THE PHENOMENA OF INFECTION 461 



Indian has succumbed to this disease is a striking illustration, 

 and Calmette has recently collected additional evidence 

 on this point. He states that tuberculosis is being widely 

 disseminated among peoples who have until recently been 

 free from it. The world-wide wanderings of the white man 

 are carrying the disease to every people, from the Laplander 

 and Esquimaux of the Arctics to the negroes and Malays 

 of the tropics. Iceland, the Faroe Islands, and the steppes 

 of Russia are being infected, and in these new regions 

 tuberculosis exists in its most speedily fatal forms. The 

 same author points out that recently discovered methods 

 for the recognition of this disease, even in latent states, 

 shows that among Europeans not more than 7 or 8 per cent, 

 reach more than twenty years of age without receiving the 

 infection. Those who survive the first infection become 

 more or less immune, and after that develop, when they do 

 acquire the disease, the more chronic forms. 



Romer 1 concludes that the less widely tuberculosis is 

 distributed among a people the greater is the case mortality, 

 and the wider the distribution the smaller is the case 

 mortality. 



Still another fact of importance is that the most speedily 

 fatal forms of tuberculosis, such as the miliary and menin- 

 geal, are more frequent among children than among adults. 



There is another matter of much importance in this 

 connection which we must discuss. We have found the 

 tubercle bacillus highly resistant to lytic agents, and it 

 appears that its long experience as a parasite has led it to 

 protect itself with deposits of wax and fat, but proteolytic 

 enzymes digest the most firm proteins. Friedberger has 

 found that at least some strains of this bacillus are digested 

 by the serum of healthy guinea-pigs, and the researches of 

 Markl, Bail, and Kraus and his students have shown that 

 tubercle bacilli placed in the peritoneal cavity of tuberculous 

 animals respond to Pfeiffer's reaction. Some strains are 

 dissolved in the peritoneum of healthy guinea-pigs, but 



1 Beitrage z. klinik d. Tuberk., 1912, xxii, 301. 



