S UBFA MIL Y TR YFA NOSOMINJl 



381 



which we shall presently suggest a classification (vide p. 395), 

 and the genera Endotrypanum, Schizotrypanum, and Rhynchoido- 

 monas. 



Trypanosoma Gruby, 1843. 



Synonyms. — Amoeba Mayer, 1843; Paramcecium Mayer, 1843; 

 Globularia Wedl, 1850; Undulina Lankester, 1871; Herpetomonas 

 Kent, 1878; Hcematomonas Mitrophan, 1883; Trypanosomonas 

 Danilewsky, 1885; TrypanozodnJ^neh.e, 1906. 



Definition. — -Trypanosominse, with the periplast raised into a 

 longitudinal undulating membrane, along which the single flagellum 

 runs. 



Historical. — The history of the genus has been largely detailed 

 in Chapter L, and we need only remind the reader it commenced 

 by Valentin, in 1841, reporting minute bodies in the blood of 

 Salmofario Linnaeus, the brown trout, which induced Gluge to bring 

 forward his discovery of Trypanosoma sanguinis in frog's blood, 

 while Gros, in 1845, found them in mice and moles. Later, in 1850, 

 Wedl found the same parasites in the blood of birds and mammals, 

 while Chaussat in the same year and Lewis in 1879 found them in 

 rats, and Danilewsky studied their structure and started interest in 

 them. 



Morphology. — The usual form in which trypanosomes are found 

 in vertebrate blood is that of an elongated, spindle-shaped mass of 

 cytoplasm composed of an inner granular endoplasm, and surrounded 

 by ectoplasm (periplast). The shape of the parasite is, however, 

 by no means always a spindle, but, on the contrary, varies con- 

 siderably in different species, and may even be rounded. 



In the endoplasm is situated a trophonucleus, often called the 

 ' nucleus,' concerning the structure of which there is considerable 

 difference of opinion. Some authorities — e.g., Prowazek, etc. — 

 with regard to the nucleus of T. lewisi and T. brucei, and Miss 

 Robertson, with regard to T. raice, say that the nucleus is complex 

 and resembles the description already given for that of Hcemoproteus 

 noctucB, that of T. lewisi having eight chromosomes and a centrosome 

 connected by a strand. 



Other authorities, like Ross and Moore, Breinl and Hindle, con- 

 sider that observers have been led astray by using dried films; for, 

 according to them, though pretty pictures of the parasite are pro- 

 duced by this method, still, such delicate structures as the details 

 of the nucleus are ruined ; and therefore, in order to study these 

 bodies accurately, the films must be fixed while wet in such a reagent 

 as Fleming's fluid, and suitably stained. If this is done properly, 

 according to them, it is seen that the nucleus is a vesicle bounded by 

 a nuclear membrane, and having in its centre one small chromatin 

 sphere, called by some the intranuclear centrosome. 



Situated somewhere in the cytoplasm, and generally near the 

 afiagellar extremity, is another mass of chromatin, the kinetonucleus. 

 From this kinetonucleus a faint strand — the rhizoplast — proceeds, 



