Modification of Germinal Constitution of Organisms 149 



if we leave the question of dominance out of account, that the foster 

 influence of the white hen was stronger than that of the black hen. If, 

 on the other hand, we consider the foster influence equal in both cases, 

 then we can explain the results as due to the dominance of the white 

 in the male or ovary. 



Guthrie's contention is that the ovaries were wholly 

 removed, and did not regenerate; that the ingrafted ovaries 

 developed, functioned, and were influenced by the foster 

 soma to produce changes in gametic constitution. The 

 doubtful points are concerning the nature of the stock 

 and its gametic make-up, which was not tested in adequate 

 manner, and the gametic constitution of all fowls is known to 

 be very complex (cf. Bateson, Saunders, Davenport, and 

 others) ; and the possibility of regenerated ovaries. Daven- 

 port has repeated the experiments on other but well-known 

 stocks, and summarizes his findings as follows: 



To test these experiments [Guthrie's] I transplanted ovaries from a 

 cinnamon-colored, heavy-boot, pea-combed, low-nostriled hen which 

 breeds true to a white, non-boot, V-combed, five-toed, high-nostriled 

 hen, and mated her with a cock whose characters resembled those of 

 the hen from which the eggs had been borrowed. Had the engrafted 

 ovary been functional, the chicks must have all been like the cock. 

 ActuaUy, they were exactly what expectation calls for when such a 

 cock is mated to such a hen like the so-called foster mother. The 

 engrafted eggs are not functional ; the ovary had degenerated. 



SLx experiments of this sort were made altogether and in no case 

 was there evidence of a functional graft; far less of an influence on the 

 eggs of the foster mother's soma. 



These experiments, made on better-known stock, with 

 many sources of error constantly in mind, give exactly con- 

 tradictory results. Ecjually convincing and identical in 

 result are the in\-estigations of Castle in guinea-pigs, where 

 no effect of the foster soma upon the ingrafted ovar}' was 



