KALA-AZAR AND ORIENTAL SORE 191 



cant of the geographical distribution of the latter 

 disease, for it is far from being confined to the East, 

 and unfortunately has spread along the shores of 

 the Mediterranean and has invaded the New World. 

 The third of these nearly allied complaints afflicts 

 children more than adults, and is consequently 

 known as Infantile Kala-azar. This has a special 

 interest, inasmuch as dogs, too, are infected by it 

 and can communicate it to children associating 

 with them. It is proposed to consider each of these 

 diseases in some detail, but it is necessary to men- 

 tion that they are due to three species of the blood- 

 parasite known as the Leishman-Donovan body. 



Indian Kala-azar is due to the parasite known as 

 Leiskmania (or Herpetomonas) donovani. It is parasitic 

 not only in the blood, but in the cells lining the 

 bloodvessels of the spleen, liver, lymphatic glands, 

 bone marrow, and intestinal canal. Leishmania 

 donovani thus is distributed through the human 

 system and usually has fatal effects. Oriental sore, 

 on the other hand, is more restricted to the skin 

 and is usually benign. Infantile Kala-azar, when 

 once established, commonly runs a fatal course in 

 children. 



The parasites of Indian Kala-azar (Fig. 38) 

 occur sometimes singly, more often in clusters within 

 their host cell, which is often a leucocyte or a cell 

 from the lining of the bloodvessels. They are most 

 abundant in the spleen and liver. Each parasite 

 (Fig. 38, A-D) strongly resembles the non-flagellate 

 stage of ordinary Herpetomonads. It possesses a 

 definite body, an oval nucleus, and usually a bar- 



