886 EXPERIMENT STATION RECORD. 



tubercle bacilli. Cultures of slight virulence for rabbits, with the cultural 

 characters of [certain] human tubercle bacilli, [were] obtained from a chim- 

 panzee and from a rhesus monkey, also the subjects of casual tuberculosis. 

 The chimpanzee acquired the disease by ingestion, the post-mortem examina- 

 tion showing several ulcers in the small intestine and enlargement and caseation 

 of the mesenteric glands. The immediate cause of death was acute miliary 

 tuberculosis of the lungs. The rhesus monkey had chronic pulmonary tubercu- 

 losis and slight disseminated disease. From the mesenteric gland of a cat 

 affected with casual tuberculosis a culture was isolated which grew with diffi- 

 culty on the various differential media, resembling a bovine tubercle bacillus. 

 It was fully virulent for rabbits and guinea pigs, and not virulent for the fowl." 



From the investigations on avian tubercle bacilli obtained from birds and 

 swine no constant or important differences were observed either in the cul- 

 tural characters or in the pathogenic properties of the organisms isolated and 

 examined. 



From the modification experiments which were conducted with birds and 

 various mammals it is concluded that little support can be given " to the sur- 

 mise that modification of the recognized types of bacilli can be experimentally 

 induced by passage through animals. In the majority of the numerous exiieri- 

 ments in which cultures of mammalian and of avian tubercle bacilli have been 

 obtained after residence of the bacilli of experiment in a single animal or 

 after passage through a series of animals no change whatever has occurred 

 either in cultural characters or virulence. It has happened in a few instances 

 that cultures differing widely from those inoculated have been obtained from 

 one or other animals, but where these occurrences are not clearly referable 

 to complication by natural tuberculosis they are so exceptional that the pre- 

 sumption is against modification of the bacilli having been effected." 



The results of the work with the artificially mixed cultures show "that if a 

 calf is inoculated subcutaneously with a mixture of a slightly virulent culture 

 and a virulent culture, it is possible to recover from the lesions produced cul- 

 tures in which the virulent element can alone be demonstrated, even though in 

 the original mixture the slightly virulent bacilli were in preponderating num- 

 bers. This elimination is demonstrable when, as in this case, there is a wide 

 difference between the cultural characters of the two cultures. A similar 

 result can be obtained, though less quickly, by means of the subcutaneous 

 inoculation of rabbits." 



Comparative histological and bacteriolog'ical investigations, A. Eastwood 

 (Roy. CoM,. Tuherculosis, Final Rpt., II, App., 5 (1911), pp. SJfJf, pis. 16). — 

 This is the continuation and final report of the work reported in the appendix 

 to the second interim report of the Royal (Commission on Tuberculosis (E. S. R., 

 19, p. 984). 



When comparing tubercle bacilli of known human origin with those obtained 

 from other mammalia having spontaneous disease, it was noted that in every 

 case the bacilli from other than human origin were identical culturally, micro- 

 scopically, and in their effects upon the tissue of the experimental animals with 

 the bacilli obtained from certain cases of tuberculosis in man. 



With reference to the anatomical origin of the human viruses investigated, 

 attention is called to the fact that in every part of the human body tubercle 

 bacilli were found which were culturally and in their histological effects identi- 

 cal in every respect to the tubercle bacilli usually found in the bodies of tuber- 

 culous swine and cattle. On the other hand, many bacteria were noted which 

 grew with more luxuriance and produced much less tissue destruction in the 

 organs of certain exijerimental animals than those bacilli which came from 

 tuberculous cattle and swine. 



