168 
E. A. M1NCHIN AND H. M. WOODCOCK. 
point where the cytoplasm ends and the flagellum becomes 
free. 
The cytoplasm of both the types of form just described is 
coloured either pale blue or a faint lilac in Giernsa smears. 
Usually it appears fairly homogeneous in character (figs. 20, 
21), but now and then it contains granules, more or fewer, 
which stain dark red (fig. 8). 
The third distinct variety of form shown by the trypano- 
some is very large, and also differs markedly from the other 
two types in the appearance of the cytoplasm (figs. 9-11, 
22, 24). This is very dense, and in Giemsa-stained smears is 
coloured a deep and intense blue, which may be slightly 
tinged with purple or lilac. The aflagellar region of the 
body is prolonged for some distance beyond the kineto- 
nucleus. It usually tapers to a fine extremity, but it is never 
so narrow and attenuated as in the medium-sized parasites, 
because in these large forms the body is much broader at the 
level of the kinetonucleus than in the latter. The undulating 
membrane may be very prominent, especially towards the 
flagellar end of the body. The dimensions of some of the 
largest of these forms (figs. 10, 22 and 24) are as follows : 
Total length 54-60 /x, greatest width 5|-6 /x, length of afla- 
gellar prolongation 12-15 /x, and length of free flagellum 8h /x, 
the last named being comparatively short. A rather shorter 
but broader individual (fig. 11) measures 50 j u in length, 
6J j u in width, while the aflagellar part is 9 /u long, and the 
fhigelluin again 8J ju. 
In wet films, stained by iron-hsematoxyliu, this type is 
readily distinguishable (figs. 43 and 44), both by its general 
shape, which agrees quite well with appearance of similar 
parasites on the other smears (allowing for a uniform shrink- 
age in size), and also by the staining reaction of the cytoplasm, 
which is stained dark grey, a much deeper tint than in the 
case of the small or medium-sized individuals, whose cyto- 
plasm is quite pale or else only slightly stained. The largest 
examples of this type, as seen in wet films, measure 44 /x in 
length, 4J /u in breadth, the aflagellar region is 7 /x long, and 
