90 



Scientific Proceedings (8i). 



A number of animals died before results were obtained; but 

 in about ten pairs X did not metamorphose when Y did. In this 

 case the grafts did metamorphose simultaneously with their respec- 

 tive hosts but in consequence they did not metamorphose simul- 

 taneously with each other as they would have done if left with the 

 animal A. As X and Y were about of the same age, the differences 

 were mostly slight, ranging from 3 to 28 days. But in the pair 

 33-34, the animal 34 did not metamorphose for some reason and 

 was still larval in January, when it was subjected to a new opera- 

 tion and died. In this animal the skin graft as well as the eye 

 graft also remained in an entirely larval condition. The other 

 piece of skin and the other eye originating from the same animal 

 A as the grafts of the Exp. 34 had, on the other hand, metamor- 

 phosed already at the beginning of September, four months after 

 which time the graft of Exp. 34 was still larval. 



On October 19 both animals were photographed and painted. 

 Fig. 5 shows animal 33; it is fully metamorphosed and black 

 and its spots are bright and yellow. The graft is also meta- 

 morphosed and has developed three spots. In this case the 

 graft's spots are almost orange and quite different from the host's 

 spots, indicating particularly well their different origins. This is 

 also interesting because it shows that the specific characteristics 

 of the graft have not been changed by the host, though the time 

 of metamorphosis has been so thoroughly influenced by the host. 

 Fig. 6 shows Exp. 34, the other animal of this pair. It is 

 still larval, having not even developed the network. The graft 

 can be plainly seen. It is according to its different origin, slightly 

 different in shade, but in the same color stage — of an even brown 

 color. The eye is also larval, as it still shows the yellow ring 

 unbroken. Both animals have been preserved in formalin. You 

 will easily see the spots of the skin graft in animal 33; the skin 

 graft of animal 34 has been removed from this animal and grafted 

 to a larva of A. opacutn, which is preserved in formalin also; 

 in examining it you will notice the uniform brown coloration of 

 the graft and the entire lack of any network or spots, — four months 

 after the graft on animal 33 was metamorphosed. 



Finally I would like to mention that this agent which causes 

 metamorphosis in the skin is by no means a specific substance; 



