212 BE. A. MINGHIN. 
blood, development was not obtained, but in flies fed on sickly 
animals with few trypanosomes in their blood, a vigorous 
growth and development of the trypanosomes resulted. 
Stuhlmann (41) has published a preliminary account of 
the results obtained by himself and Kudicke. These 
investigators worked both with freshly-caught flies and 
with flies bred in captivity. The latter were found to 
become most easily infected if fed on the infected animal for 
their first meal after being hatched from the pupa; in 80-90 
per cent. of the flies so treated, after a short time (2-4 days) 
the intestine (Hinterdarm) became full of trypanosomes, 
indifferent forms showing many division-stages. Stuhlmann’s — 
figures of sections show the trypanosomes present in enormous 
numbers, similar, in my experience, to an infection with T. 
grayi. From the intestine the infection was found to spread 
forwards into the stomach (Mitteldarm), but rarely extended 
further forward than this region, unless the flies were re-fed 
on healthy animals; when that was done the infection could 
be traced forward as far as the proventriculus. Infection of 
the proboscis was not produced in artificially infected flies, but 
was found in a small percentage of those naturally infected. 
It was found, moreover, that in artifically infected flies the 
infection produced in the intestine often gradually died out, 
and only about 10 per cent. of the experimental flies obtained 
an infection of the stomach and thoracic intestine; thus the 
percentage of flies that became thoroughly infected in the 
laboratory came to about the same as the percentage of flies 
found infected in nature. The authors figure forms which 
resemble to a certain extent some forms of T. grayi, but 
which are characterised by a small round kinetonucleus, 
They distinguish indifferent forms, long forms, and small 
forms. ‘The long forms are found in the proventriculus and 
cesophagus, rarely in the proboscis. The small forms are seen, 
from the figure given (loc. cit., fig. 158 a), to be very similar 
to the small forms of T’. grayi with n in front of N (fig. 182) 
except for the characteristic difference of the kinetonucleus. 
It is remarkable, therefore, that the authors should find the 
