476 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



which are concerned in the function of these organs are specifically adapted to 

 one another because they carry the same organismal differentials, and in which 

 tissues or substances bearing strange organismal differentials call forth antago- 

 nistic reactions on the part of the host. However, in addition there may be 

 active in this correlation between the phylogenetic relationship of animal 

 species and the interaction of tissues and organs and of substances concerned 

 in the functions of organs and tissues, other functions of tissues and organs, 

 in which the organismal differentials are not involved and in which the active 

 compounds may be of a less complex nature. However the finest and most varied 

 examples of specific adaptations are furnished by the interactions between 

 transplanted tissues and hosts which we have discussed in the chapters of the 

 first part of this book. These experiments furnished also the basic data from 

 which the concepts of organismal and individuality differentials and of autoge- 

 nous tissue equilibria have developed. 



