LEISHMANIA DONOVANI 633 



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 it at 17 to 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 neighbour- 

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

 twenty-four to forty-eight hours the parasite becomes elongated 

 and the smaller nucleus 

 and its vacuole move 

 to one end; from the 

 vacuole there then ap- 

 pears to develop a red- 

 staining tiagellurn, 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 to 22 /x 

 long and 3 to 4 /u. broad, 

 with the flagellum about 

 22 fji long. The whole 

 development occupies 

 about ninety-six hours. Fl(; 174 ._ Le ishmai 1 -Don van bodies within 

 The formation of an endothelial cell in spleen. See also Plate 

 undulating membrane VI., Fig. 24. xlOOO. 

 \\a- 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 l>e 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 tho-r of Schaudinn (>'. p. GIG) on the relations of spirochsetes 



