166 
E. A. MINCHIN AND H. M. WOODCOCK. 
all we can do is to direct attention to it. Unfortunately, in 
tlie course of very numerous observations on birds infected 
with trypanosomes, neither of us has ever seen anything in 
the least corresponding. 
Morphology of the Trypanosomes as seen in the Permanent 
Preparations. 
All our permanent preparations are in the form of smears. 
Both the two chief methods of preparing films were employed, 
namely : (1) fixation by osmic acid vapour, followed by abso- 
lute alcohol, and then staining by Giemsa; and (2) wet fixa- 
tion of smears made on cover-slips, either by sublimate-acetic 
mixture or by Schaudinn’s fluid, and then staining by iron- 
haematoxylin. The details of our use of both these methods 
have already been described (see Minchin [ 13 ] and Minchin 
and Woodcock [ 14 ]), so they need not be repeated here. The 
drawings are all magnified 2000 times, so that a particular 
individual can be at once compared with any other. 
The type or types of form presented by the parasites varied 
in different birds. In the early owls infected with trypano- 
somes (Nos. 8 and 18), three readily distinguishable types 
occurred, as has been indicated above in our account of the 
observations made on the living, active parasites. These 
three types maybe distinguished as small, medium, and large 
respectively. While each type has sharply defined charac- 
teristics, and at the first glance might be regarded as 
representing a parasite quite distinct from both the others, 
nevertheless, as will be seen below, forms occur which are 
transitional in character from one type to the other, and 
there can be no doubt, we think, that all three are only 
different phases of one and the same trypanosome. 
The small type of individual (figs. 1, 2, 14, 32-35) is spindle- 
like or fusiform in shape. The aflagellar extremity of the 
body is abrupt and conical, the kinetonucleus being situated 
close to the end. The undulating membrane is relatively 
quite well developed, and the free flagellum is fairly long 
