686 EXPERIMENT STATION RECORD. [Vol.43 



an examination has been made of possible avenues of transmission of the 

 tubercle bacillus as determined by microscopic examination of culture media 

 inoculated from the material under examination, and by tuberculous infection 

 in guinea pigs inoculated with the same cultures. 



Negative results were obtained with cultures from the dust of rooms in 

 which tuberculous jwitients were living, the mouthpiece of a telephone used 

 in common by the patients at a tuberculosis sanitarium, washings from con- 

 taminated hands and door knobs, and food contaminated, by infected flies. 

 Positive results were obtained from unwashed eating utensils and from pre- 

 viously sterile dishes kissed by tuberculous patients. 



The bacteriological characteristics of tubercle bacilli from different kinds 

 of human tuberculosis, A. S. Griffith (Jour. Path, and Bact., 23 (1920), No. 

 2, pp. 129-152). — This report gives the results of further investigations of the 

 types of tubercle bacilli in human tuberculosis, in continuation of studies some 

 of which have been previously noted (E. S. R., 37, p. 378). The cases examined 

 include tuberculous meningitis, pulmonary tuberculosis, miscellaneous cases, and 

 scrofulodermia. The main objects of the investigation were to determine the 

 relative proportions of the human and bovine types of tubercle bacilli in dif- 

 ferent kinds of human tuberculosis, and the frequency of occurrence and the 

 distribution in the human body of various strains of tubercle bacilli. 



Of the 12 cases of tuberculous meningitis examined, 10 were caused by tlie 

 human type and 2 by the bovine type of tubercle bacilli. The cow's milk which 

 was being supplied to one of the bovine cases proved to contain virulent bovine 

 tubercle bacilli identical with the strain from the meningitis of the child. 



Of the organisms isolated from 17 cases of pulmonary tuberculosis 16 proved 

 to be of the human type and 1 of a variety of tubercle bacilli recently found in 

 various kinds of human tuberculosis and differing in certain respects from both 

 standard bovine and human tubercle bacilli. 



The miscellaneous cases included 3 of bone and joint and S of glandular 

 tuberculosis, and 1 of intramuscular abscess. The organisms isolated from 9 of 

 these cases were of the human type and 3 of the bovine type. Of the latter 

 cases, one is considered of interest as being " the first case in which the bovine 

 type of tubercle bacillus has been demonstrated to be the cause of human 

 tuberculosis which was apparently primary in the bronchial glands." 



Of 52 cases of scrofulodennia from which tubercle bacilli were obtained, 32 

 yielded cultures of the human type and 20 of the bovine type. Of 30 human 

 strains examined culturally 26 showed standard and 4 attenuated virulence. 

 Of the bovine strains 19 cultures from 16 cases showed standard virulence, and 

 6 cultures from 4 cases attenuated virulence. 



The 6 lupus cases examined furnished 3 cultures of the bovine type and 3 of 

 the human type, all of attenuated virulence. In this connection it is pointed out 

 that there is apparently a close relationship between attenuation of tubercle 

 bacilli and nearness of the tuberculosis lesion to the surface of the body. 



The information so far collected on the types of human tuberculosis is sum- 

 marized in tables. Of a total number of 1,068 cases, 803 were of the human, 

 194 bovine, and 5 mixed types of standard virulence. Atypical cases included 21 

 of the human type considered atypical in cultural characteristics, 23 of the 

 human type atypical in virulence, and 22 of the bovine type atypical in viru- 

 lence. The total percentage of bovine infections was 20.7. Classified accord- 

 ing to age the percentages of bovine infection were as follows : From to 5 

 years, 37.55 per cent of 221 cases ; 5 to 10 years, 29.55 per cent of 312 cases ; 

 10 to 16 years, 14.66 per cent of 150 cases; and 16 years and upward, 6.25 per 

 cent of 384 cases. 



