TRANSPLANTATIONS IN BIRDS 61 



ens all behave in about the same manner, although some very slight differences 

 may exist. Thus while in homoio- and interracial transplantations the intensive 

 lymphocytic infiltration set in about 10 to 11 days following transplantation, 

 in syngenesiotransplantations it appeared a few days later, namely, after 13 

 days. Similarly, follicle-like accumulations of large lymphoblast-like cells, 

 which were found in these grafts in chickens and which aided the smaller 

 lymphocytes in the destruction of the strange tissues, were seen in the first 

 two types of transplantations after 13 days, and in syngenesiotransplantations 

 only after 16 days. While these differences in the time of the appearance of 

 such cells are very small, still they are in agreement with the findings of H. T. 

 Blumenthal in regard to differences in the time when the lymphocytes are in- 

 creased in the circulating blood after subcutaneous transplantation of various 

 pieces of tissue. It might be expected that the rapidity with which these 

 changes in the lymphocytes and lymphoblast-like cells become manifest locally 

 and the rapidity with which the increase in the lymphocytes takes place in the 

 blood, should be greater in those cases where the individuality differentials, 

 diffusing into the surrounding tissue or into the blood vessels, showed a 

 greater degree of strangeness and therefore also a greater toxicity. 



In contrast to these types of transplantations, after autogenous trans- 

 plantation of skin and xiphoid cartilage with the surrounding tendon-like 

 tissue, collections of lymphocytes are lacking altogether or only very small 

 clumps of these cells, arranged around the vessels, can be seen. If keratin 

 from the transplanted skin has been separated from the epidermis by the 

 connective tissue, a few lymphocytes quite commonly collect around such 

 foreign bodies. Lymphocytes are either absent or only very small collections 

 form around particles of fat tissue transplanted with the cartilage or around 

 some foreign bodies. 



A very interesting occurrence is that sometimes around and in these autog- 

 enous transplants a disequilibration between the host connective tissue or 

 the transplanted tendon connective tissue and the cartilage takes place. Then 

 connective tissue cells move toward the piece of cartilage and surround it, 

 giving rise to a capsule. Often they penetrate also into the periphery of the 

 graft in the direction of the fibrillar structure of the long axis of the cartilage 

 cells. In some cases, turning approximately at right angles to the long axis 

 of the cartilage cells, they penetrate slightly into the interior of the cartilage. 

 Moreover, these connective tissue cells possess the power to split and dissolve 

 the cartilage, and in doing so, they sometimes become larger. Either in the 

 cartilage or in the surrounding dense fibrous tissue some cells, coming from 

 the connective tissue, may change into epithelioid and giant cells, especially 

 in places where an obstacle interferes with their progress. Connective tissue 

 cells also accompany certain vessels which grow into the cartilage. But on 

 the whole, the transplanted cartilage, as well as autotransplanted fat tissue 

 and bone marrow with myelocytes, is well preserved. 



There is a remarkable correspondence between the reactions of the host 

 connective tissue towards autotransplanted cartilage and towards autogenous 

 epidermis transplants when the latter do not close to a cyst-like or to a flat 



