I032 



TUBERCULIN AND THE TUBERCULIN REACTION 



the animals are killed several days to several months later, no significant lesions are 

 found in the perfused kidneys. Similar perfusion, on the other hand, of the kidneys 

 of tuberculous swine leads to pronounced degenerative changes throughout the kid- 

 neys, and extensive acute, followed by subacute and chronic, inflammatory manifes- 

 tations in the glomeruli. In the light of these experimental results a statistical study 

 which I have carried out with Miss Robey on the relation of pulmonary tuberculosis 

 to kidney changes, in which chronic nephritis was found to occur somewhat more 



Fig. 6. — Hematogenous tubercle in the testis of a tuberculous guinea pig with atrophy of the 

 surrounding seminal tubules, which may be interpreted as a tuberculin reaction (cf. Fig. i). 



frequently in tuberculous than non-tuberculous bodies within the same age groups, 

 suggests that spontaneous intrarenal tuberculin reactions may be a factor in the pro- 

 duction of mild grades of chronic nephritis. Figures 7 and 8 illustrate the types of 

 lesion produced on injection of tuberculin protein into the renal arteries of tuberculous 

 pigs. 



RECAPITULATION 



Tuberculin, to use the name originally employed for those preparations from 

 tubercle bacilli which elicit a specific inflammatory reaction in tuberculous animals, 

 in whatever form used, depends for its action upon the presence of a specific active 

 principle. Exhaustive chemical studies bear out the original contention of Koch that 

 this substance is of protein nature. Disintegration of the protein molecule concerned 



