696 INFECTION AND IMMUNITY. 



X. KALA-AZAH. 



Kala-azar, or febrile splenomegaly, is a tropical 

 disease, especially of India and China, associated 

 with great enlargement of the spleen, often of the 

 liver, extreme cachexia and anemia. The disease 

 was formerly looked on as a malarial cachexia. 



Both Leischman and Donovan described bodies 

 in stained preparations of splenic pulp and 

 ascribed to them an etiological significance. These 

 observations have been confirmed repeatedly. The 

 bodies are small round mass of cytoplasm, which 

 with the Eomanowski stain is colorless. Two 

 masses of chromatin ? one much smaller than the 

 other, take a purplish stain. The whole body is 

 from, 2 to 3 microns in diameter. Eogers suc- 

 ceeded in cultivating the organisms in blood 

 slightly acidified with citric acid and incubated at 

 22 C. In this way a flagellated form was ob- 

 tained which is similar to trypanosomes in mor- 

 phology. The classification, however, is not yet 

 certain. The organism is distributed throughout 

 the body, but is most numerous in the spleen, bone 

 marrow, and liver. 



Patton succeeded in obtaining growth of the 

 parasite in the stomach of the bed bug, and it 

 seems probable that transmission occurs in this 

 way. Rogers, acting on this supposition, was able 

 to reduce the number of cases by ridding the 

 houses of bed bugs. 



