OTHER ACID-FAST BACILLI 283 



toxic effects when large doses are used. In the case of, the 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. 82, 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 frpgs. It 

 is thus probably to be regarded as a saprophyte which is only 

 occasionally associated with disease in the fish. 



According to the results of different experimenters, it is possible to 

 modify human tubercle bacilli by allowing them to sojourn in the tissues 

 of cold-blooded animals, e.g., the frog, blind- worm, etc., so that they 

 flourish at lower temperatures. These results have, however, been 

 recently called in question, as it has been stated the organisms obtained 

 were not modified tubercle bacilli, but other acid-fast bacilli which may 

 be found in the tissues of normal cold-blooded animals. This question 

 must accordingly be considered still an open one. 



Other Acid-fast Bacilli. — Within recent years a number of 

 bacilli presenting the same staining reaction as the tubercle 



