624 Tuberculosis. 



cutaneous injection of bovine bacilli. In the investigations of the 

 Imperial Board of Health, 1 out of 11 strains of bovine bacilli had 

 a similar mild action (injected intravenously, however, it was quite 

 virulent), while Dammann & Muessemeier found the injection of 5 eg. 

 of a culture of bacilli into a calf absolutely ineffective. According 

 to the report of the British Commission the subcutaneous injection 

 of bovine bacilli occasionally produces only local changes, which, when 

 they become more general (as may sometimes occur) are limited to 

 occasional, small foci in internal organs usually in an arrested stage 

 of development. Between the two extremes of rapidly progressive 

 generalized tuberculosis and of well marked regressive forms, every 

 possible intermediate form may be observed. 



The feeding of bovine virus frequently fails to result in severe 

 disease. Thus Nocard failed to get positive results in four attempts, 

 Hutyra failed to produce serious infection of calves six months of 

 age by feeding cultures of bacilli, and the British Commission observed 

 tuberculous changes only in the immediately adjacent regions of the 

 intestinal tract following alimentary administration of milk containing 

 tubercle bacilli. Schweinitz, Schroeder, Nocard and Eber have obtained 

 bacilli from cattle that were only slightly virulent for calves, while 

 Preisz produced in one calf tuberculous changes in one peribronchial 

 lymph gland only and failed to cause any observable changes whatever 

 in a second calf, both of which received intravenous injections of 

 a mixture of six different strains of bovine bacilli (see also experiments 

 of Kossel, Weber & Heuss, p. 508). 



Pathogenic Action of the Two Types of Tubercle BaciUi on 

 Other Animals. More recent investigations have, above all, confirmed 

 the observations of the past that the human type of tubercle bacillus 

 is decidedly less virulent for rabbits and guinea pigs than the bovine 

 type, and that it is frequently impossible to infect rabbits at all with 

 bacilli of the former type (Smith, Ravenel, Kossel, Weber & Heuss). 

 Similar observations have been made also with regard to sheep and 

 goats (Dinwiddle, Ravenel, Beck) ; Karlinski, hoM'ever, successfully in- 

 fected pregnant goats with intravenous and intramammary injections, 

 and kids by alimentary administration of human bacilli while Dammann 

 & Muessemeier observed slight tuberculosis of the lymph glands of 

 lambs following feeding of human material and in one case fatal tuber- 

 culosis followed within 44 days after alimentary administration of 

 0.1 gm. of bovine culture. 



In regard to the susceptibility of other species of animals the 

 results of experiments have varied. While, for instance, according 

 to Dinwiddle and Gratia the two forms of bacilli possess much the 

 same action toward horses, swine, dogs and cats, Ravenel noted the 

 same differences that are mentioned above. Aside from the fact that 

 bovine bacilli are always present in the organs of tuberculous swine 

 the virulence of this type of bacilli is abundantly demonstrated by 

 the rapid and certain infection of large herds of swine that have 

 been fed on skim milk. On the other hand Dean & Todd infected 

 swine by feeding tuberculous pas from man and Dammann saw a 

 pig die within 42 days after subcutaneous infection with a culture of 

 human tubercle bacilli. In the feeding experiments of Kossel, Weber 

 & Heuss, the result of infection was always a chronic general tuber- 

 culosis of slow evolution. Th. Smith and Ravenel produced cultures 

 of typical bovine bacilli from swine, the same from one horse and 

 an intermediate form from a second horse. 



