POSITION OF THE BACILLI. 



271 



Position of the Bacilli. — They occur in enormous numbers 

 in the leprous lesions, especially in the tubercular form. In 

 fact, so numer- 

 ous are they 

 that the granu- 

 lation tissue in 

 sections, prop- 

 erly stained as 

 above, presents 

 quite a red 

 colour under a 

 low power of 

 the microscope. 

 The bacilli oc- 

 cur for the most 

 part within the 

 protoplasm of 

 the round cells 

 of the granula- 

 tion tissue, and 

 are often so 

 numerous that 

 the structure 

 of the cells is 



quite obscured (Fig. 97). They are often arranged in bundles 

 which contain several bacilli lying parallel to one another, 

 though the bundles lie in various directions (Fig. 98). The 

 appearance thus presented by the cells filled with bacilH is 

 very characteristic. Bacilli are also found free in the lym- 

 phatic spaces, but the greater number are undoubtedly con- 

 tained within the cells. They are also found in spindle-shaped 

 connective-tissue cells, in endothelial cells, and in the walls of 

 blood-vessels. They are for the most part confined to the 

 connective tissue, but a few may be seen in the hair follicles 

 and glands of the skin. Occasionally one or two may be found 

 in the surface epithelium, where they probably have been carried 

 by leucocytes, but this position is, on the whole, exceptional. 

 They also occur in large numbers in the lymphatic glands 

 associated with the affected parts. In the internal organs — 

 liver, spleen, etc., when leprous lesions are present, the bacilli 



Fig. 98. — High-power view of portion of leprous nodule, show- 

 ing the arrangement of the bacilli within the cells of the granulation 

 tissue. 



Paraffin section ; stained with carbol-fuchsin and methylene-blue. 

 X 1 100. 



