^24^ 1 SPECIFIC MICRO-ORGANISMS 



■cast which "reacts to o.oooi gram of tuberculin and after treat- 

 irient for 6 months so change the sensitiveness that 0.5 gram maybe 

 injected without reaction. Some cases do remarkably well when 

 treated with tuberculin together with the usual careful hygienic- 

 dietetic treatment^ given in sanitoria, but the value of tuberculin 

 for treatment of the average case, is, perhaps, not yet fully es- 

 tablished.^ In general the tuberculin treatment stimulates the 

 production of a thicker capsule about the healing tuberculous 

 lesion and thus tends to insure against renewed activity of the 

 process at a subsequent time. 



Bacillus Tuberculosis var. Bovinus.— The bovine type of 

 tubercle bacillus is found in the lesions of tuberculous cattle 

 (perlsuckt), frequently in hogs, in a considerable percentage of 

 tuberculous lesions in children, and 'very rarely in the tuberculous 

 lungs of adult human beings. In artificial culture on solid 

 media, the cell is about i/ji long, shorter than that of the human 

 type, and is easily stained. In glycerin broth the length of the 

 cell and the staining is more irregular. On all media the growth 

 is at first much less abundant than that of the human type. 

 Smith has shown that the bovine type produces alkali in glycerin 

 broth during the first two months, whereas the human type 

 tends rather to produce acid. The virulence of the bovine 

 bacillus is greater than that of the human type for all mammals, 

 and it also infects birds. . Intravenous injection of o.ooooi 

 gram of culture in thin emulsion kills rabbits with generalized 

 tuberculosis in about three weeks, while a similar dose of the 

 human variety is without such effect. Subcutaneous injection of 

 rabbits shows a similar difference. Calves are very susceptible 

 to the bovine type, not to the human. 



Tuberculosis of cattle is widely distributed and is very preva- 

 lent in the older European dairy regions. The lesions are most 

 common in the bronchial and retropharjoigeal lymph glands, 

 but they may occur anywhere in the body of the animal. The 



'■ Brown: Jottrn. A. M. A., 1912, Vol. LVIII, pp. 1678-81. 



^BroWn: Amer. Journ. Med. Sciences, 1912, Vol. CXLIV, pp. 469-624. 



