TRANSPLANTATIONS IN BIRDS 63 



of the preformed fibrillations of this tissue ; but under such unfavorable con- 

 ditions these cells may later perish. 



The effect of the individuality differentials of autogenous, syngenesious 

 and homoiogenous transplants on the lymphocytes in the circulating blood. 



Disharmony between the individuality differentials of the transplant and host 

 not only causes local reactions, owing to the diffusion of the individuality 

 differential substances into the area directly surrounding the transplant, but 

 according to the findings of Blumenthal, diffusion takes place also into the 

 blood vessels, and probably into the lymph vessels, from which points these 

 differentials are carried presumably to the blood-forming organs and here 

 stimulate an increased production or elimination of the white blood cells into 

 the capillaries. This occurs in birds as well as in mammals. There is, more- 

 over, a quantitative relation between the kinds of individuality differential 

 substances given off by the transplants and the kind and intensity of changes 

 induced. It may furthermore be assumed that even in the case of the local 

 reactions around the transplants these substances diffuse into the blood or 

 lymph stream and thereby contribute to the local accumulation of the white 

 blood cells ; at least the filling of the lymph vessels with lymphocytes and the 

 increased number of the latter in the blood capillaries around homoiotrans- 

 plants suggest such a process. 



Investigation of the effect of homoiogenous and syngenesiotransplants by 

 Blumenthal gave the following results : A relative and absolute increase in the 

 number of lymphocytes in the peripheral blood took place after homoio- and 

 syngenesiotransplantation, in contrast to heterotransplantation, after which an 

 increase in polymorphonuclear leucocytes occurred. The general and local re- 

 actions were found at about the same time. After homoiotransplantation of 

 the thyroid gland the maximum in the increase in lymphocytes in the blood 

 was on about the 6th or 7th day ; this was also the time when the lymphocytes 

 began to collect locally around the graft; on the other hand, the maximum in- 

 crease in the polymorphonuclear leucocytes after heterotransplantation oc- 

 curred more rapidly, namely, on the 4th or 5th day. The time when the maxi- 

 mum in the response was attained depended also upon the consistency of the 

 different tissues; this factor seemed to determine the readiness with which 

 these specific substances, possessing the individuality differentials, were ex- 

 tracted and were able to diffuse into the adjoining areas and into the circulation 

 of the host. The relative increase in the percentage of lymphocytes after 

 homoiotransplantation of thyroid varied from 13.5 per cent in the pigeon, to 

 16.9 per cent in the rat, and to 16.6 per cent in the guinea pig, and in a number 

 of experiments it exceeded 25 per cent. After heterotransplantation the rela- 

 tive increase in the percentage of polymorphonuclear leucocytes ranged be- 

 tween about 12 per cent and 26 per cent. After autogenous transplantation of 

 different organs or tissues, the average maximum percentage increase of lym- 

 phocytes showed variations between 3.3 and 6.5 per cent in different species of 

 animals ; in the pigeon there was no increase. After subcutaneous transplanta- 

 tion of inert foreign bodies or after an incision the effect on the number of the 

 circulating lymphocytes was about the same as after autogenous transplanta- 



