90 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



genous relationship between the individuality differentials of donor and host, 

 but in another experiment in family 32, after 37 days the grade was 3/3 — , 

 corresponding to a very good syngenesio-reaction. In family 13, the grades 

 varied between 3— and 3— /2 + , even if both donor and host belonged to the 

 20th inbred generation. These grades correspond to good syngenesio-reactions, 

 indicating the existence of some differences in the constitution of the individu- 

 ality differentials. They may be due to the fact that, in family 13, there was a 

 greater possibility that the number of direct common ancestors of different 

 individuals was not so large as in the other families, and this may explain the 

 lack of autogenous conditions, at least in some cases. In family 2, one grade 

 was 3— (2-17 -> 2-17), in another experiment it was 3-/2+ (2-18 -» 2-16), 

 an indication of a lack of identity of the individuality differentials. These re- 

 sults were, on the whole, confirmed by some experiments in which the exam- 

 ination took place at a later date. Thus, in family 13, after 5 months and 12 

 days, the grade was 2 (unfavorable syngenesio-reaction) — after Zy 2 months, 

 it was 3. In family 2 (or 2N), autogenous conditions were found in these 

 experiments. 



These experiments indicate that in some families the autogenous condition 

 was closely approached but was not yet quite attained, while in other families 

 considerable progress had been made toward homozygosity, but the grades 

 corresponded still to good syngenesio-reactions. In different experiments the 

 results varied somewhat in various families. It is of special interest to note 

 that the lymphocytic reaction may appear only at a late stage following trans- 

 plantation, but that the lymphocytes may then exert a very destructive effect. 

 Together with the late lymphocytic reaction there may occur a secondary 

 slight proliferation of connective tissue in the transplant. However, the aver- 

 age grades in transplantations betwen guinea pigs belonging to different 

 litters in these inbred families were higher than the average grades in trans- 

 plantations between brothers or sisters in non-inbred families. 



(2) Successive transplantations of thyroid into the same inbred family. 

 These gave similar results. In family 32 : First, transplantation for 37 days ; 

 second, transplantation to brother for 4 months, 9 days: grade 3-/3, which 

 closely approaches results in autogenous transplantations. In family 13 : First, 

 transplantation for 31 days; second, transplantation for 32 days: grade 2, 

 which corresponds to a severe syngenesiotransplantation ; but in this case, 

 donor and last host had only seven generations of brother- sister matings in 

 common. 



(3) Multiple simultaneous transplantations. In four experiments with 

 families 13 and 32, several pieces either of thyroid gland alone, or of thyroid 

 and various other organs (spleen, liver, adrenal, pancreas) were transplanted 

 simultaneously : examination took place between 27 and 37 days. The grades 

 varied between 3/3— and 3 + , therefore between the reactions in favorable 

 syngenesious and in autogenous transplantations. The results here were as good 

 in family 13 as in family 32. In nine additional experiments with families 32, 

 2 and 13, in which the examination took place 4 months, 9 or 12 days after 

 transplantation, and in which thyroid, cartilage-fat tissue, bone and bone mar- 



