TUBERCULOSIS. 433 



have about the same virulence for cattle as had the bacilli from 

 bovine animals affected by the disease. 



Kossel, in a preliminary report, stated that the German commission 

 had tested 7 cultures of tuberculosis from cattle and hogs — 4 from 

 cattle and 3 from hogs. Two proved acutely fatal in cattle after 

 eight to nine weeks ; 4 likewise produced a generalized tuberculosis, 

 but which certainly had a more chronic course, while 1 of the cul- 

 tures caused only an infiltration at the point of inoculation, with 

 some caseous foci in the adjoining prescapular gland and in one of 

 the mediastinal glands, and there was lacking the spreading of the 

 tuberculosis over the entire body which they were accustomed to see 

 after the injection of cultures of bovine tuberculosis. " Hence," says 

 Kossel, " among bovine tuberculosis bacilli there can also occur differ- 

 ences with regard to the virulence." 



The German commission also tested 39 different fre.-lily made cul- 

 tures from tuberculous disease in man. Nineteen did not produce the 

 slightest symptoms in cattle ; with 9 others the cattle exhibited after 

 four months very minute foci in the prescapular glands, which were 

 mostly encapsuled and showed no inclination to progress; with 7 

 other cases there was somewhat more marked disease of the prescap- 

 ular glands, but it did not go so far as a material spreading of the 

 process to the adjoining glands. There were 4 cultures, however, 

 which were more virulent and caused generalized tuberculosis in the 

 cattle inoculated with them. 



It would appear, therefore, that hereafter everyone must admit 

 that it is impossible always to tell the source of a culture of the 

 tubercle bacillus by its effect when it is inoculated upon cattle. One 

 of the bovine cultures failed to produce generalized tuberculosis in 

 cattle, and some of the human cultures did produce it in such ani- 

 mals. Moreover, while some of the human cultures caused no disease 

 at all, others led to the development of minute foci in the prescapular 

 glands, and still others to somewhat more marked disease of the 

 glands. There were, consequently, four degrees of virulence noted 

 in these 39 cultures of bacilli from human sources and three degrees 

 of virulence in the 7 cultures from animal. 



Now, if we accept the views of Koch as to the specific difference 

 between human and bovine tubercle bacilli, and that the human bacilli 

 produce only localized lesions in cattle, while bovine bacilli produce 

 generalized lesions in them, must we not conclude that the one non- 

 virulent bovine culture was in reality of human origin, and that 

 the animal from which it was obtained had been infected from 

 man ? This is a logical deduction, but reverses the dictum laid down 

 at London that human tuberculosis is not transmissible to cattle. 

 Again, how are w^e to explain the human cultures of medium viru- 

 lence? Are they human bacilli which, for some unknown reason, are 



54793°— 23 28 



