TRYPANOSOMA 



393 



and also at the room temperature, good cultures, in which T. lewist 

 varied in size from minute forms i to 2 microns in length up to 50 

 to 60 microns, and colonies of rosettes were seen with all the fiagella 

 turned inwards. The fiagellum in cultivated forms projects directly 

 from the kinetonuclear end of the parasite. 



The following have been cultivated : S. cmzi, by Chagas; T. hrucei, 

 by McNeal and Novy, and by Laveran and Mesnil; T. equimim, by 

 R. Thomas and Breinl, T. eqidperdum, by Thomas and Breinl, 

 with slight success; T. castellanii, by Thomas, Breinl, Gray, and 

 Tulloch, with partial success; T. evansi, by Novy, McNeal, and Hare, 

 and by Thomas and Breinl, but were found to be non-virulent, 

 and subcultures could not be obtained. 



Effects upon the Invertebrate Host.— The effects of trypanosome 

 infection upon the invertebrate host has been but little studied, 

 except with reference to T. castellanii and Glossina palpalis, and 

 the result may be tabulated as follows : — 



A. Non-Infection of the Fly. — i. The trypanosomes intro- 

 duced by the infective feed may entirely disappear, being digested 

 in some fifty to seventy hours. 



2. The trypanosomes may multiply in the crop, but disappear 

 after the next feed if non-infective. 



3. The trypanosomes may grow and multiply in the gut, and yet 

 be all swept out by the next feed if clean. 



4. The trypanosomes may survive and develop in the crop for 

 twelve days, providing that blood is always present, but no trypano- 

 somes appear in the gut, and the infection dies out. 



B. Infection of the Fly Doubtful. — In the third instance 

 quoted above infection may take place; everything depends upon 

 the effects of the second feed. 



C. Infection of the Fly. — The trypanosomes persist after the 

 clean feed has displaced the blood from the gut, but the infection 

 also depends upon the strain of trypanosome, as there is undoubtedly 

 a struggle for existence between the trypanosome and the chemical 

 defences of the fly against T. castellanii. 



Type Species,— Trypanosoma rotatoritim Mayer, 1843. 

 It is necessary, for purposes of classification, that the reader 

 should clearly understand the nature of the type species. 



Trypanosoma rotatorium Mayer, 1843. 



Synonyms. — Paramcecium loricatum, seu costatum Mayer, 1843, Amoeba 

 rotatoria Mayer, 1843, Trypanosoma sanguinis Gruby, 1843, Monas rotatorium 

 Lieberkiihn, 1870, Undulina ranarum Ray Lankester 1871, Paramcecioides 

 costatus Grassi, 1872. 



History. — Gluge in 1842 discovered in the blood of frogs an organism re- 

 sembling that which had been discovered by Valentin in the previous year in 

 Salmo fario, the brown trout, and which was thought to be related to the genus 

 Amoeba of Ehrenberg, but which from his description and from his figures is 

 more probably a trypanosome. Gluge's description is also very short, and he 

 is followed by Mayer, in 1843, who describes two forms — an Amceba rotatoria 

 and a Paramoscium loricatum, or costatum — but in November of the same 

 year Gruby gave a clear description of the organism, and applied the generic 



