622 Tuberculosis. 



demonstrated were all children under eight years of age, three of them having 

 generalized miliary tuberculosis. Among 12 cases in children under 10 years of 

 age five were due to infection by the bacillus of the human type alone, six to 

 infection by bacilli of the bovine type alone and one to infection by bacilli of 

 both tjT)es. (Up to April, 1907, pure cultures of the human type of bacillus were 

 obtained from 117 out of 138 cases of human tuberculosis [Steffenhagen]). The 

 bacillus of the bovine type was found exclusively in 11 tuberculous cattle, in seven 

 tuberculous swine and in one tuberculous sheep. 



From the above noted results the authors draw the conclusion 

 that in those rare cases where tuberculous human beings can discharge 

 bovine bacilli they may be the means of infecting cattle and that, on 

 the other hand, infection of human beings is caused primarily from 

 man to man, but that the possiliility must be admitted that human 

 beings may be infected with meat or milk from tuberculous cattle 

 (and swine). TFiey further admit, or assume, that tuberculous cattle 

 are always infected with bacilli of the bovine type only and that swine 

 and other domestic animals Avhile generally infected with this type may 

 occasionally also be infected with bacilli of the human type. 



The results of the experiments above referred to were augmented 

 by Oehlecker who obtained 45 pure cultures of human bacilli and 



5 pure cultures of bovine bacilli from 50 different surgical cases of 

 tuberculosis. 



The British Commission (Foster, "Woodhead, Martin, McFadyean 



6 Boyce) arrived at similar results in so far as they found pure 

 cultures of tubercle bacilli obtained from human beings to possess 

 different degrees of virulence while in pure cultures obtained from 

 cattle this variation was not as pronounced. 



Pure cultures obtained from 60 cases of human tuberculosis could 

 be classified into two general groups. Group I included 14 strains 

 which agreed in that they did not grow readily on artificial culture 

 media (dysgonic strains) and that all of them produced generalized 

 and progressive (though not always equally pronounced) tuberculosis 

 in cattle as well as in other animals. Group II included 40 strains 

 that were characterized by their ready growth on artificial media 

 (eugonic strains) and by the production, in cattle, of local disease 

 only or, at most, isolated tuberculous foci of a retrogressive character 

 and by not producing generalized tuberculosis even when administered 

 in large amounts, nor being very virulent even for rabbits. Finally, 

 this commission recognized six strains which, on account of the variable 

 character of their virulence, could not be classed in either of these 

 groups. 



In 30 instances cultures which agreed in their cultural and patho- 

 genic characteristics wuth the strains of Group I were found in cattle. 

 All of these had a decided pathogenic action not only for cattle, but 

 also for other mammals, including monkeys. 



Among 60 cases of human tuberculosis there were 28 in which the clinical 

 symptoms indicated that infection occurred through the intestinal tract and of 

 these the bacillus of the Group I type was found in 13; of 9 cases of tuberculosis 

 of the cervical glands 3 belonged to this group and of 19 cases of tuberculosis of 

 the peritoneum 10 were caused by the bacillus of Group I. 



In view of the existence of intermediary forms as well as the 

 variable virulence even of strains classified in each group the com- 

 mission has not found it advisable to recognize two distinct types of 

 bacilli. Nevertheless Cobbett called attention to the fact that it is 

 possible, even with only limited experience, to recognize in advance 



