Bovine Tuberculosis 343 



shape. The human bacilli, on the other hand, are prone to 

 take an elongate form under artificial cultivation. 



Staining. The bovine bacillus usually stains homogen- 

 eously; the human bacillus commonly shows the so-called 

 "beaded appearance," and is more apt to contain rounded, 

 deeply staining bodies suggestive of spores, at or near the 

 ends. 



Vegetation. The human bacillus grows upon dog's 

 serum much more luxuriantly and rapidly than the bovine 

 bacillus. 



Pathogenesis. (a) Guinea-pigs. The bovine bacilli are 

 more virulent than those of human tuberculosis, intraperi- 

 toneal inoculation of the former producing death in adult 

 animals in from seven to sixteen days ; of the latter, in from 

 ten to thirty-eight days. Subcutaneous inoculation of the 

 bovine bacillus causes death in less than fifty days; of the 

 human bacillus, in from fifty to one hundred days. 



(b) Rabbits. Rabbits inoculated into the ear vein with 

 the bovine bacillus die in from seventeen to twenty-one days. 

 Those receiving human bacilli sometimes live several months. 



(c) Cattle. Cows and heifers receiving intrapleural 

 and intra-abdominal injections of the human bacilli usually 

 gain in weight and show no symptoms. When examined 

 post mortem, circumscribed chronic lesions were found. 

 Those inoculated with the bovine bacillus lose weight, suffer 

 from constitutional symptoms, and show extensive lesions 

 at the necropsy. Two- thirds of the cattle inoculated experi- 

 mentally with the bovine bacillus die. 



Lesions. In general the lesions produced by the bovine 

 bacillus were rapid, extensive, and necrotic. Many bacilli 

 are present. Those produced by the human bacillus are 

 more apt to be productive, chronic, and unaccompanied by 

 large numbers of bacilli. The bacilli of human tuberculosis 

 produce lesions with many giant-cells; those of bovine 

 tuberculosis, lesions with rapid coagulation-necrosis. The 

 lesions resulting from the intravenous injection of human 

 bacilli into rabbits resembled those observed by Prudden and 

 Hodenpyl* after the intravenous injection of boiled, washed 

 tubercle bacilli. 



From these data it is evident that the bovine bacillus 

 is by far the more virulent and dangerous organism. While 

 *"New York Med. Jour.," June 6-20, 1891. 



