636 LEISHMANIOSIS 



regions (India and the East, Northern Africa, Southern Russia, 

 South America) there is widely prevalent a variety of very 

 intractable chronic ulceration which goes by various names in 

 different parts of the world Delhi sore, tropical ulcer, Aleppo 

 boil, etc. Various views were formerly held as to the pathology 

 of the condition, but the work of J. H. Wright makes it 

 practically certain that a protozoal parasite is concerned in its 

 etiology. In the discharge from the ulcer and in sections of a 

 portion of tissue excised from a case coming from Armenia, 

 Wright observed great numbers of round or oval, sharply denned 

 bodies, 2 to 4 /x in diameter. When stained by a Romanowsky 

 combination there was found to be a peripheral portion coloured 

 a pale blue and a central portion tending to be unstained ; there 

 were also two chromatin bodies, one larger, occupying a fourth 

 or a third of the whole and situated in the periphery, another 

 smaller, round or rod-shaped, and of a deeper colour than the 

 larger mass. It was found that the bodies were usually intra- 

 cellular in position in the lesion, as many as twenty being in one 

 cell, and that the type of cell containing them was, as in kala- 

 azar, that derivable from endothelial tissues. 



Wright's observations have been . fully confirmed by workers 

 in various parts of the world, and it is now recognised that in 

 these tropical ulcers we have a third example of the activity of 

 a Leishmania. This is corroborated by the work of Row, who 

 has obtained cultures in citrated blood, corresponding to those 

 of the other two species. Nicolle and Manceaux have also 

 cultivated the organism on Novy and MacNeal's medium, and 

 have reproduced the condition in man, the monkey, and the dog, 

 both by virus obtained from the natural infection and from 

 cultures. The lesions were identical with those naturally occur- 

 ring, but the incubation period was often many months. It 

 may be said that Thompson and Balfour have described in the 

 Soudan a condition in which subcutaneous nodules without 

 ulceration occurred in man and these contained Leishmania 

 bodies. 



At present the tendency is to look upon the three Leishmanise 

 as representing different species, but further investigation is here 

 necessary. It has been pointed out that in kala-azar, skin 

 ulcerations occur which might link this condition with tropical 

 ulcer, but it is to be noted that, while in the latter enormous 

 numbers of the parasite are found, in the ulcers of kala-azar, on 

 the other hand, parasites are difficult to find. Again, Nicolle 

 has found that dogs infected with Leishmania tropica appeared 

 to be not so susceptible to subsequent infection with Leishmania 



