Cultivation 



569 



The bodies divide by binary and multiple fission, without 

 recognizable mitotic changes. When multiple fission occurs, 

 the nucleus divides several times before the protoplasm 

 breaks up. The organism is not motile and at this stage has 

 no flagella. 



Cultivation. The organism was first cultivated artificially 

 by Rogers in citrated splenic juice at 17 to 24 C. It can 

 also be cultivated in the blood-serum agar medium used 

 by Novy, MacNeal, and Hall for trypanosomes. 



Under conditions of cultivation the appearance of the or- 

 ganism undergoes a complete change. It enlarges, the 

 nucleus increases greatly in size, and a pink vacuole appears 

 near the blepharoplast. In the course of twenty-four to 



Fig. 197. Leishmania donovani. Flagellated forms obtained in pure 

 cultures (Irishman) . 



forty-eight hours the organism elongates, the blepharoplast 

 moves to one end, and from the vacuole near it a flagellum is 

 developed, and the organism becomes in about ninety-six 

 hours a flagellate protozoan resembling herpetomonas. It 

 now measures about 20 p in length and 3 to 4 {i in breadth, its 

 whip or flagellum measuring about 3 /w additional. It is also 

 motile and, like the trypanosomes, swims with the flagellum 

 anteriorly. There is no undulating membrane. 



This may be regarded as the perfect or adult form of the 

 organism. It multiplies by a peculiar mode of division first 

 observed by Leishman. Chromatin granules, a larger and 

 a smaller, appear in the protoplasm in pairs, after which, 

 through unequal longitudinal cleavage, long, slender, almost 

 hair-like individuals, containing one of the pairs of chromatin 

 granules, are separated. These were serpentine at first, but 



