LEISHMANIASIS 269 



common in arthropods and are difficult to distinguish from the flagellate 

 stage of leishman bodies. 



The genera Herpelomonas (Leptomonas) and Crlthidia are frequently found in the 

 alimentary tract of insects and have caused confusion in the search for developmental 

 forms of various pathogenic flagellates in transmitting insects. In Herpetomonas, of 

 which the type species is H. muscoe domestic^, the body is spindle-shaped with a 

 rather blunt flagellar end and an attenuated anterior end. In Crithidia both extremi- 

 ties are pointed and the blepharoplast is situated toward the center quite near the 

 trophonucleus. In Herpetomonas the blepharoplast is near the rather blunt 

 flagellar extremity at some distance from the nucleus. 



There is no undulating membrane in Herpetomonas and only a slightly developed 

 one in Crithidia while Trypanosoma has a fully developed one. In Herpetomonas 

 the blepharoplast is near the flagellated end and at a distance from the trophonucleus. 

 In Crithidia the blepharoplast is more posterior and near the macronucleus but still 

 anterior to it while in Trypanosoma the blepharoplast has moved so far posteriorly 

 as to pass the nucleus and be located at the posterior extremity. The flagellated 

 Leishmania is morphologically herpetomonad. 



Very definite is our knowledge of the cultural forms of Leishmania. Rogers first 

 cultured material from splenic juice of kala-azar patients in 10% sodium citrate solu- 

 tion at a temperature of 1 7 to 24C. The medium was slightly acidulated with citric 

 acid. There was no satisfactory development at blood temperature. In forty-eight 

 hours the oval parasites have developed into herpetomonad flagellates, from 20 to 

 22 microns long by 3 V microns broad, with a 2o-micron flagellum which takes origin 

 from the blunt anterior end of the body near the blepharoplast. The peripheral 

 blepharoplast and centrally placed macronucleus are at a distance from one another 

 as opposed to the approximation of the crithidial blepharoplast to the centrally 

 placed nucleus in a body with pointed anterior end. 



Formerly it was thought that there were differences in the three 

 species of Leishmania from the standpoint of growth on various culture 

 media, L. donovani not growing on N. N. N. medium while L. infantum 

 grew well on N. N. N. medium but not in citrated blood. It is now 

 known that both species will grow on these two media. 



It is absolutely essential in culturing L. donovani or L. infanttim that the blood 

 agar or citrated blood be sterile, as any bacterial contamination prevents growth. 

 With the parasite L. tropica, however, bacterial contamination does not inhibit 

 development and statements have even been made that growth is favored by a 

 staphylococcal symbiosis. L. tropica, it would seem, will develop into flagellated 

 forms in cultures at 28C. while it will be remembered that Rogers in his original 

 experiments failed to obtain other than commencing signs of division at 27C., 22C. 

 being the temperature necessary for the development of flagellate forms. 



L. tropica from South American cutaneous leishmaniases seems to grow more luxur- 

 iantly on N. N. N. medium than does that of oriental sore of Asia and Africa. 



While differences in development on different culture media may 

 obtain not only with different species but with different strains of the 



