RECAPITULATION 237 



when killed had a single embryo in one uterus and no 

 trace of the original ovaries in the normal position. 

 But Foa was not investigating the influence of 

 somatic characters on ova in the grafted ovaries, and 

 does not even mention the characters or breed of the 

 rabbits he used or of the young which were produced 

 from the grafted ovaries. Castle x carried out 

 seventy-four transplantations of ovaries principally 

 in guinea-pigs. Out of all these only one grafted 

 female produced young. In this case the ovaries 

 of two different black guinea-pigs about one month 

 old were grafted into an albino female about five 

 months old. After recovery the grafted female 

 was kept with an albino male. She produced six 

 young in three pregnancies, first two, then one, and 

 lastly died with three foetus in the uteri. All these 

 were black, with some red hairs among the black. 

 One of the first two young had a white forefoot. In 

 this case black is dominant, and therefore there is 

 nothing extraordinary in the offspring from a black 

 grafted ovary being black. The presence of red 

 hairs and a white foot is no evidence of the influence 

 of the foster soma, but is due to imperfect domin- 

 ance. When the same male was mated with a normal 

 black female the offspring were black with red 

 hairs interspersed. 



All these experiments are open to the following 

 criticism. It has been the main argument of this 

 volume that there are two distinct kinds of characters 

 in all organisms namely, those of somatogenic 

 origin and those of gametogenic origin. Theory 

 supposes that somatic modifications by means of 



1 W. E. Castle and J. C. Phillips, On Germinal Transplantation in 

 Vertebrates, Pub. Carnegie Institution in Washington (1911), No. 144. 



