264 LEPROSY. 



numerous that the structure of the cells is quite obscured 

 (Fig. 70). They are often arranged in bundles which con- 

 tain several bacilli lying parallel to one another, though the 

 bundles lie in various directions (Fig. 71). The appearance 

 thus presented by the cells filled with bacilli is very character- 

 istic. Bacilli are also found free in the lymphatic spaces, 

 but the greater number are undoubtedly contained within 

 the cells. They are also found in spindle-shaped con- 

 nective 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 are also found though in 

 relatively fewer numbers. In the nerves in the anaesthetic 

 form they are comparatively few, and in the sclerosed 

 parts it may be impossible to find any. There are few 

 also in the skin patches referred to above as occurring in 

 this form of the disease. 



Their spread is chiefly by the lymphatics, though distri- 

 bution by the blood stream also occurs. They have been 

 said to be found in the blood during the presence of fever 

 and the eruption of fresh nodules, and they have also been 

 observed in the blood vessels post mortem, being chiefly 

 contained within leucocytes. Recent observations (e.g., 

 those of Doutrelepont and Wolters) show that the bacilli 

 may be more widely spread throughout the body than was 

 formerly supposed. A few may be detected in some cases 

 in various organs which show no structural change, especially 

 in their capillaries. The brain and spinal cord are practically 

 exempt. 



Relations to the Disease. Attempts to cultivate the 

 leprosy bacilli outside the body have so far been unsuccess- 

 ful. From time to time announcements of successful culti- 



