bov 



TYPES OF TUBERCLE BACILLI 291 



bovine or vice versa was possible, and on this point after reviewing the numerous 

 prolonged passage experiments on various species of animals carried out under 

 their direction the Commissioners conclude that " transmutation of bacillary 

 type " is " exceedingly difficult if not impracticable of accomplishment by 

 laboratory procedure." 



[Though it has been considered desirable to introduce thus briefly the conclusions 

 arrived at by the English Commission,] it is altogether beyond the scope of the 

 present work to enter upon a discussion of the arguments which have been brought 

 forward in support of their theses by those who hold that the human tubercle bacillus 

 is identical with the bovine and by those who are of contrary opinion. For these 

 arguments the reader is referred to the publications of the authors whose names 

 are mentioned in the text and to those of other writers on the subject. 



(6) The avian tubercle bacillus. Straus and Gamaleia regard avian tuber- 

 culosis as due to a special organism which, though closely allied to the human 

 bacillus, constitutes a separate species. The view long held by Arloing and 

 others that the human and the avian bacillus are identical has been [held to 

 be] proved by certain experiments of Nocard (vide infra). [It is largely on 

 the results of these latter experiments that] the bacillus of avian tuberculosis 

 has been regarded merely as a strain or race of the human tubercle bacillus. 



Nocard [claims to have] converted an human tubercle bacillus into an avian tubercle 

 bacillus by growing it for a long time in collodion sacs in the peritoneal cavities of 

 fowls. Nocard filled a collodion sac (p. 175) with a thick emulsion of a glycerin- 

 potato culture of a human bacillus. The sac, after remaining at least 4 months in 

 the peritoneal cavity of a fowl, contained a thick mass of bacilli which, when sown 

 on culture media, gave, at first, a scanty growth, and this on sub-culture became 

 more luxuriant and had all the characteristics of a culture of the avian bacillus (a 

 soft, greasy, fatty, easily dissociated and wrinkled layer of growth). These cultures 

 were only slightly virulent for guinea-pigs but highly virulent for rabbits which 

 succumbed to a generalized miliary tuberculosis on inoculation with bacilli from 

 the first passage and when inoculated with bacilli from the second passage the 

 animal died of a tuberculous septicaemia without apparent lesions exactly as though 

 it had been inoculated with an avian bacillus. After three passages of 6-8 months 

 in collodion sacs the human tubercle bacillus killed fowls with symptoms identical 

 with those of the spontaneous disease. 



[A. S. and F. Griffith (working for the English Commission) entirely failed to 

 confirm the results obtained by Nocard. No modification of human or bovine 

 tubercle bacilli into avian, or of avian tubercle bacilli into mammalian, was 

 demonstrated. 



[" With ten mammalian viruses, eight of which were bovine, sixteen collodion 

 capsule experiments on fowls and twenty on pigeons were performed, lasting 55-186 

 days. In certain of the cases cultures, which were obtained from the capsules on 

 removal from the bird's peritoneal cavity, were placed, again in capsules, in the 

 peritoneal cavities of other birds, the total duration of residence being in one series 

 as much as 475 days. In 20 of these experiments cultures were obtained from the 

 capsules and found to be unchanged in character. In the remaining 16 cases the 

 bacilli in the capsules were apparently dead." 



[" Similar experiments were performed with human tubercle bacilli obtained 

 from 12 different sources. These experiments lasted from 59 to 685 days." The 

 results were similar to those obtained with mammalian tubercle bacilli. 



[" With cultures of five avian viruses 25 collodion capsule experiments were 

 performed on guinea-pigs. The duration of residence in individual guinea-pigs 

 ranged up to 253 days and the total periods during which the cultures were in the 

 peritoneal cavities of series of guinea-pigs varied up to 424 days." In two instances 

 the bacilli in the capsules were dead : " from all the other capsules cultures were 

 obtained and the bacilli were found to be unchanged " in cultural characteristics 

 and virulence. ] 



Lydia Rabinowitsch isolated thirty-four strains of tubercle bacilli from birds. 

 Two of these, isolated from birds of prey, had all the characteristics of the human 

 bacillus. Rabinowitsch concluded from this investigation that the human and 



