320 



TYPHOID FEVER. 



question of the morphological relationships of the two organisms has played 

 an important part in the bacteriological investigation of the subject. There 

 has been much controversy as to whether they are varieties of the same species, 

 the result of which is a growing conviction that the two are really distinct. 



The Bacillus Typhosus. Microscopic Appearances. It is 

 sometimes 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 

 just commencing, the spleen, the liver, or a mesenteric gland. 

 The spleen and liver are better than the other tissues named, as 

 in the latter the presence of the B. coli is more frequent. From 

 scrapings of such solid organs dried films may be prepared and 

 stained for a few minutes in the cold by any of the strong stain- 

 ing solutions, e.g. with carbol-thionin-blue, or with Ziehl-Neelsen's 

 carbol-fuchsin diluted with five parts of distilled water. As a 

 rule decolorising is not necessary. For the proper observation 

 of the arrangement of the bacilli in the tissues, paraffin sections 

 should be prepared and stained in carbol-thionin-blue for a few 



minutes, or in LofHer's methy- 

 lene-blue for one or two hours. 

 The bacilli take up the stain 

 somewhat slowly, and as they 

 are also easily decolorised, the 

 aniline-oil method of dehydra- 

 tion maybe used with advantage 

 (vide^. 100). In such prepara- 

 tions the characteristic appear- 

 ance to be looked for is the 

 occurrence of groups of bacilli 

 ^ lying between the cells of the 



FIG. 113. A specially large clump of tissue (Fig. in). The indi- 



typhoid bacilli in a spleen. The individual -IT 



bacilli are only seen at the periphery of the Vldual bacilli are 2 p to 4 //- long, 



mass. (In this spleen enormous numbers of w j t h somewhat OVal ends, and 



typhoid bacilli were shown by cultures to 



be present in a practically pure condition.) -5 P i n thickness. Sometimes 



Paraffin section; stained with carbol-thionin- fil aments 8 JJL to IO //, long may 



blue. X 500. 



be observed, though they are 



less common than in cultures. It is evident that one of the 

 short oval forms may frequently in a section be viewed end- 



