Chapter /J. 



Autogenous, Syngenesious, Homoiogenous and 

 Interracial Transplantations in Birds 



In our experiments with Addison, in which we compared the homoio- 

 transplantation of pigeon skin with the transplantation of this tissue into 

 chickens, into various mammalian species, and also into amphibia, we 

 found a marked difference between the results of homoio- and heterotrans- 

 plantation. In the former, the lymphocytes of the host were the principal 

 agent which injured and in the end destroyed the transplant, whereas, in the 

 latter it was the toxicity of the bodyfluids which injured the transplants, 

 caused a cessation of the proliferative power of the epidermis and, soon after- 

 wards, destroyed it altogether. After heterotransplantation, this destruction 

 was accomplished usually as early as during the first and second week, while 

 after homoiotransplantation it took place in some cases during the fourth 

 week, but in other cases transplants were found alive, at least partly, as late 

 as during the fifth week. 



While thus the distinction between homoiogenous and heterogenous trans- 

 plants was quite sharp, and while there was also at least some indication that 

 among the various types of heterotransplants there was, under certain condi- 

 tions, a correspondence between compatibility of the organismal differentials 

 and the degree of genetic relationship between the species, which served as 

 hosts and donors, no attempt had been made in these experiments to analyze 

 the finer differences in birds, which might be expected to exist between autog- 

 enous, syngenesious, homoiogenous and interracial transplantations. Nor 

 did the subsequent experiments of Schultz, nor those of Danforth and Foster, 

 give any information in this respect, although the latter in particular were of 

 interest from other points of view. Danforth and Foster, in experiments with 

 Leghorn and Plymouth Rock chickens, transplanted skin flaps from recently 

 hatched chicks to other chicks of the same inbred race or to other races. In 

 many cases the pieces of skin healed in permanently in chicks belonging to 

 other races, although the best results were obtained in the exchange of skin 

 between members of the same inbred race; but this may have been due to 

 accidental factors rather than to a similarity of the organismal differentials 

 between host and transplant. Danforth and Foster concluded that individuality 

 differentials exist in birds in isolated instances. However, the fact that they 

 used recently hatched chicks rather than adult birds made the recognition of 

 differences between individuality differentials more difficult, because in these 

 very young animals the reaction against strange individuality differentials 

 should be milder or, under certain conditions, lacking altogether ; in addition, 

 in these long term experiments a gradual adaptation between host and graft 

 might take place. Furthermore, the use of healing-in or lack of healing-in of 



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