HORMONES AND INDIVIDUALITY DIFFERENTIALS 149 



hormone which is able to stimulate the transplant. These hormones act pri- 

 marily on the parenchyma of the graft, stimulating its increased growth and 

 function, and such increased activity of the glandular tissue may secondarily 

 stimulate the activity of the stroma and especially also its vascularization, 

 which then further aids the growth and power of survival of the graft. 



It may therefore be stated that hormones may influence in various ways 

 the effects of the individuality differentials on the fate of a transplant. By 

 stimulating growth processes in the latter, hormones tend to neutralize the 

 damaging action of strange differentials, and by depressing these growth 

 processes they may intensify the effect of unfavorable differentials. 



