340 H. M. WOODCOCK. 
The Halteridia being so numerous in this bird at that 
time, I confess I expected, from Schaudinn’s account, to have 
little or no difficulty in finding various stages in the transition 
of the parasites from an active, trypaniform phase, to a 
resting, intra-cellular, Halteridium-phase and vice-versa 
—always supposing, that is, such a connection exists in this 
case. A general examination of the more likely slides, 
including smears from the bone-marrow, etc., showed no 
indications of such behaviour. Trypanosomes of any kind 
were very scarce as compared with the great number of 
Halteridia present, and the few individuals noticed were 
manifestly larger than the largest Halteridia. I was 
unable to do more than make a somewhat cursory examina- 
tion at the time, as I was very much occupied with the 
research in another direction; and owing to the pressure of 
other work subsequently, it was not until autumn that I was 
in a position to begin the laborious and time-consuming 
process of systematically searching these shdes. I am 
pleased to say this study has now yielded me some most 
interesting results, and further search would yield, I believe, 
more yet. As, however, I shall probably have to leave the 
work at this point for some time, I think it worth while to 
publish this note. I propose to state shortly those observa- 
tions made up to the present which bear upon the above 
question, and to consider briefly the meaning which, it seems 
to me, is to be attached to them. 
Fully-grown Halteridia of three types occur, male and 
female forms with the usual well-known distinguishing 
features, and a third type corresponding to the “ indifferent,” 
or non-sexual form of Schaudinn; the last-named type is 
distinguished from a female form by its much lighter staining 
cytoplasm, and from a male form by its compact, denser 
nucleus. This indifferent type is by far the least common of 
the three in these slides. Halteridia of all sizes, however, 
are to be found in the red blood-corpuscles, from very 
minute, oval or pear-shaped forms, 2m or less in diameter, 
up to the large adult individuals. Many different phases can 
