Influence of Environment 



231 



as well as in other respects, R. sylvatica being more deeply pig- 

 mented than R. palustris. In the grafted tadpoles each half 

 preserved its own peculiarities even up to the adult condition 

 (Fig. 85). 



A still more striking case of the persistence of heredity in spite 

 of environmental changes is found in experiments in which the 

 ovaries are removed from one variety of animal and transplanted 

 to another variety. Guthrie made such transplantations in the case 

 of fowls and concluded that there was some influence of the fos- 

 ter mother upon the transplanted ovary, but Davenport, who re- 

 peated his experiments, was unable to confirm his results. Fi- 

 nally Castle and Phillips furnished the most conclusive demon- 



FIG. 85. 'GRAFTED FROG EMBRYOS, anterior part, Rana sylvatica, posterior 

 part, R. palustris. In later stages, and even in the adult condition, the two 

 parts preserve their peculiarities. (From Harrison.) 



