•LEISHMANIA TROPICA 675 



organism. The view has been advanced that infection takes 

 place by the agency of fleas. 



Leishmania Tropica. — In various tropical and sub-tropical 

 regions (India, Central Asia and the East, Northern Africa, 

 Scfnthern Russia, Turkey, South America, West Indies) 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. The work of J. H. 

 Wright first showed that a protozoal parasite is concerned in the 

 etiology of the condition. 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 defined bodies, 2 to 4 fi in diameter. When stained by 

 a Romanowsky combination there was found to be a peripheral 

 l 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 intracellular in position in the lesion, as many as twenty 

 being in one cell, and that the type of cell containing them was, 

 as in kaia-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. Various views have been held as to how infection 

 takes place, but Patton believes the bed-bug to be the inter- 

 mediate host perhaps exclusively during its nymph stage. The 

 iacubation period before the sore develops is about two months, 

 and its duration is about a year. It is stated that after recovery 

 the individual possesses immunity. Sometimes the parasite is 

 destroyed in a foul ulcer, but it can be obtained by taking some 

 of the juice from the marginal indurated tissues by capillary 

 glass tubes. Patton reports having found the organism in the 

 blood taken from parts adjacent to the ulcer. Row has obtained 

 cultures in citrated blood, and Nicolle and Manceaux have re- 

 produced the condition in man, the monkey, and the dog, both 

 by virus obtained from the natural infection and from cultures 

 on Novy and MacNeal's medium. The lesions were identical 

 with those naturally occurring, but the incubation period was 

 often many months. In the male mouse intraperitoneal injection 

 is followed either by a granuloma in the testicle or by a general- 

 ised infection in which lesions often characterised by widespread 

 destruction of tissues occur in the skin or around the joints; all 



