SYNGENESIOTRANSPLANTATION 



73 



should pass from the zone of syngenesio-relationship and reactions to the 

 autogenous zone; but in reality this does not seem to be fully accomplished. 

 A closely inbred strain is a strain of brothers and sisters, which are very 

 similar in genetic constitution. 



After these introductory remarks, we shall consider the results of syn- 

 genesiotransplantation in the rat and in the guinea pig, and then we shall 

 analyze the interaction of the individuality differentials observed in trans- 

 plantations in closely inbred strains of rats, guinea pigs and mice. 



(a) Syngenesiotrans plantation in rats. We have referred already to some 

 experiments in which the reactions against transplants from brothers or sisters 

 were, on the average, milder than the reactions against homoiogenous trans- 

 plants, but on the other hand there were some instances in which no sharp 

 distinctions between the individuality differentials of brothers and sisters and 

 those of not closely related individuals could be established. Thus in the mutant 

 Wistar rats, a special strain developed by Dr. Helen Dean King, the 

 syngenesio-reactions were milder than the reactions against transplants from 

 non-related rats of the same strain, if the examination of the grafts occurred 

 12 and 16 days after transplantation, but no difference was found after 20 

 days. Also in some other experiments the grades in syngenesiotransplantations 

 could approach closely the average grades in homoiotransplantations, although 

 their average reaction was still somewhat milder. 



Two series of experiments will now be discussed — one made in 1918 (series 

 I), and the second made in 1927 (series II), in which we compared the fate 

 of various organs such as skin, ovary, uterus, spleen, liver and thyroid after 

 various types of syngenesiotransplantation and of homoiotransplantation. 

 More than one organ, as a rule, was transplanted into each host. The average 

 grades obtained in these series are given in the following table I. 



TABLE I 



In the second series it was thought unnecessary to carry out autogenous 

 transplantations, because these did not vary significantly in different experi- 

 ments. In both series the grades were better in the various kinds of syngenesio- 

 transplantations than in homoiogenous transplantations, and intermediate be- 

 tween those obtained in autogenous and homoiogenous transplantations. As to 

 various types of syngenesiotransplantations, no consistent differences were 

 found and those that were noted were not of the same kind in the first and 

 second series. 



