THE MENDELTAN EATIO AND BLENDED IN- 

 HERITANCE 1 



SHINKISHI HATAI 

 The Wistar Institute of Anatomy 



The indefatigable efforts of neo-Mendelists bave suc- 

 ceeded in bringing numerous cases of inheritance, which 

 had previously been considered incompatible with Men- 

 del's law, into their domain by widening the original 

 limitations. We still have many instances such as 

 blended inheritance which can not apparently be harmon- 

 ized with the law of Mendel. Recent experiments which 

 demonstrate the existence of various degrees of domi- 

 nance as well as the mutability of the determinants in 

 their behavior, suggested to the writer that various 

 forms of inheritance might be considered as degrees of 

 modification of the law of Mendel. With this view in 

 mind, I have attempted to obtain some general expres- 

 sion for the underlying principle of the law of inherit- 

 ance by which means Mender.- original law may possibly 

 be theoretically connected with the other cases. In fact, 

 I was compelled to pursue this investigation in connec- 

 tion with my own experiments on the inheritance of the 

 weight of the central nervous system, though this is not 

 yet ready to present at this time. 



In carrying out this investigation, I have assumed that 

 the germ plasm is composed of many factors, the true 

 nature of which is unknown, but which in one way or 

 another determine the characters in the offspring. It is 

 these hypothetical factors which are here provisionally 

 called determinants. With this understanding, we may 

 now proceed to the argument. 



Suppose a gamete of one parent after the reducing 

 division contains n determinants, the whole group of 



1 Bead before the American Society of Naturalists, December 30, 1910. 

 99 



