48 INTERNAL SECRETION 



the parathyroids of dogs and cats in their spleen. I found that 

 the subsequent removal of the thyroids and inner parathyroids 

 was not attended by untoward results. Violent tetanic symptoms 

 sometimes appeared, but these were usually transient. These 

 animals may remain for months (a dog lived for eighteen months) 

 without symptoms, but they eventually die of tetany. This 

 applies also to animals in the spleen of which two to four para- 

 thyroids from other animals of the same species have been trans- 

 planted, their own thyroid being afterwards removed. Post- 

 mortem examination shows that only cicatricial tissue remains at 

 the implantation site, the grafted parathyroids being completely 

 absorbed. 



In two experiments out of three carried out on young dogs 

 by Pfeiffer and Meyer, the parathyroids were successfully im- 

 planted in the rectus muscle, and tetany did not follow the 

 extirpation of the remaining portion of the thyroid apparatus. 



Halstead, and later Hermann and Harvey, also described the 

 successful transplantation in dogs of both their own parathyroid 

 glands and those of other dogs. The latter authors are of 

 opinion that the visceral peritoneum is a more suitable site for 

 implantation than either the muscular structure or the spleen. 



Walbaum (1903) found that after implantation of the external 

 parathyroids in the serous membrane of the stomach of rabbits, 

 the internal parathyroids being removed at the same time or later, 

 the animals lived from five to nine months. There was no tetany, 

 but there were trophic derangements, such as dermatitis, emacia- 

 tion, and arrest of growth, which in the end caused death. The 

 grafted organs generally retained their normal histological 

 character for a certain length of time, showing few and in- 

 considerable changes. Christiani, who since the beginning of 

 the nineties has carried out many hundreds of greffes 

 thyroidiennes -and parathyroidiennes with rats, finds that the 

 structure of the implanted glands remains unchanged, though 

 they at first show a slight central necrosis which is, however, 

 soon replaced by normal tissue. After two years in rats, and 

 after even five years in cats, the glands will be found to be 

 practically unchanged. 



Camus found that the parathyroid glands, when transplanted 

 into the ear of rabbits, invariably atrophied if a sufficiency of active 

 parathyroid tissue was allowed to remain in situ. 



Leischner implanted the parathyroids of rats, with a portion 

 of the thyroid tissue attached, in the abdominal wall. The 

 simultaneous transplantation of both parathyroids provoked a 

 passing tetany. The grafted organs healed in and, one to two 

 months later, the removal of the abdominal rectus muscle in 

 which they were implanted, produced tetany. 



These experiments show that transplanted glands, whether 

 of the subject of the experiment or of another animal of the same- 



