No 6. DEPARTMENT OF AGRICULTURE. 295 



sei'um. On gljcorin agar, glycerin bouillon and potato with gljcerin, 

 the baeilli fi-oni the two sources approach eadi other in appearance 

 and morphology much more closely. 



The human cultures isolated have without exception grown more 

 luxuriantly than the bovine cuUures, though in at least two instances 

 (cultures U and BB) the first growth was very long in appearing. 

 This was due no doubt to their feeble virulence and consequent slow 

 production of lesions in the tissues of guinea-pigs. A saprophytic 

 life once established, thej'^ grew vigorously. 



The bovine cultures are apt to grow as discrete colonies in the first 

 culture, and for several generations are likely to grow as an exceed- 

 ingly thin layer over a part of the medium, resembling closely ground 

 glass. 



The human bacillus can usually be induced to grow on glycerin 

 agar in sub-cultures made from the original growth on blood-serum. 

 All attempts to obtain a like result with the bovine organism have 

 failed. 



Three of the bovine cultures examined have been isolated from 

 milk. Two of these, L and Q, have shown throughout the characters 

 of the type described as ''bovine," while T approaches the human 

 bacillus in morphology, being long and slender. It is, however, more 

 virulent than any human culture tested. 



Among the human cultures, only one (M) has been isolated from 

 sputum. Through the kindness of Dr. Alfred Hand, Pathologist of 

 the Children's Hospital, to whom we beg to make grateful acknowl- 

 edgments, we have been able to obtain cultures from three cases of 

 tuberculosis in young children in which the intestine was involved. 

 One of these, from which culture BB was isolated, was considered 

 by Dr. Hand to be "more clearly than any other he had ever seen, 

 of intestinal origin," and was therefore studied with peculiar inter- 

 est. Its pathogenicity has not yet been determined, but the course 

 of the disease in the guinea-pigs inoculated to obtain the culture indi- 

 cated a very feeble virulence, one living sixty-six and another ninety- 

 six days. The bacilli, even in the first generation, are unusually long 

 and thick. They stain deeply with cabol-fuchsin, but are beaded in 

 a striking manner, the brightly stained portions being quite regu- 

 larly disposed along the rod. They are most unlike what we have 

 described as the bovine type in every way. 



Cultures U and W, also from children with intestinal lesions, cor- 

 respond to the human type in every particular, both as regards mor- 

 phology and virulence. 



COMPARISON OF CULTURES H (BOVINE) AND K (HUMAN). 



IIistor.y of Cultures. — Culture H (bovine) was isolated from the 

 mesenteric gland of a Jersey grade cow about seven years old, which 

 had been slaughtered for beef, but found to be extensively diseased 



