KALA-AZAR 



or of a light greenish tinge, and may then be mistaken 

 for blood platelets. 



The organisms are best seen when stained by one 

 of the modifications of Romanowsky's method. So 

 stained, they appear as sharply defined, round or oval 

 bodies, between 2 //- and 3 p in diameter, of a faint 

 blue colour, and containing two masses of chromatin ; 

 one large, round, of a light violet colour, the other small 

 and rod-shaped, and staining a deep red, almost black. 

 The two chromatin masses are usually situated in the 



FIG. 48. 



shorter diameter of the oval-shaped parasites, the larger 

 at one pole, the rod at the other, with its length directed 

 at the larger mass across the body of the parasite. The 

 rod is usually sharply defined, but is sometimes reduced 

 to a mere dot of deeply staining chromatin. The 

 organisms are remarkably uniform both in size and 

 appearance ; they appear to possess a strong cell wall 

 which resists distortion, and the relative size and position 

 of the chromatin masses are very constant. The cytoplasm 

 of the parasite shows little or no structure, but sometimes 



