Tuberculosis of Mammals and Fowls. 617 



persistent investigation and study of Koch's tubercle bacillus 

 has at least cast doubt upon the supposed relationship of 

 mammalian and avian tuberculosis. It has, for instance, been 

 found that the bacilli causing these two morbid processes 

 possess marked cultural differences, that the diseased organs 

 of tuberculous mammals, as well as the cultures of bacilli 

 obtained from them (with rare exceptions) possess only slight 

 pathogenicity for fowls, and that, on the other hand, the bacilli 

 of avian tuberculosis have a different effect upon mammals than 

 the bacilli of mammalian tuberculosis. 



On account of these facts some authors (Rivolta, Maffucci, 

 Strauss & Gamaleia, more recently also Weber & Bofinger) 

 regard these two forms of bacilli as distinct species and con- 

 sequently also look upon mammalian and avian tuberculosis 

 as two etiologically distinct diseases. On the other hand there 

 is weighty evidence pointing to a close relationship between 

 these two forms of bacilli. 



In this connection the cultural differences between the two 

 organisms are of slight significance for the reason that cultures of 

 bacilli from the lesions of tuberculous fowls frequently resemble those 

 obtained from mammals. Thus Weber & Bofinger occasionally obtained 

 dry crumpled cultures from fowls, a culture that had been kept up 

 for years could not be distinguished from cultures of human bacilli, 

 but after a single passage through a fowl or a mouse this charac- 

 teristic was lost. And again 0. Bang has observed many strains of 

 avian bacilli, grown on glycerin potato medium, to produce dry, uneven 

 masses, while one bovine strain observed by this author, when cultivated 

 on glycerin serum resembled an avian culture in appearance. In 

 addition to these observations it is known that some avian strains 

 when cultivated on bouillon can hardly be differentiated from bovine 

 varieties. Among 95 strains obtained from 70 different birds Rabino- 

 witsch found occasional strains that exhibited characteristics of growth, 

 on solid as well as on liquid media, very similar to those of mammalian 

 bacilli. Three of these strains, however, belonged undoubtedly to that 

 group (pathogenic for guinea pigs, nonpathogenic for fowls) . Finally, 

 it is possible, by means of special methods, to obliterate these differences. 

 Thus Pischel obtained a material by cultivating human tubercle bacilli 

 on egg medium and on boracic-acid-glycerin-agar that would produce 

 moist smeary cultures on the ordinary media. Nocard cultivated human 

 tubercle bacilli in collodion capsules filled with bouillon which he 

 imbedded in the abdominal cavity of fowls. After several months these 

 capsules were removed, the bacilli transferred to solid culture media 

 and cultures produced that resembled avian cultures in every respect. 



■ The marked differences in the pathogenicity of the two forms of 

 bacilli are of vastly greater importance. It is, for instance, impossible 

 to infect any of the various species of fowls by feeding with organs 

 of tuberculous mammals. Straus and Wuertz have fed chickens for 

 months with tuberculous organs and sputum of tuberculous persons, 

 and although some of them received as much as 58 kg. of such material 

 they remained healthy. Similarly negative results were obtained by 

 Bsser, Peroneito, Nocard and others. Since, however, tuberculosis 

 among fowls frequently occurred under circumstances pointing to in- 



