ON THE TRYPANOSOME OF THE LITTLE OWL. 
165 
a suggestion, which is, however, nothing more than a 
suggestion. We think it is not at all impossible that there 
may be some intra-cellular phase of trypanosome, perhaps even 
occurring in a red blood-corpuscle, still to be definitely 
ascertained. As was discussed in the preceding memoir with 
reference to the recent work of Chagas (2) and Hartmann 
( 5 ), it is reasonable to suppose that a schizogonous process of 
multiplication occurs in the life-history of these Avian trypano- 
somes, by which the small forms are developed from large, 
massive individuals. And it is quite possible that the 
immediate products of schizogony, which may be assumed to 
be small elements, pass for a time into the red cells before being 
liberated as small, active trypanosomes; such intra-cellular 
phases would most likely be found, we think, to be quite 
independent of the Halteridia, and might not possess pigment. 
In the scheme drawn up on p. 176, showing the relation between 
the different phases of the trypanosome, as found in the owl, 
we have indicated the position which this hypothetical intra- 
cellular form would occupy. 
In this connection reference may perhaps be made to a 
remarkable passage in Zupitza’s account of Avian trypano- 
somes ( 19 ). Zupitza states that in blood taken from a 
wounded “ Haarvogel” (“ Bulbul ”), in which both trypano- 
somes and Halteridia were present, he observed two or three 
red blood-corpuscles which were undergoing a strange 
spontaneous movement, turning over now in one direction, 
now in another. Further wave-like swellings of the mem- 
brane or envelope of the corpuscle were noticed. According 
to Zupitza careful examination of these phenomena showed 
that they were due to a small, slender trypanosome inside the 
corpuscle, which coursed rapidly through the cytoplasm, 
around the nucleus, first in one sense and then in the opposite 
one. Apparently the trypanosome was trying to bore a way 
out through the envelope of the cell, but'so long as Zupitza 
was able to watch it it was unsuccessful. We shall have to 
criticise Zupitza’s paper in many respects, but we feel quite 
unable to offer any comment upon this wonderful description ; 
