1909. ] BLOOD-PARASITES OF FRESHWATER FISHES. is 
2. TRYPANOSOMA GRANULOSUM Lay. & Mesn. (Plate I. figs. 1-7 ; 
Plate V. figs. 78-93.) 
The trypanosome of the Hel has been seen by many observers, 
and there is no other fish-trypanosome which has been the object 
of so many memoirs. According to Laveran and Mesnil, the first 
description of this parasite was by Sabrazés and Muratet, but the 
earlier work of these authors is not accessible to me. The earliest 
memoir on the subject with which I am acquainted is that of 
Laveran and Mesnil themselves (1902), in which they figure and 
describe the parasite and name it 7’. granulosum. Lebailly (1906) 
gave a detailed description, with two figures, of this trypanosome 
and distinguished two varieties, magna and parva. In the same 
year Brumpt described the transmission of the trypanosome of 
the eel by the leech Hemiclepsis, and the development that the 
parasite goes through in this leech. Finally, Franca (1907) has 
devoted a memoir to this trypanosome. 
Since so much work has been done on the trypanosome of the 
eel, I did not pay much attention to it, not expecting to be able 
to add much to our knowledge on this subject. I obtained four 
eels caught in the Broad and examined one of them, which I 
found to contain trypanosomes most abundantly, more so than 
any fish I have yet examined. I made a number of smears and 
preparations from this eel and then sent all four eels to the 
kitchen, to be prepared for my next meal; it was not found that 
infection with trypanosomes impaired appreciably their gastro- 
nomic properties. I much regretted afterwards that I did not 
examine the other three eels to see if they were equally well 
infected. 
Sabrazes & Muratet (1904), Lebailly (1906), and Franea (1907), 
have all drawn attention to the extraordinary vitality of this 
trypanosome, and the fact that if a drop of blood containing them 
be sealed up on a slide under a coverslip, the trypanosomes will 
live for several days and multiply. I have not imitated these 
experiments, but I had a drop of blood under a coverslip, not 
sealed up in any way, in which the trypanosomes were moving 
actively after 24 hours, less actively after 48 hours, and feebly 
after 72 hours. 
I spent some time watching the movements of this trypano- 
some, which are extraordinarily snake-like. As in the case of 
T. perce, the movements are of two kinds, conveniently distin- 
guished as wriggling and travelling. They may wriggle for a long 
time without changing place to any considerable extent, and then 
they may suddenly start travelling. When they become weaker, 
after 24 hours under a coverslip, they only wriggle and do not 
travel, and as they become moribund the wriggling movements 
become weaker and weaker, till on the third day they are very 
feeble. When wriggling they twist over and over in S8-like 
curves, appearing at the first glance like a writhing knot. When 
travelling, I observed them always progressing actively in a 
definite direction, flagellum forwards, the body twisting from 
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