36 TRYPANOSOMA 
Coming to a still more recent date, Aldo Castellani, in 
June, 1903, discovered an entirely new form of trypanosoma 
in the blood and cerebro-spinal fluid of patients suffering 
from sleeping sickness in Uganda on the shores of the lake 
Victoria Nyanza, in Central Africa. 
So far in Queensland and possibly Australia Trypanosoma 
have only been demonstrated in the blood of rats, but I have 
proved their existence in at least three distinct species, 
viz., mus decumanus, the common brown rat: mus rattus, 
the old English black rat, which has very large, thin round 
ears, and a somewhat long, tapering tail; and mus Alex- 
andrinus rufus, which is probably a hybrid between the brown 
and the black rat possessing all the morphological characters 
of the latter, but having a reddish-brown coat. 
My observations are confirmatory of Crookshank’s, 
in that rats having these parasites in their blood are appar- 
ently healthy. 
EXAMINATION OF FRESH AND STAINED SPECIMENS. 
If a drop of blood from a surra rat be examined under 
the microscope with } objective it appears to quiver with life, 
and even with an oilimmersion lense the parasites-are extremely 
difficult to examine until their movement is arrested for a 
moment or they are imprisoned in the serum areas. As they 
are so actively motile they form very fascinating objects 
for the microscopist. A single organism will lash its flagellum 
in all directions as though endeavouring to free itself from its 
environment of red and white blood corpuscles. The body 
readily twists upon itself or from side to side with great ac- 
tivity. It can turn completely round with lightning rapidity | 
so that the flagellum will be lashing the blood cells for a mo- 
ment in one direction, and then suddenly lash them in the 
opposite direction. 
Sometimes it will spin round on its long axis and then 
at an incline on its short axis. Occasionally it appears as 
if attached by means of the spine-like process to a corpuscle, 
remaining stationary or lashing its flagellum. At first sight 
they appear to wriggle along either backwards or forwards, 
but the general mode of progression is by means of the fla- 
