398 BIOLOGY: GENERAL AND MEDICAL 



ment changed; that is, the fibrillar tissue meets fibrillar 

 tissue, the adipose tissue meets adipose, and the derm 

 meets derm. 



The more heterotropic the transplantations, the less 

 the probablilty of success. Transplantation is not 

 much practised in human surgery, but enough experi- 

 ments have been performed upon the lower animals in 

 the laboratory to hold out considerable hope of future 

 success. It was found by Hunter and Duhamel that 

 the spur of a young cock could be successfully trans- 

 planted to its comb where it continued to grow and 

 eventually attained its full size. 



Ribbert transplanted the mammary gland of a guinea- 

 pig a few days old to a position upon its head where the 

 graft took well without absorption. The animal grew up 

 and subsequently bore young, and it is interesting to note 

 that the transplanted mamma secreted milk during the 

 period of lactation. 



Kocher, in 1883, transplanted thyroids in dogs with a 

 certain amount of success; and Schiff, in 1884, obtained 

 temporary benefit and the prevention of cachexia 

 strumipriva in human beings by grafting thyroid tissues 

 after removal of the thyroid gland for disease. 



Von Eiselberg (1892) transplanted one-half of a cat's 

 thyroid into its abdominal wall, waited until the wound 

 had healed, and then transplanted the other half into 

 the abdominal wall or cavity. The animal bore the 

 operation well and lived on, the grafts remaining. When 

 the grafts were later excised, tetany quickly developed, 

 and the animal died. These experiments show that 

 the thyroid is able to persist and functionate in a new 

 environment. 



The experiment has since been repeated many times, 

 and it is now certain that the transplanted thyroid can 

 remain functional during the entire remainder of the 

 animal's life. 



The success or failure of the transplantation seems to 

 depend in large measure upon the physiological necessity 



