VARIETIES OF TUBERCULOSIS 289 



On glycerin agar and on serum, the growth of tubercle bacilli from 

 birds is more luxuriant, has a moister appearance (Fig. 80, C), and, 

 moreover, takes place at a higher temperature, 43*5 C., than is the case 

 with mammalian tubercle bacilli. Experimental inoculation brings out 

 even more distinct differences. Tubercle bacilli derived from the human 

 subject or from the ox, for example, when injected into fowls, usually 

 fail to produce tuberculosis, whilst those of avian origin very readily do 

 so ; on the other hand, the parrot is susceptible to inoculation with both 

 mammalian types. Fowls are also very susceptible to the disease when 

 fed with portions of the organs containing avian tubercle bacilli, but 

 they can consume enormous quantities of phthisical sputum without 

 becoming tubercular (Strauss, Wurtz, Nocard). The Royal Commission 

 found that rabbits and mice are the only mammals susceptible to 

 inoculation with avian tubercle bacilli, though others may succumb to 

 toxic effects when large doses are used. In the case of a rabbit, 

 intravenous injection results in the formation of greyish-white foci in 

 the spleen, but no true tubercles are formed ; subcutaneous inoculation 

 leads to a peculiar chronic disease in joints, testes, etc., whilst the liver 

 and spleen are free from lesions a result not obtained with mammalian 

 bacilli. 



There is, therefore, abundant evidence that the bacilli derived 

 from the two classes of animals show important differences, and, 

 reasoning from analogy, we might infer that probably the human 

 subject also would be little susceptible to infection from avian 

 tuberculosis. The question remains, are these differences of a 

 permanent character 1 Nocard found that mammalian bacilli of 

 the human type when kept within closed collodion sacs in the 

 peritoneal cavities of fowls over a long period of time, acquired 

 the characters of avian bacilli, but the Royal Commission as the 

 result of similar experiments obtained no evidence of such 

 transformation. It is accordingly not possible at present to give 

 a definite answer to the question. 



3. Tuberculosis in the Fish. Bataillon, Dubard, and Terre 

 cultivated from a tubercle-like disease in a carp, a bacillus 

 which, in staining reaction and microscopic characters, closely 

 agrees with the tubercle bacillus. The lesion with which it 

 was associated was an abundant growth of granulation tissue in 

 which numerous giant-cells were present. It forms, however, 

 luxuriant growth at the room temperature, the growth, being 

 thick and moist like that of avian tubercle bacilli (Fig. 87, c). 

 Growth does not occur at the body temperature, though by 

 gradual acclimatisation a small amount of "growth has been 

 obtained up to 36 C. Furthermore, the organism appears to 

 undergo no multiplication when injected into the tissues of 

 mammals, and attempts to modify this characteristic have so 

 far been unsuccessful. Weber and Taute have cultivated this 

 organism from mud, and also from organs of healthy frogs. It 



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