin- 

 ning of modern Mendel ian researches several instances of 

 presumed impure segregation of genes in gametogenesis 

 were discussed, e. g., as to color factors in animals. But 

 more thorough analytical experiments have in many such 

 cases demonstrated "purity" in the gametes, the charac- 

 ters in question having proved to be more complicated 

 reactions than at first supposed. Recently Morgan has 

 discussed the question in a quite new manner, suggesting 

 —as a working hypothesis— that the segregation might be 

 not of qualitative but of merely quantitative nature. 

 Hence the gametes should as a rule not be pure. Never- 

 theless, as the author illustrates by means of interesting 

 diagrams, the F 2 -generation of a monohybrid with normal 

 dominance might be composed of two classes of indi- 

 viduals sharply defined. And the author suggests that 

 this idea might be able to explain "the graded series of 

 forms so often met with in experience and so often 

 ignored or roughly classified by Mendelian workers. ' ' 



Here we again touch the question of "blended in- 

 heritance." I suppose that the above-mentioned expla- 

 nations by Lang and East are more consistent with the 

 real nature of the graded series in question. Now the 

 Mendelian work has not only been able to demonstrate 

 that several cases of segregation apparently impure are 

 pure segregations of complicated nature; but even the 

 4 'spotted conditions" as to color in animals and plants, 

 emphasized by Morgan as a puzzling case, does not seem 

 to present any real difficulty for Mendelian explanation. 

 Certainly such cases as ShnU has pointed out, viz., hetero- 



