TUBERCULOSIS. 261 



through all of the products of the disease. Most danger- 

 ous in this respect naturally is tuberculous sputum. Of 

 less importance are the feces in cases of intestinal tuber- 

 culosis, the urine in cases of genito-urinary tuberculosis, 

 and the pus in cases of bone-tuberculosis. By means of 

 the sputum of tuberculous patients who, instead of using 

 a spit-cup, expectorate upon the floor or into handker- 

 chiefs, the tubercle-bacillus is disseminated in the environ- 

 ment of the patient. The microorganism exhibits consid- 

 erable resistance to drying, and in dried sputum, for in- 

 stance, retains its vitality and infectivity for six months. The 

 dried and powdered sputum is readily carried as dust in 

 currents of air, and the tubercle-bacilli may in this way 

 enter the air-passages of other individuals and there give 

 rise to infection.* 



The credit for pointing out this mode of distribution 

 for tubercle-bacilli belongs to Cornet, who was able to in- 

 fect guinea-pigs with tuberculosis by means of dust from 

 the walls, the floors, the furniture, etc., of hospital -wards 

 and dwelling-apartments occupied by tuberculous patients 

 careless with regard to the disposition of their sputum. 

 Dust from localities not invaded by tuberculous patients 

 invariably proved free from tubercle-bacilli. 



Reference must, however, be made at this place to the 

 observations of Kitasato, who showed by culture-methods 

 that not rarely the tubercle-bacilli in the sputum of tuber- 

 culous patients have died. To what extent current views 

 as to the danger from tuberculous sputum must be quali- 

 fied by this fact can not yet be determined with certainty. 



A further source of infection, whose importance must 

 not be underestimated, is constituted by the milk of tuber- 

 culous cows. Tuberculosis in cattle is a manifestation of 

 the activity of the tubercle-bacillus a tuberculous process 

 that differs from human tuberculosis only in the occurrence 

 of calcification coincidently with caseation. The milk of 

 cows suffering from tuberculosis contains tubercle-bacilli 



* According to observations made by Fliigge, the larger particles of sputum, 

 both in the fresh and in the dry state, are less dangerous. The main danger is 

 believed to reside in the fine particles of fluid that are ejected simultaneously 

 with the sputum, and which may float in the air for a long time and be inhaled 

 by those with whom the patient comes in contact. These small drops, as 

 Fliigge has demonstrated experimentally, contain bacilli. To what extent 

 this fact should influence the attitude of the physician with regard to the 

 sputum from the prophylactic standpoint (p. 266) can not yet be defined. 



