94 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



transplantations of this kind were carried out; but in one of these, the ex- 

 amination took place as early as 10 days after transplantation. Omitting this 

 case, there remain 13 experiments in which the examination took place between 

 20 and 40 days. In the large majority of these transplantations the hybrids 

 were composed of families 13y and 2, but in a few instances, families 35 and 

 32 were parents of the hybrids. We may arrange these transplantations accord- 

 ing to the similarity or difference in the generations of brother-sister matings 

 of the two component parents in donor and host. In one set the parent families, 

 13y and 2, which entered into the hybrids in donor and host, belonged to the 



same generations: (Cy-0 j^J' 4 -^Cy-0 jl% (21 days) ; grade 3. In four 

 transplantations, the generations were the same in one inbred family but differ- 

 ent in the other family: CP-0 jj^" 2 ^ -+CP-0 H^J 5 (20 days) ; grade 2.75. 



The grades in the other three transplantations of this kind were: 3, 3.25, 2.75 ; 

 the average grade was 2.94. In the remaining eight experiments, in each case 

 the parents composing the hybrids belonged to different generations. The 

 grades were: 1.75, 1.75, 1.75, 1.25, 1.75, 1 (hybrids between families 13y and 

 2), 2.75 (hybrids between families 2 and 35), and 3.25 (hybrids between 

 families 32 and 35). Again the presence of family 13 in the hybrids seemed to 

 intensify the severity of the reaction, while in the combination between fami- 

 lies 32 and 35, the result corresponded to that found after autogenous trans- 

 plantation. The average grade in the six transplantations into which family 

 13y entered was 1.54, which approached that of a homoiogenous transplanta- 

 tion. 



H. Transplantation in hybrids in which one of the two parent families 

 was the same in donor and host, while the other parent family was different. 

 One hybrid was composed of families 2 and 13y, while the other hybrid, either 

 host or donor, was composed of families 13y and 35. Three transplantations 

 were carried out and examination took place after 19 to 21 days. The grades 

 were: 1.87, 2.12, 1, and the average grade was 1.69, which represents a mod- 

 erate homoiogenous reaction. The result is similar to that obtained in the 

 transplantations between hybrids 2 and 13y, in which both parent families be- 

 longed to different generations. 



Series III. Transplantations between guinea pigs during early stages in 

 inbreeding. 



Two short series of experiments were carried out with guinea pigs which 

 had been inbred for five to six generations by brother-sister matings at the 

 Caworth Farms in New York. We shall briefly mention*these transplanta- 

 tions, because they indicate that in contrast to the experiments with guinea 

 pigs which had been subjected to close inbreeding for from about 15 to 27 

 generations, no definite progress towards an autogenous condition of the 

 individuality differentials had as yet been made. Guinea pigs from two strains 

 (CP and Connaught), in each of which there were several inbred families, 

 were used. The initial weights varied between 225 and 310 grams and 

 examination took place after 30 days. Thyroid, cartilage, fat tissue and 

 muscle or thymus were transplanted. 



