ACQUIRED CHARACTERS 85 



forth by a known external cause; second, it must be 

 something new or different from what was already 

 exhibited before, and not be simply the reawakening 

 of a latent germinal character; and third, the same 

 particular character must reappear in succeeding 

 generations in the absence of the original external 

 cause which brought forth the character in question. 

 As yet these conditions have not been convincingly 

 met in the evidence which has been brought forward 

 in support of the inheritance of acquired characters. 



11. THE COMPARATIVE INDEPENDENCE OF GERM 

 AND SOMA 



The fact that the germ is only a pilgrim stranger 

 passing through the homeless land of the soma is well 

 brought out by the critical ovarian transplantation 

 experiments of Castle and Phillips upon guinea-pigs. 



The ovaries of an albino guinea-pig were removed 

 and those of a black guinea-pig were grafted in their 

 place. After recovery from the operation the animal 

 was mated with an albino male three times before 

 pneumonia unfortunately put an end to this famous 

 experiment. The resulting offspring were all black, 

 as shown in Figure 12. Ordinarily when albinos are 

 crossed they produce only albinos. It is obvious that 

 the pneumonia victim was not the mother of the six 

 black offspring although she bore them. "The conclu- 

 sion is forced upon us," to quote Babcock and Clausen's 

 comments on the case, "that the egg-cell during its 

 growth does not change in germinal constitution. Its 

 growth is like the growth of a parasite or of a wholly 



