818 



THE FLAGELLATA 



For stained preparations the deposit obtained on centrifuging the cerebro- 

 spinal fluid is not very satisfactory and the preparations made from it are 

 always poor. Trypanosomes stain better in blood films but as they occur 

 only in small numbers in human blood it is better to inoculate an animal 

 and stain films of the animal's blood. 



Greig and Gray, Dutton and Todd, and Beck recommend puncturing an 

 hypertrophied lymphatic gland with an ordinary hypodermic syringe and 

 examining the drop of gland juice thus obtained. [" Gland puncture is by 

 far the most efficient method of demonstrating the presence of trypanosomes 

 in cases of trypanosomiasis " (Dutton and Todd).] 



Nattan-Larrier and Tanon have always been able to find the parasite in 

 films made with blood obtained by scarification of the erythematous patches 

 on the skin. 



Morphology. The human trypanosome has all the ordinary generic char- 

 acters of other trypanosomes. It is highly motile [but exhibits but little 

 or no translatory power in the field of the microscope (Bruce)]. The cyto- 

 plasm contains chromatin granules : the nucleus is oval and situated in the 

 centre of the parasite : the undulating membrane is narrow : and the 

 flagellum, representing as a rule about one-quarter of the total length of the 

 trypanosome, occasionally has no free portion at all, the cytoplasm extending 

 to the distal extremity of the flagellum. The centrosome stains well. Some- 

 times a vacuole is seen round or near the centrosome : [Laveran and Mesnil 

 regard this as a result of deficient technique, but Nabarro thinks that vacuoles 

 are normally present at times]. 



[The trypanosome is 15-33/* long and in breadth averages 1'5/* in the long 

 to 2*5/* in the short and stumpy forms (Bruce). Great differences are 

 sometimes found in the average length in the same individual. For instance 

 in one case, an European, at the beginning of the illness the trypanosomes 

 averaged 17/x in length whereas at a later date they averaged 25*8/*.] Multi- 

 plication takes place by longitudinal fission (p. 803). 



FIG. 394. Different appearances presented by Trypanosoma gambiense. 

 n, Nucleus ; c, Centrosome ; m', m, Undulating membrane ; n, flagellum. 



[T. gambiense, " like T. brucei, is markedly dimorphic. In size and general 

 appearance also these two species so closely resemble one another that one 

 might easily believe them to be varieties of the same species. There are, 

 however, some slight differences in morphology, . . . but whether these differ- 

 ences will bear the test of more extended observations remains to be seen " 

 (Bruce).] 



