558 Sleeping Sickness 



Thomas and Linton* and Laveran,| who, by means of 

 animal experiments, determined not only the complete 

 identity of the organisms, but their uniform virulence. 



Morphology. Trypanosoma gambiense is a long, slender, 

 spindle-shaped, flagellate micro-organism that measures 17 

 to 28 ^ in length and 1.4 to 2 ^ in breadth. From the ante- 

 rior end (that which moves forward as the organism swims) 

 a whip-like flagellum projects about half the length of the 

 organism. The terminal third of the flagellum is free in 

 most cases. The proximal two-thirds are connected with a 

 band of the body substance, which is continued like a ruffle 

 along one side of the organism to within a short distance of 

 its blunt posterior end, where the flagellum abruptly ends 

 at the blepharoplast. This thin ruffle is known as the un- 

 dulating membrane. By means of the flagellum and the 

 undulating membrane the organism swims rapidly with a 

 wriggling and rotary movement that give it the name Try- 

 panosome, which means " boring body." 



The protoplasm is granular and often contains chromatin 

 dots that are remarkable for their size and number. There 

 is a distinct nucleus of ovoid form. There is also a cen- 

 trosome or blepharoplast, which appears as a distinct deeply 

 staining clot near the posterior blunt end and from which the 

 flagellum appears to arise. Near this a vacuole is sometimes 

 situated. 



Staining. The organisms are best observed when stained 

 with one of the polychrome methylene-blue combinations 

 Irishman's, Wright's, Jenner's, Romanowsky's, Marino's. 

 To stain them a spread of the blood or cerebrospinal fluid is 

 made and treated precisely as though staining the blood for 

 the differential leukocyte count or for the malarial parasite. 



Cultivation. The cultivation of Trypanosoma gam- 

 biense has not yet been achieved. This seems singular, as 

 Trypanosoma lewisi of the rat and Trypanosoma brucei of 

 "nagana" or "tsetse-fly" disease of Africa have been culti- 

 vated by Novy and McNealf in mixtures composed of 

 ordinary culture agar-agar and defibrinated rabbit-blood, 

 combined as necessary, 1:1, 2:1, 1:2, or 2 13, etc. The 



* "Lancet," May 14, 1904, pp. 1337-1340. 



t "Compt.-rendu de 1'Acad. des Sciences," v, 142, 1906, p. 1065. 



J "Contributions to Medical Research dedicated to Victor Clarence 

 Vaughan," Ann Arbor, Michigan, 1903, p. 549; "Journal of Infectious 

 Diseases," 1904, i, p. i. 



