ON THE TRYPANOSOME OF THE LITTLE OWL. 
145 
the death of this bird trypanosomes were readily found in its 
bone-marrow. When owl 7 died a few weeks later its bone- 
marrow was examined carefully, but no trypanosomes were 
seen and other parasites were also very scarce ; consequently, 
only very few preparations were made from it since we 
regarded it as negative in respect to trypanosomes, and we 
had a number of good preparations from owl 8. The one 
smear of bone-marrow made from owl 7 had, unfortunately, 
very little on it, and was not much use ; hence, and in view 
of our experience with owl 19, presently to be described, we 
cannot feel at all sure that trypanosomes were not present in 
owl 7, perhaps scanty in number. 
Owl 11 had a good infection with Leucocytozoon, and 
Halteridium was also present; the latter form was exces- 
sively rare, however, only a few flagellating gametocytes being 
seen in the course of many living examinations, and the para- 
sites beingextremely difficult to find in permanent preparations. 
No trypanosomes were found in the bone-marrow of this 
bird. On the other hand, in both owls 13 and 14, the next 
birds obtained which had a good (or fairly good) infection 
with Halteridium, and in which Leucocytozoon also 
occurred, trypanosomes were found after death without much 
difficulty, as in the case of owl 8. Owl 19 also had a good 
infection with Hal t er idi um, and when this bird died later on 
it was expected that trypanosomes would be found in it, as in 
the others; but in spite of very careful searching of fresh 
preparations for a period of two hours no indications whatever 
of trypanosomes were seen ; a colleague, Dr. Reichenow, who 
was then working at Rovigno, also kindly examined a pre- 
paration without finding anything. Hence it was thought that 
in this case the Halteridium and the trypanosome of the owl 
had been definitely separated from one another, and' that this 
was a case of infection with the former parasite only. How- 
ever, good preparations from the organs of this bird were made 
for the sake of the Halteridium and Leucocytozoon, and 
in the systematic search of these undertaken since returning 
home, three small trypanosomes have been found in four 
