566 KlLA-AZAR 



nucleus dividing several times within the protoplasm and a 

 corresponding number of new parasites resulting. 



In view of Leishman's original opinion an extremely important 

 discovery was made by Rogers and later confirmed by Leishman 

 himself, to the effect that in cultures a flagellate organism 

 developed from the Leishman-Donovan body. Cultivation was 

 effected by taking spleen juice containing the parasite, placing it 

 in 10 per cent sodium citrate solution and keeping at 17-24 C. 

 Under such conditions there occurs an enlargement of the 

 organism, but especially of the larger nucleus. This is followed 

 by the appearance of a pink-staining vacuole in the neighbourhood 

 of the smaller nucleus. Along with these changes, in from 24 to 

 48 hours the parasite becomes elongated and the smaller nucleus 

 and its vacuole move to one end ; from the vacuole there then 

 appears to develop a red-staining flagellum, which when fully 

 formed seems to take its origin from the neighbourhood of the 

 small nucleus. The body of the parasite is now from 20-22 //, 

 long and 3-4 p broad, with the flagellum about 22 /x long. The 

 whole development occupies about 96 hours. The formation of 

 an undulating membrane was not observed, and, although the 

 flagellated organism moved flagellum first, like a trypanosome, 

 it is evident that here the relationship of the micronucleus is 

 different as this structure lies anterior to the macronucleus. 

 In his cultures, which kept alive for four weeks, Leishman made 

 a still further important observation. In certain of the flagellate 

 forms he saw chromatin granules develop in the protoplasm often 

 in couples, a larger and a smaller. There then occurred a very 

 unequal longitudinal division of the protoplasm, and a hair-like 

 undulating individual containing one of the pairs of chromatin 

 granules would be split off. At first these would be non- 

 flagellate, but later a red-staining flagellum would appear at one 

 end. The analogies between these observations and those of 

 Schaudinn (v. p. 550) on the relations of spirochaetes to 

 trypanosomes will be at orice apparent; the further develop- 

 ment of these spirillary forms in Leishman's organism could 

 not, however, be traced. 



The facts just detailed have caused considerable discussion as 

 to the classification of the organism, which now usually goes by 

 the name Leishmania donovani, originally given to it by Ross. 

 According to one view, it is to be looked on as a trypanosome, 

 and although, as we have noted, its flagellated form differs from 

 the typical trypanosoma form, it bears considerable resemblance 

 to the members of this group, and as Leishman has pointed out, 

 his cultures may not represent the full development of the 



