636 THE INTERNAL SECRETIONS AND IMMUNITY. 



seems to elucidate is the modus operandi of tuberculin in Koch's 

 tuberculin test. Why does fever appear when this substance 

 is injected only (it might be more proper to say "mainly") in 

 individuals who -are suffering from tubercular disease? Why 

 is it also harmless for healthy animals, but violently toxic for 

 tuberculous animals, going so far in these sometimes as to 

 produce death? A rise of 2 F. or more above the normal 

 temperature is brought about in tuberculous subjects, but if 

 another injection be made within a period covering sometimes 

 as much as two months, a reaction is not to be obtained. In 

 the light of what has previously been said as to the predilection 

 of the adrenals per se for tuberculosis, as observed in con- 

 nection with Addison's disease, it seems probable that these 

 organs must always be more or less organically diseased in any 

 but the earliest stage of practically all cases: a complication 

 which would explain the failure of Koch's tuberculin. Even 

 leaving out of all consideration this important element of the 

 tubercular process and considering the pulmonary, glandular, 

 osseous, etc., lesion that may be present as the only pathological 

 existing condition, the symptoms caused by the injections of 

 tuberculin seem easy of explanation. 



In the healthy subject the glands are in their normal 

 functional state and the dose of tuberculin introduced into 

 the circulation is insufficient to cause them to assume unusual 

 activity. In the -tuberculous subject, on the other hand, the 

 diseased area is the source of toxins of various kinds which are 

 constantly stimulating the adrenals to unusual activity. The 

 dose of tuberculin does not alone under these conditions enhance 

 suprarenal activity, but it represents an addition to the kindred 

 toxin present; united, tuberculin and poison thus give rise to 

 an exacerbation of the glandular functions which becomes 

 manifest by the febrile state induced and other symptoms of 

 adrenal overactivity. 



Spurred to unusual energy by the tuberculin, the adrenal 

 system excites correspondingly active metabolism in all cellu- 

 lar structures, including those endowed with leucocytogenesis. 

 Phagocytes and alexins are produced in profusion, the fixed 

 endothelial and the connective-tissue cells contributing their 

 share to the production of the latter, and there is thus con- 



