XL] BACILLUS ; PATHOGENIC FORMS. 125 



artificially tuberculised are quite correct ; (4) That material 

 other than tuberculous does not produce tuberculosis, that is 

 to say, that the cases of artificial tuberculosis in guinea-pigs 

 observed by Wilson Fox and Burdon Sanderson, and in the 

 older experiments of Cohnheim and Fraenkel, viz. those in 

 which chronic inflammation and caseation (i.e. artificial 

 tuberculosis) was thought to have been induced by other than 

 tuberculous matter, e.g. by non-tuberculous caseous matter, 

 setons, indifferent substances like bits of gutta-percha inserted 

 into the peritoneal cavity, &c., were really due to accidental 

 contamination with tuberculous material. 



According to my own experience extending over a very 

 large number of cases of human miliary tuberculosis and 

 tuberculosis of cattle, I cannot for a moment accept the 

 statement that the bacilli found in the two affections are 

 identical ; for I find that in the two diseases their morpho- 

 logical characters and distribution are very different. The 

 bacilli of human tuberculosis are conspicuously larger than 

 those of the tuberculosis of cattle, and in many instances 

 more regularly granular. As is seen in Figs. 83-85, those 

 of human sputum are nearly half, or at least one-third, as 

 large again as those of the caseous masses from the lungs of 

 cattle. 



The bacilli in the tuberculous deposits of cattle are always 

 contained in the cells ; the larger the cell the more numerous 

 the bacilli. This fact comes out very strikingly in thin and 

 well-stained sections. Around many of the smaller and larger 

 clumps of bacilli the cell-outline is still recognisable, and when 

 the cell disintegrates, as it does sooner or later, the bacilli 

 become free in groups ; in this respect there exists a remarkable 

 similarity between leprosy and bovine tuberculosis. But in 

 the human tubercles the bacilli are always scattered between 

 the cells. 



I cannot agree with Koch, Watson Cheyne, and others, who 

 maintain that each tubercle owes its origin to the immigration 

 of the bacilli, for there is no difficulty in ascertaining that in 

 human tuberculosis, in tuberculosis of cattle, and in artificially 

 induced tuberculosis of guinea-pigs and rabbits, there are met 

 with tubercles in various stages young and adult in which 

 no trace of a bacillus is to be found ; whereas in the same 

 section cheesy tubercles may be present containing numbers of 

 tubercle-bacilli. 



Schuchardt and Krause l have found tubercle-bacilli, though 



1 Fortschrilte d. Mcd. 9, 18S3. 



