BACILLUS TYPHOSUS. 299 



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 

 Loffler's methylene-blue for one to two hours. The bacilli 

 take up the stain somewhat slowly, and as they are also 

 easily decolorised, the aniline oil method of dehydration 



FIG. 76. A specially large clump of typhoid bacilli in a spleen. The 

 individual bacilli are only seen at the periphery of the mass. (In this 

 spleen, enormous numbers of typhoid bacilli were shown by cultures to be 

 present in a practically pure condition. ) 



Paraffin section ; stained with carbol-thionin-blue. x 500. 



may be used with advantage (vide page 96). In such 

 preparations the characteristic appearance to be looked for 

 is the occurrence of groups of bacilli lying between the cells 

 of the tissue (Fig. 76). The individual bacilli are 2 //, to 4 p 

 long, with somewhat oval ends, and .5 //, in thickness. Some- 

 times filaments 8 ^ to 10 p long may be observed, though 



