i68 MICRO-ORGANISMS AND DISEASE. [CHAP. 



is a micrococcus and not a bacillus, or who, like Schot- 

 telius and others, do not admit that human and bovine 

 tuberculosis are the same, and are, therefore, not inter- 

 changeable, which they ought to be if in both the same 

 bacillus occurs, and if this bacillus is the vera causa morbi. 

 But there can be no doubt that a vast number of competent 

 observers have fully verified Koch's dictum, that the 

 tubercle-bacilli are specific and different from other bacilli, 

 except those of leprosy, as regards their chemical nature 

 (compare their behaviour to nitric acid) ; and that wherever 

 they are present in the sputum we have to deal with real 

 tuberculosis, wherever after repeated examinations they are 

 found to be absent there is no tuberculosis. This has by 

 this time, although not much more than a couple of years 

 has elapsed since Koch's first publication, become in 

 the hands of all competent workers a matter of daily 

 practical application, especially as regards the examina- 

 tion for bacilli of the sputum of patients suspected of 

 tuberculosis. 



The other equally important part of Koch's discovery, 

 namely, the artificial cultivation of the tubercle-bacilli and 

 the production with them of tuberculosis, has also been 

 verified by Weichselbaum. 1 Weichselbaum also ascertained 2 

 that in acute miliary tuberculosis of man the blood contains 

 the bacilli. 



An important series of observations was published by 

 Mr. Watson Cheyne in the Practitioner for April 1883, 

 in which he proved, (i) That the organs of rabbits 

 and guinea-pigs suffering from the tuberculosis induced 

 by Toussaint's cultivations from the blood of tuberculous 

 animals, which cultivations Toussaint considered to be 

 those of micrococci, turned out, on careful microscopic 

 1 Wiener med. Blatter, 1883. 2 Ibid. 10, 1884. 



