TRANSPLANTATIONS 47 



the same after homoio- and after allotransplantation, these growth processes 

 were less intense after homoiotransplantation and, instead, degenerative 

 processes predominated, largely due to the activity of lymphocytes and con- 

 nective tissue. But there was here also a primary injury of the transplant by 

 homoiotoxins carried to the graft by the bodyfluids, which corresponds to the 

 rinding of Hesselberg in the transplanted thyroid of the guinea pig, and which 

 has been observed by us also in this species in transplanted unstriated muscle 

 tissue of the uterus and in the placentoma formation in transplanted pieces of 

 uterus. The peculiarity of the growth processes in muscle grafts, which tend 

 to repair the degenerative processes, consists in the fact that they have to 

 contend with factors unfavorable to growth, similar to those which are found 

 in liver tissue or in those parts of the epidermis which are farther removed 

 from the source of nourishment, or in the connective tissue in the neighbor- 

 hood of foreign bodies. 



8. In experiments carried out with Hesselberg and Kerwin, autogenous 

 and homoiogenous transplantations of the uterus were compared. Pieces of 

 uterus were transplanted either into subcutaneous pockets in the abdominal 

 wall or in the ear of the guinea pig. The latest period at which homoiogenous 

 pieces were found in pockets in the ear was after 16 days, and in the abdominal 

 wall, after 24 days. In the former, conditions for the survival of the transplant 

 are more unfavorable than in the latter;, at later periods, only hyaline tissue 

 with some clusters of lymphocytes were found as remnants of the homoio- 

 transplants. The autotransplants were well preserved after 35 days and would 

 presumably have lived indefinitely. At that time they showed good preservation 

 of the uterine surface epithelium and the glands, in both of which there was 

 mitotic proliferation; strands of connective tissue separated groups of glands, 

 without compressing them, because the connective tissue remained cellular- 

 fibrillar or myxoid near the epithelium, without becoming fibrous ; also, the 

 unstriated muscle tissue was well preserved and in connective tissue as well as 

 in unstriated muscle occasional mitoses were found. 



Three periods can be distinguished as far as the fate of these transplants 

 is concerned. In the first five or six days there is no marked difference between 

 autogenous and homoiogenous transplants. During the second period, lasting 

 from the 6th to the 20th day, differences develop between the autogenous and 

 homoiogenous tissues, and in the third period the latter are in the process of 

 destruction, while the former are well preserved. In both auto- and homio- 

 transplants the tissue is shrunken during the first few days, owing to the in- 

 sufficient nourishment provided during this period ; they not only recover from 

 this condition later, but a new formation of tissue, as indicated by the occur- 

 rence of mitoses in various tissues, takes place. Also, the connective tissue 

 recovers ; it has a myxoid, cellular character near the epithelium and it shows 

 mitoses. A part of the connective tissue is derived from the transplant, but 

 other growing connective tissue has its origin in the host. The second period 

 begins at about the 6th day, and on the 7th day, when the transplanted uterine 

 epithelium forms a cyst with papillae, differences between the autogenous 

 and homoiogenous transplants set in. Mitoses are found in the cellular-myxoid 



