XII. THE EVOLUTION OF MANKIND AND ITS FUTURE 433 



or adrenocorticotrophic hormone (ACTH) has been found to affect the 

 course of virus infection to the disadvantage of the host. This has 

 been demonstrated for influenza and mumps virus in chick embryo and 

 in mice, for poliomyelitis and Coxackie virus in mice and hamsters, 

 vaccinia in guinea pigs (123) (124). 



The administration of these hormones, however, is known to be 

 inhibitory to inflammatory or allergic reactions. For example, it has 

 been reported that ACTH and cortisone reduce the febrile response of 

 rabbits to typhoid vaccine and that cortisone markedly reduces the 

 temperature of patients with typhoid fever (125) (126). Moreover, it 

 has been shown that these hormones can suppress the febrile response 

 of rabbits to bacterial endotoxin (127). Cortisone and ACTH are known 

 also to inhibit cellular inflammatory reactions to a wide variety of 

 other irritants including burns, trauma, and various chemical agents 

 (128\ 



Inflammatory reactions against bacterial infection may thus be pre- 

 vented by the administration of cortical hormones. However, replica- 

 tion of the bacterial pattern in the host, like that of the viral pattern, 

 seems to be accelerated by these hormones. Thus, cortical hormones 

 have been shown to increase the susceptibility in a number of hosts 

 of many unrelated bacterial diseases (129). Effective doses of ACTH 

 or cortisone are usually associated with evidence of increased multi- 

 plication of the pathogens and more wide spread dissemination, al- 

 though adrenal cortical hormones are not stimulatory to bacterial 

 growth bt vitro (128). This seems the case even with tuberculosis. 

 Clinical experience suggests that administration of cortisone may 

 reactivate an apparently healed tuberculosis infection in man (130). 

 Laboratory studies with various animal infected with tubercle bacilli 

 have shown that the administration of cortisone causes a more 

 extensive diseases than that exhibited by controls. 



The favourable effect of the heightened function of hypophysis upon 

 tuberculosis may, therefore, be not dependent upon the hypersecretion 

 of cortisone, but upon the involution of thymus and other lymphatic 

 organs which favour tuberculosis as already pointed out. It should 

 be mentioned, however, that although cortisone exerted its deleterious 

 effect upon tuberculous animals, corticotrophins of hypophysis could 

 be administrated in excess of human dose levels without harmful effect 

 and was deleterious only at levels so high as 20 times human doses 

 (131). 



Not only tuberculosis but the infectious diseases of bacterial origin 

 in general appear rather rare in civilized people, in contrast to the 

 high prevalence of some virus diseases among them, despite the above 

 mentioned fact that the susceptibility of hosts to bacterial diseases is 



