A. Balfour 
53 
on an average, 4 mm. in length and contained the usual spores or sporo¬ 
zoites lying in a milk-white and cheesy medium which could be easily 
smeared out upon a slide and contained what looked like minute 
crystals. The spores themselves, which in different cysts were at 
different stages of development, varied in shape and size in the living, 
unstained condition. Measured, when in normal salt solution, by 
means of a micrometer eye-piece, the crescentic forms were found to 
vary from 13 to lb fx in length, and from 3 to 4'5 p, in breadth at their 
widest portion, i.e. the centre of the spore. Smaller spherical forms had 
a diameter of 8 /r. There were also present larger, very pale, spherical 
bodies containing granules and measuring about 13 p, in diameter. 
I cannot be certain that these were spores; they may have been 
examples of the pansporoblast stage of Doflein. 
The crescentic or sickle-shaped spores, when stained by the Giemsa 
method, were found to measure from 15 to 16'5 fx in length, while the 
breadth at their widest parts varied from 3 to 3'5 /r. The stout, some¬ 
what oval forms were usually IS /x x lb /x. 
These measurements were first made by using the micrometer 
eye-piece; they were afterwards confirmed in Khartoum, emplojung 
Bruce’s method of measuring drawings made at a magnification of 
2000 diam. by means of a Greil’s projection apparatus. 
The description given by Ross (1910) of sarcocyst spores in the ox, 
which were indistinguishable from the spores contained in the large 
cysts found in Grant’s gazelle, applies almost equally wmll to the spores 
in G. rufifrons. 
It is as follows : 
“ There are two types, a sausage shaped or oval form and a more 
elongated form. The latter are distinctly more pointed at one end. 
The distribiition of the chromatin is the same in both forms. At one 
end—the more pointed end in the long forms—there is a dense mass of 
chromatin completely filling the end, no protoplasm being visible be¬ 
tween the chromatin and the edge of the parasite. At the opposite 
end is another mass of chromatin which is not, however, terminal. 
Protoplasm can be clearly seen all round it, and the appearance of the 
chromatin is quite different to that at the other end. The latter stains 
deeply and uniformly, the former takes a paler stain and has more 
deeply stained chromatin granules scattered thi'oughout.” In the case 
of the Sudan parasites (fig. 1) this latter chromatin, which consists 
wholly of scattered granules, lies in a clear, unstained area which 
sti’etches from side to side of the spore. The more elongated spore 
