TRYPANOSOMES IN TSETSE-FLIES AND OTHER DIPTERA. 161 
some infections ; after which I shall give a bare record, in 
chronological sequence, of my experiments and observations. 
The latter part is intended rather for reference, and to avoid 
the possible danger of omitting something which in the 
present state of our knowledge seems immaterial, but which 
may. prové in the future of greater importance. 
Before proceeding to describe my results it may be per- 
mitted to me to enter upon a brief personal explanation of 
my relation to the work of the Commission; after which I 
shall say a few words upon the methods of investigation 
employed. 
When I came to Entebbe, at the beginning of April, 1905, 
my two colleagues, Lieutenant A. C. H. Gray, R.A.M.C., and 
the late Lieutenant F. M. G. Tulloch, R.A.M.C., were already 
at work upon the subject which I was sent out to investigate, 
and had discovered some facts of importance. In particular, 
they had found and studied the vast swarms of trypanosomes 
which are frequently found in the alimentary canal of freshly- 
caught tsetse-flies. Neither my colleagues nor myself had 
at that time any doubt but that these “ wild” trypanosomes 
represented stages of T. gambiense. Since it was arranged 
that Gray and Tulloch were to work in connection with me, 
and since I did not wish to absorb, as it were, into our joint 
work anything of which the credit belonged to them inde- 
pendently, I requested them to write up and publish all 
that they had found before my arrival, so that we could start 
our collaboration on a clear footing. This they did, and the 
result was the memoir (17) published in the ‘Sleeping Sick- 
ness Reports,’ a memoir in which Tulloch’s excellent drawings 
- were done scanty justice in the reproduction. While Gray 
and Tulloch were engaged upon this report I commenced 
a systematic investigation of the anatomy of Glossina 
palpalis, then an untrodden field of study, upon which a 
preliminary report was published in the ‘ Proceedings of the 
Royal Society’ (27). One of the first results of my dissection 
of the fly was to show that the structure termed by Gray and 
Tulloch in their memoir “ the salivary gland ” was really the 
