335 
An unidentified parasite 
Another parasite, a round, red-staining mass from i'5 to in 
diameter, is found in red cells (Plate XXIX, figs. 93, 95, 99). With it 
are associated bluish-green, crystal-like bodies (Plate XXIX, figs. 93, 
95,97,98). Both the red masses and crystals may be present in 
varying numbers (Plate XXIX, figs. 98, 99). The cytoplasm of the 
host-cells is usually stained a deeper blue than usual. Many of the 
smaller red masses have a well-defined blue area around them, which 
suggeststhat this parasite possesses a cytoplasmic body (Plate XXIX, 
figs. 94, 96). In stained films of fresh blood the red masses do not 
seem to have much structure, but in films of blood kept for two days, 
the structure consists of chromatic granules arranged peripherally with 
one or two darker chromatic granules in the centre. 
This parasite with its crystals was seen in fresh specimens. It 
occurred in conjunction with drepanidia and T. loricatum. 
FISHES* 
Fresh-water fish of many different sorts were examined in the 
Gambia and in the Congo. Parasites were found only in the fish 
without scales, mentioned below. 
Those infected were caught in a very small sluggish stream with 
a very dirty bottom ; none of them were over seven inches in length 
and none were infected with drepanidia. 
Trypanosomes (Plate XXX). 
Two “mudfish ” ( C/arias angolensis ) caught at Leopoldville in 
the Congo Free State on December 9th and December 30th, 1903, 
had actively motile trypanosomes in their blood which may be 
divided into three types; a small, a medium, and a long form. The 
small type was identical in both, the medium was present in both, but 
with slight differences, and the long form was present only in the fish 
°f December 9th. The small form was very frequently seen in the 
fish of December 30th, while in the fish of December 9th, only four 
were present in a total of ninety-nine parasites. The medium form, 
>n the fish of December 30th, was less frequently met with than the 
small form, but was often seen in the fish of December 9th- 
Of the long forms only thirteen were seen. All the forms were 
characterised by the possession of a large four-lobed ble pharoplast, 
*The description of the parades found in fishc-s is republished by permission from the 
Journal of Medical Research. 
