MYCOBACTERIACE^ : THE TUBKRCLE BACILLUS 325 



disease may remain localized for years in a single lymph gland or it 

 may extend rapidly causing marked emaciation and death of 

 the animal. The bacilli escape from the living bovine animal 

 most commonly in the feces/ sometimes in the mucus and spray 

 from the nose and mouth, in the uterine discharge and in the 

 milk, and of great importance is the fact that animals may be 

 excreting the bacilli without showing any gross evidence of the 

 presence of the disease. Tuberculin is extensively employed in 

 the detection of tuberculosis in cattle. A dose of 0.2 to 0.5 

 gram diluted with 9 volumes of 0.5 per 'cent carbolic acid is in- 

 jected subcutaneously at the side of the neck. The typical 

 positive reaction includes a rise in tempierature of 2° or 3° F. 

 over that of the previous day. The test is very accurate when 

 positive but not so reliable when negative. Tuberculous animals 

 should be segregated from healthy animals and food products 

 from them used only after effective disinfection, or they should 

 be slaughtered under inspection. 



Great interest has been manifested in the question of suscep- 

 tibility of man to the bovine tubercle bacilli and the solution 

 has been reached by isolating bacilli from human tissue and identi- 

 fying them. Park and Krumwiede^ have summarized the results 

 of 151 1 such examinations, and conclude that somewhat less than 

 10 per cent of the deaths from tuberculosis in young children 

 are due to the bovine tubercle bacillus, while in adults infection 

 with this bacillus is much less frequent. 



Bacillus Tuberculosis var. Gallinaceus (Avium) . — This variety 

 occurs particularly in the tuberculous lesions of barnyard fowls, 

 but also in many other birds. The form of the bacillus is not 

 specially characteristic except that in old cultures there is a 

 marked tendency to the production of branching threads. In 

 glycerin broth the growth is more delicate, and development 

 takes place at the bottom of the flask as well as on the surface 



'Briscoe and MacNeal: 111. Agr. Exp. Sta. Bull. 149, 1911; Assn. for Tubercu- 

 losis, Transactions, 1912, pp. 460-465. 



^ Journ. Med. Rsch., 191 2, Vol. XXVII, pp. 109-114. 



