108 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



tissue) to strange strains (AKA, Old Buffalo and C) were made, as usual 

 severe homoiogenous reactions approaching grade 1 were obtained. 



The data in table I show a very good correspondence in group I and group 

 II, and their significance is thereby increased. In addition to the conclusions 

 already discussed, it may furthermore be stated that transplantations from 

 parents to hybrids do not correspond to autogenous but to syngenesiotrans- 



TABLE I 



Group I Group II 



Inter-strain transplantations 



Intra-strain transplantations 



From hybrid Fi to parent strains 



From hybrids Fi to actual parents 



From parents to hybrids Fi (children) 



From parents to hybrids Fi (not actual children) 



From hybrids Fi to brothers 



From hybrids F x to other hybrids Fi (not brothers) 



plantations, and that transplantations from hybrids to parents seem to give 

 somewhat higher grades than the average homoiotransplantations in not inbred 

 strains, and inter-strain transplantations in inbred strains. These facts, to- 

 gether with the better results obtained in transplantations between hybrid F x 

 brothers than in those between parents and hybrid F lf suggest the presence of 

 a considerable number of genetic factors as determiners of the individuality 

 differentials, and they also confirm the conclusion that the strains which were 

 used for hybridization had not yet attained a completely homozygous condi- 

 tion. 



Besides these transplantations between parents and hybrids F 1 into which 

 two inbred strains had entered, we carried out some experiments in which 

 transplantations were made from the second generation of hybrids (black 

 C57xA)F 2 and (tan C57xA)F 2 to their parents, which were hybrids F lt and 

 to their grandparents, C57 and A, and also the reciprocal transplantations; 

 in addition we grafted tissues from some F 2 hybrids to their brothers. The 

 results obtained may be summarized as follows : 



(1) From (black or tan C57xA)F 2 to parent hybrids F 1 : mostly syngenesio- 

 reactions. 



(2) From (black or tan C57xA)F 2 to grandparents (C57 or A) : mostly 

 homoio-reactions. 



(3) From (black or tan C57xA)F! to hybrid F 2 children : mostly syngenesio- 

 reactions (somewhat less favorable than those in 1). The reactions in (1) and 

 (3) are intermediate between those from parents to F x hybrids and from F 1 

 hybrids to parents. 



(4) From (tan C57xA)F 2 to brothers: results intermediate between 

 syngenesio- and homoiogenous reactions (average grade 2.05). These are less 

 favorable than those obtained in transplantations from hybrids F 1 to brothers. 

 In general, the results in these various transplantations in which hybrids F 2 



