272 LEPROSY 



obscured (Fig. 92). They are often arranged in bundles which 

 contain several bacilli lying parallel to one another, though the 

 bundles lie in various directions (Fig. 93). The appearance thus 

 presented by the cells filled with bacilli is very characteristic. 

 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 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 are also found though in relatively smaller 

 numbers. In the nerves in the anaesthetic form they are com- 

 paratively 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 distribution 

 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, 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 arid spinal cord are almost exempt, 

 but in some cases bacilli have been found even within nerve 

 cells. 



Relations to the Disease. Attempts to cultivate the leprosy 

 bacilli outside the body have so far been unsuccessful. From 

 time to time announcements of successful cultivations have been 

 made, but one after another has proved to be erroneous. A 

 similar statement may be made with regard to experiments on 

 animals. If a piece of leprous tissue be introduced subcutaneously 

 in an animal, such as the rabbit, a certain amount of induration 

 may take place around it, and the bacilli may be found unchanged 

 in appearance weeks or even months afterwards, but no multi- 

 plication of the organisms occurs. The only exception to this 

 statement is afforded by the experiments of Melcher andOrthmann, 

 who inoculated the anterior chamber of the eye of rabbits with 



