THE LAMARCKIAN THEORY 421 



taken to indicate that normal conditions favor it, hence a return 

 to the old habits might be only another case of acquisition. 



The Experiments of Guyer and Smith. The experiments of 

 Guyer and Smith are widely cited in this connection. These 

 scientists produced an antiserum of fowl blood by injecting a 

 preparation of the lenses of rabbits' eyes. The antiserum was 

 injected into pregnant rabbits without affecting the eyes of the 

 adult, but the young when born showed several defects. Indi- 

 viduals selected from the defective progeny transmitted eye defect 

 through several generations without further treatment. The pre- 

 caution has been taken to test the transmission of the characters 

 through the male in order that no question of prenatal influence 

 could enter. 



These experiments are the most significant yet reported on the 

 transmission of acquired characters. They have been subjected 

 to severe criticisms by several biologists and have been repeated 

 and confirmed by their authors. Other experimenters have failed 

 to secure similar results, although the significance of their failure 

 is reduced by the fact that they did not follow the same conditions. 

 The present status of the experiments is such that they must be 

 grouped with other evidence as inconclusive, although they are 

 highly suggestive. 



Castle and Phillips' Ovarian Grafts. One of the most striking 

 experiments relating to the inheritance of acquired characters is 

 that performed by Castle and Phillips by transplanting the ovaries 

 of black guinea pigs to white individuals from which the ovaries 

 had been removed. One female in which the operation was 

 successful was later mated with a white male. Six young produced 

 by this union of white parents were all black. 



It is known that black color is dominant over white in the 

 guinea pig, hence this experiment shows conclusively that the 

 germ cells produced by the female were produced by the "black" 

 ovaries and were not influenced by the white body that nurtured 

 them. The experiment was undertaken to determine whether the 

 body, as the immediate environment of the germ cells, exerts any 

 influence on them and has been regarded as absolute proof that 

 this is not the case. However it is not absolute proof. In the 

 first place, not merely the germ cells but ovaries of the black 

 female remained in the white individual, so that the environment 

 of the germ cells was not wholly albino. In the second place, we 



