BACILLUS TUBERCULOSIS 



347 



rat, mouse, rabbit, or guinea-pig, fowl or ostrich, if in sucli 

 a nodule the bacilli characteristic of tubercle can be 

 demonstrated, tliat nodule is tubercle, and the disease tuber- 

 culosis. The discovery by Koch oi this fundamental fact 

 marks one of the most brilliant and most practical dis- 

 coveries of modern medical science ; the diagnosis of tubercle, 



i- IG. 137. — Th;-:ee TL^T-TLi e C'.LTr.'ATj'"':;s I IF TuLiuRCLE Eacilli o:; Gl^'CERIN 

 Agak a.fte:: ^e'.ekal Weeks. 



once 50 difticult to make with certaintv, is now, by 

 means of the demonstration of the presence of the tubercle 

 bacilli, one of the easiest and at the same time one of the 

 most important helps in the formation of a correct diagnosis 

 in many otherwise doubtful cases. Koch ftirther proved 

 that not only are these particular bacilli present in all and 

 every tubercle of man and brutes, but he also showed that 



