XL] BACILLUS : PATHOGENIC FORMS. 123 



then f.aseating in the centre ; enlargement and subsequent 

 caeeation of the bronchial glands. 



Owing to the fact that the tubercle-bacilli require for their growth high 

 temperatures (38 40 C.), it is evident that, unlike some other pathogenic 

 organisms, they do not thrive in the outside world in temperate climates. 



Inoculation with the pure bacilli into the anterior chamber 

 of the eye of rabbits and guinea-pigs produces the character- 

 istic tuberculosis described by Cohnheim and Salomonsen. 

 After an incubation of from two to three weeks there appears 

 on the iris a crop of minute grey tubercles enlarging and 

 undergoing caseous degeneration. Later on general tubercu- 

 ]osis of the eyeball and other organs follows. So that Cohn- 

 heim's assertion, that only tuberculous matter implanted into 

 the anterior chamber of the eye can produce this outbreak of 

 a crop of tubercles on the iris, is, by Koch's observations, 

 strengthened in the highest degree ; the tubercle-bacilli present 

 in, and characteristic of, true tubercles are thus manifestly 

 connected with the real cause of the morbid growth. A large 

 number of pathologists have, since the publication of Koch's 

 paper, devoted themselves to various parts of this question of 

 the relationship of the tubercle-bacilli to the tuberculous 

 process, and have, with few exceptions, verified Koch's obser- 

 vations. The chief opposition, leaving out of account those 

 who, either from imperfect technical skill in the manipulation 

 and staining of the bacilli, or by reason of the inadequate 

 number of their observations, have denied Koch's statements, 

 comes mainly from observers who, like Toussaint, Klebs, and 

 Schuller, maintain that tuberculosis is due to a micro-organism 

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

 teliits and others, do not admit that human and bovine tuber- 

 culosis are the same, and are, therefore, not interchangeable, 

 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 examina- 

 tions 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 examination for bacilli of 

 the sputum of patients suspected of tuberculosis. 



