CHAPTER XIV. 



TYPHOID FEVER BACILLI ALLIED TO THE 

 TYPHOID BACILLUS. 



OTHER NAMES. ENTEEIC FEVER : GASTRIC FEVER. GERMAN, 



TYPHUS ABDOMINALIS : ABDOMINALTYPHUS : UNTERLEIBS- 

 TYPHUS. FRENCH, LA FIEVRE TYPHOIDE. 



Introductory. The organism now known as the bacillus 

 typhosus was first described in 1880-1 by Eberth, who observed 

 its microscopic appearances in the intestinal ulcers and in the 

 spleen in cases of typhoid fever. It was first isolated (from 

 the spleen) in 1884 by Gaffky, and its cultural characters were 

 then investigated. In 1885 Escherich observed a bacillus, now 

 known as the bacillus coli communis, which occurs in the normal 

 intestine and which both microscopically and culturally closely 

 resembles the typhoid bacillus. Ordinarily the b. coli is no 

 doubt a harmless saprophyte, but under experimental conditions 

 in animals and also naturally in man it may manifest pathogenic 

 properties. Investigation has shown that these two bacilli 

 belong to a widespread group of organisms isolated from various 

 disease conditions, which all bear close resemblances to one 

 another and whose differentiation is often a matter of consider- 

 able difficulty. Other members, of this group are the para- 

 typhoid bacillus, the organism of bacillary dysentery, the b. 

 enteritidis of Gaertner, the psittacosis bacillus, and the bacillus 

 of hog cholera. 



Bacillus Typhosus. Microscopic Appearances. It is some- 

 times difficult to find the typhoid bacilli in the organs of a 

 typhoid patient. Numerous sections of different parts of a 

 spleen, for example, may be examined before a characteristic 

 group is found. The best tissues for examination are a Peyer's 

 patch where ulceration has not yet commenced or where it is 



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