TYPHOID FEVER. 



METHODS OF THE DIAGNOSIS OF THE TYPHOID BACILLUS. 



The Differences between the B. typhosus and the 

 B. coli: 



B. Coli. 

 Flagella fewer and shorter. 



Growth faster and more vigorous. 



. 



Growth on potatoes, a brow 



pellicle. 

 Well-marked acid production. 



Fermentation pronounced. 



Milk coagulated. 



Abundant gas formation round 



colonies. 

 Well-marked indol production (in 



some varieties none Klein). 

 Bacilli remain actively motile. 



B. Typhosus. 



Flagella more numerous, longer, 



and more wavy. 



In artificial media growth gener- 

 ally slower and not so vigorous. 

 Growth on fresh acid potatoes, a 



nearly transparent film. 

 Very slight acid production 



in ordinary media, followed 



sometimes by production of 



alkali. 

 Fermentation of lactose very 



slight if any. 

 Milk not coagulated. 

 Gelatine shake cultures no gas 



formation. 

 Production of indol in ordinary 



bouillon nil. 

 Widal's reaction. Bacilli become 



clumped together and motion- 

 less in the serum of a typhoid 



patient. (A similar reaction is 



given by the blood serum of an 



animal immunised against the 



typhoid bacillus). 



Pathological Changes in Typhoid Fever. As these 

 are sufficiently described in ordinary pathological text- 

 books, we can confine our attention solely to their bacterio- 

 logical aspects. It is generally recognised that the inflam- 

 mation and ulceration in the Peyer's patches and solitary 

 glands of the intestine are the central features of the disease. In 

 the early stage of this disease there is to be observed with the 

 naked eye a swollen and slightly pinkish appearance of the 

 patches and lymphoid tissue of the intestine. From the 

 study of the histological appearances in such patches and 

 in the lymphoid tissue, it is seen that there has been pro- 

 duced an acute inflammatory condition, attended with 



