DIFFERENTIALS IN CLOSELY INBRED MICE 115 



preserved granulosa of follicles is not readily invaded by lymphocytes. An even 

 more striking example of such differences is to be noted in the activity of differ- 

 ent structures within the adrenal gland. Here, the degenerating yellow cortical 

 tissue attracts lymphocytes in large masses, although this reaction in its full 

 strength may occur only very late after transplantation ; on the other hand, 

 preserved strands of glomerulosa or fasciculata cells are not invaded by 

 lymphocytes. Such peculiar differences in the attraction which various tissues 

 exert on lymphocytes and which must be connected with peculiarities in the 

 metabolism of these various tissues, may prevent a complete correspondence 

 between reactions against different kinds of tissues which have been trans- 

 planted at the same time, from the same donor into the same host. 



