140 SPECIAL BACTERIOLOGY 



them. When dead bacilli are injected intravenously into rabbits, in 

 the animals killed, after some time, small tubercles are found through- 

 out the lungs and liver, formed of round cells, epithelioid cells, giant 

 cells, and dead tubercle bacilli, which cannot be distinguished from 

 the genuine Bacillus tuberculosis. Baumgarten considers that the 

 dead tubercle bacilli produce a tuberculosis similar to that produced 

 by a foreign body (pseudo-tuberculosis). 



Instances in which physicians and veterinary surgeons have con- 

 tracted the disease, in making autopsies of diseased men or animals, 

 are incontestable, although fortunately rare. The virus in such cases 

 gains entrance by some cutaneous wound, causing at first a more or 

 less limited cutaneous tuberculosis, which later may become generalized. 



BOVINE TUBERCULOSIS. 



According to most authorities, tuberculosis of the lungs (see 

 Photomicrograph, Fig. 50) is the most frequent of all the primary 

 forms of this disease in cattle, infection being caused by dried tuber- 

 cular matter inhaled into the lungs. Primary tuberculosis also 

 occurs in the lymph-glands of the head and neck, in the mesenteric 

 glands, the intestines, the liver, the genital organs, and the udder. 

 Bang is inclined to believe that the udder is now and then primarily 

 affected in animals that are in very good condition. Eber reports a 

 case of primary tuberculosis of the penis, and cases involving the 

 vagina and vulva. Finally, generalized infection, due to the dissemi- 

 nation of tubercle bacilli through the blood, occurs in two forms : 

 (1 ) The acute form, when large numbers of bacilli have escaped into 

 the circulation, whereby numerous tubercular foci appear in various 

 organs ; (2) The chronic form, as seen in old cows affected with 

 tuberculosis for many years. A few cases of congenital tuberculosis 

 have been recorded in calves. Johne found tubercle bacilli twice in 

 the organs of embryos. The writer found a case of tubercular 

 meningitis in a calf in California. The mother of this calf was 

 tested with tuberculin and reacted, the post-mortem revealing 

 tubercular lesions, one ovary being affected. 



King mentions a case of a cow giving birth to twin calves. The 

 viscera of both, when submitted to examination, proved tubercular. 

 The cow was not tested with tuberculin, being considered, from 

 apparent symptoms, affected with generalized disease. (Proceeding's 

 of National Veterinary Association^ Leeds, 1898.) 



The bacillus of Koch, according to Nocard, is only in very ex- 



