364 MICRO-ORGANIS^IS AND DISEASE [chap. 



a thin film on a cover-glass, drying and heating then stain- 

 ing after Ehrlich's method of staining for tubercle bacilli 

 (in carbol fuchsin for twenty to thirty minutes at 35° C, 

 then washed in water, then for a few seconds in 33 per 

 cent, nitric acid, washed again in water, dried, and mounted) 

 show the leprosy cells, some small, some very big, all 

 crowded with the stiff, thin, and relatively long bacilli 

 lepra;. Many cells are in a state of disintegration, or 

 broken down into granular debris and in accordance with 

 this numerous bacilli are found free, isolated, or in groups. 

 The large and middle-sized cells are particularly interesting, 

 since their substance is almost entirely occupied with the 

 bacilli arranged in bundles, which bundles often lie towards 



Fig. 144. — From an artificial Culture of Bacillus of Lefrosv. 

 (.After Nelsser.) 



one another under sharp angles, and hereby produce a 

 very striking effect. Sections through a leprous tubercle 

 stained in the above manner (in carbol fuchsin passed 

 through 33 per cent, nitric acid, washed in water, then 

 counter-stained in methyl blue anilin water for fifteen to 

 thirty minutes) show the nuclei of the tissue blue, the cells 

 forming the leprous nodule red, owing to the fact that their 

 substance is crowded with the (red) leprosy bacilli ; in such 

 sections nothing can be seen of the nuclei or substance 

 of the leprosy cells, the cells being marked merely as 

 groups of densely aggregated leprosy bacilli (fig. 143). 

 While, then, the lepra bacilli have characters in staining by 

 which they resemble the tubercle bacilli, they differ accord- 



