PARASITIC PROTOZOA IN RELATION TO THE WAR. 307 



by loiigitucliiial tission, and consequently thinner and thicker forms 

 are found. Some of the stotit forms of T. rhodesiense have the 

 nucleus posterior, that is, near the blunt non-flagellar end of the 

 Ixjdy (I'ig. 15). As before mentioned, sleeping sickness is 

 spread by tsetse flies. At the same time note must be made of 

 natural reservoirs of human and animal trypanosomes. It has 

 been shown that various antelopes and other big game harbour 

 the trypanosomes of Rhodesian sleeping sickness, but are un- 

 aiit'ected thereby. The infection in the antelopes may not be a 

 very heavy one, but the bii;' game act as reservoirs whence 

 Glossincc can acquire trypanosomes that may be transmitted to 

 man with fatal results, thotigh fortunately the blood serum of 

 many persons is fatal to T. rhodesiense. Trypanosomiasis may 

 be controlled by various organic preparations of arsenic and anti- 

 mony, such as atoxyl, tartar emetic, etc. 



Other protozoal diseases which may be encountered by the 

 Forces in India and Mesopotamia are due to the various species 

 of Lcishmania (such as L. donovani and L. tropiea), the causal 



Fig. )7. 



Fig. 10. 



agents of kala-azar and of Oriental sore. The leishmaniases are 

 probably transmitted by insects, such as bugs, fleas, lice, mos- 

 quitos and sand flies, in which the Leishmania may pass through 

 a herpetomonad stage (Fig. 16). The non-flagellate, oval form 

 or Leishman-Donovan body, is the stage of the parasite com- 

 monly found in man (Fig. 17). Leishmaniases may be success- 

 fully treated by intravenous injections of tartar emetic. 



The detection of these parasites and others of a similar 

 nature necessitates microscopical examination by highly trained 

 workers. 



Blood Spirochetes. 



The chief relapsing fevers are due to two principal 

 spirochajtes or varieties thereof. African tick fever is due to 

 Spiroclucta duttoni, and is transmitted 'by the tick Ornithodorus 

 monbata and allied species. European relapsing fever is due to 

 Spiroch'sta rccurrentis. and is transmitted by body lice. Each 

 spirocha^te has a sinuous elongate body, with a diffuse nucleus 

 of minute chromatin granules (compare Fig. 10). 6". duttoni in 

 human blood measures 12// to 16 /i, long, is 0.25 /t to 0.5 /x broad, 

 and has j)ointed ends. S. recurrentis varies from y fj. to 19 /x in 



