252 EDUARD TJHLENHUTH 



usually hatched on the same day. Whether or not their origin 

 was from the same mother was not noted. The operations were 

 performed from the 6th to the 22d of July, 1916. The results 

 of this series (Series XXV) are described in the following pages. 



2. The Results 



a. The metamorphosis of the skin grafts. Not all 23 pairs 

 gave conclusive results, as was to be expected from the character 

 of the experiments. In six pairs one of the two individuals died 

 before metamorphosis; in six other pairs the development of 

 those characteristics used as indicators of metamorphosis showed 

 some irregularities which prevented final conclusive results. 

 In the remaining eleven pairs the result was conclusive. Ac- 

 cording to this the experiments may be divided into three groups. 



1. In six pairs one animal died a short time after the opera- 

 tion, the remaining animal was nevertheless watched and it was 

 observed that with one exception (experiment 13) where no 

 result was reached at all, the development of the graft pro- 

 ceeded simultaneously with the development of the host. 



In experiment 1 the animal was set on land-condition on 

 September 1, 1916 ; 4 the first greenish spot on* skin graft appeared 

 on September 2; the network of the host was separated into 

 greenish spots on September v 5. In host and graft the spots 

 assumed more definite outlines on September 18 and turned 

 yellowish on October 2; on October 3, host and graft appeared 

 cinnamon after having become gradually darker and darker. 

 Both were still darker on October 31; no further examination 

 could be made as the animal died. 



In experiment 3, host and graft both turned gradually darker 

 and darker until the animal was set on land-condition on Sep- 

 tember 7. On September 9, host and graft had developed green 

 spots. 



4 All observations and notes from the end of July to October 2 were made by 

 Mr. N. Anderson with the aid of a detailed plan given to him for this purpose. 

 All observations and notes previous and subsequent to this period were made 

 by the author himself. On October 3 the results found at this time were compared 

 with Mr. Anderson's notes and were found to be in accordance with them. 



