Chapter I//. 

 Hormones and Individuality Differentials 



The organism is an approximately equilibrized mechanism in which 

 the maintenance of the structural autonomy of the various parts and 

 the integrity of the whole organism depend upon the inherited char- 

 acteristics inherent in these parts, in particular upon the nature of the inter- 

 acting tissues and their individuality differentials; furthermore upon their 

 state of sensitization, and upon the degree of stimulation these structural 

 units receive especially by hormones. Interaction of all these factors with one 

 another takes place, including the interaction between individuality differ- 

 entials and the hormones, and it is this last type of interaction which is of 

 interest also in our analysis of the individuality differentials. In this interac- 

 tion the endocrine function may be considered as the primary factor and we 

 may inquire how this function would be affected by changes in the individual- 

 ity differentials, or, on the other hand, .the individuality differentials may be 

 considered as the primary factor and we may inquire into the effect which 

 changes in hormone action may have on the activity and efficiency of the in- 

 dividuality differentials, especially under conditions in which two different 

 individuality differentials oppose each other. 



Hormones as such, within a wide range of their action do not possess in- 

 dividuality differentials and are independent of the latter, but the organs 

 in which they are produced and the tissues upon which they act carry these 

 differentials, and the new formation of tissues which takes place as the 

 result of the function of certain hormones, may be greatly influenced by the 

 nature of the individuality differentials of these tissues and organs; these 

 effects may be unfavorably affected by the presence of other than autogenous 

 individuality differentials. Thus we have seen that the formation of placento- 

 mata, which is controlled by the interaction between the corpus luteum hor- 

 mone and mechanical stimulation, requires the presence of autogenous in- 

 dividuality differentials if the maximum effects are to be achieved, whereas, 

 the presence of a homoiogenous differential has an inhibiting action on such 

 processes. Likewise, the grafts of endocrine glands, such as ovaries and thy- 

 roid, develop and function best in a perfect autogenous environment. 



On the other hand, under some conditions the presence or absence of cer- 

 tain hormones may affect the function and growth of organs and tissues in an 

 environment in which the individuality differentials are not entirely adequate ; 

 or the action of hormones, also, may be of significance even in the survival of 

 autogenous transplants. However, in this respect different organs seem to 

 differ as to the degree to which they are influenced by the activity of certain 

 hormones. In the organs which we have studied, the ability of hormones to 

 prevent altogether the injurious effects of not quite adequate individuality 



143 



