METAMORPHOSIS OF AMPHIBIAN ORGANS 271 



13 and 14; this condition was only little changed, when the 

 animal died. Hence, in experiment 34 metamorphosis of the 

 grafted eye could not take place because the host did not meta- 

 morphose, while in experiment 33 the grafted eye, though be- 

 longing originally to the same animal A as the grafted eye of 

 experiment 34, was forced into metamorphosis by its host at 

 least three months earlier than experiment 34. 



B. HETEROPLASTIC TRANSPLANTATIONS FROM LARVAE OF AMBLY- 

 STOMA TIRGINUM TO AMBLYSTOMA PUNCTATUM 



The object of these experiments was to ascertain whether or 

 not organs of one species could metamorphose on the body of 

 another species. Eyes and pieces of skin were grafted from 

 A. punctatum to A. tigrinum. The experiments actually showed 

 that eyes as well as skin are able to metamorphose even when 

 grafted to another species, and that they metamorphose at the 

 time that the host metamorphoses. 



/ . Material and method 



The technique of operations employed in these experiments 

 (series XXVI) was the same as that used for series XXV. The 

 skin of one half of the head including the eye was taken off from 

 a larva of A. punctatum and grafted to the region just back 

 of the shoulders of a larva of A. tigrinum, after a piece of skin 

 the size of the graft and a small amount of tissue of the musculus 

 longissimus dorsi had been cut out from there. 



The general method was somewhat different from series XXV, 

 as the experiments were not arranged in pairs; the animal A 

 from which the graft was taken being a different individual for 

 each experiment. The left eye" of individual A (A. punctatum) 

 was grafted to individual X (A. tigrinum), X being the experi- 

 mental animal which alone was kept alive and examined from 

 time to time. 



It was of course, impossible to compare the developmental 

 stages of the grafts with the developmental stages of the host 

 with such exactness as in series XXV, since the changes of the 



