170 MODES OF RESEARCH IN GENETICS 



the young man starting out to-day to be a breeder 

 of fine cattle, of fine horses, of fine chickens, is 

 likely to attain his goal somewhat sooner if he 

 thoroughly understands the meaning of those laws 

 of inheritance associated with the name of Mendel. 



The most important general principles which 

 the scientific study of genetics has firmly grounded 

 are, it seems to me, these : 



(a) That the fundamental basis of all inheritance 

 is to be found in the germinal constitution of the 

 individual rather than in the body or soma. Those 

 qualities alone are inherited, which are innate in 

 the germ cells, the ova and the spermatozoa. Here 

 only can the breeder find the means with which to 

 accomplish his ends. However interesting theoret- 

 ically may be those rare and still doubtful cases 

 in which extraordinary influences acting upon the 

 body under the controlled and special conditions 

 of the laboratory may perhaps influence the germ 

 cells through the soma, they have no bearing on 

 the practical conduct of the breeders' craft. Ge- 

 netics has demonstrated that he may cast aside, 

 for once and all, that mass of tradition and super- 

 stition which assumed that influences specifically 

 affecting the body will specifically modify subse- 

 quent generations. Has not genetics done breed- 

 ing a service of great value in freeing it of the 

 sinister influence of "telegony," "saturation," 

 "maternal impressions " and similar sorts of non- 

 sense ? 



