BACILLUS TYPHI ABDOMINALIS. 249 



liver, but not so numerous in the kidneys. They 

 are not diffusely distributed in these organs, but 

 always occur in the form of small isolated deposits. 

 This renders the microscopical investigation especially 

 difficult ; it is often only after the examination of a large 

 number of sections that one or a few of these deposits 

 are found. The masses occur in the form of groups with 

 irregular outlines lying usually in the capillaries or 

 smallest blood vessels, these groups being resolved at 

 their margins into individual bacilli (see fig. 69). 



The latter appear as rods 23 P. in length, and Morphological 

 about three times less in breadth. Their ends are 

 distinctly rounded off. In many cases undoubted spores 

 are found in the bacilli, presenting the appearance of 

 round unstained portions occupying the whole breadth 

 of the rod. Aniline dyes are slowly taken up, but quite 

 sufficiently when the staining process is continued for 

 a considerable time ; the best stains are gentian violet, 

 Bismark brown, and especially alkaline methylene blue. 

 With Gram's method the typhoid bacilli are very readily 

 and completely decolourised. 



Gaffky was the first to cultivate these bacilli on suit- 

 able soil from the organs of patients who had died from 

 typhoid fever. Former attempts by other investigators 

 did not lead to a pure culture of the typhoid bacilli. 

 Gaffky succeeded in 13 cases in obtaining pure cultiva- 

 tions of the bacilli, by planting on nutrient jelly minute 

 portions of tissue taken with all precautions from the 

 interior of the spleen. These cultivation experiments 

 showed that even in the cases where on microscopical 

 examination it was only with difficulty and in a small 

 proportion of the sections that bacilli could be demon- 

 strated, every minutest portion of the juice of the 

 organ gave rise to several colonies of bacilli, so that 

 it was evident that the best idea of the number of 

 bacilli present, and of their distribution, could be 

 obtained by the cultivation method. Cultivations of the 

 typhoid bacilli have since been repeatedly made ; they 

 are invariably successful from the organs of fresh typhoid 

 bodies. Pfeiffer has recently succeeded in isolating 



