C. M. Wen YON 
297 
house-flies, they were fed on the sore one or more times and dissected 
at varying intervals after feeding. The possibility of the occurrence of 
a natural flagellate infection has to be remembered in these experiments, 
which were all made with flies caught about the house. 
1. In every fly dissected immediately after feeding on the sore or 
on the exudate or scrapings from this, Leishman-Donovan bodies were 
found. 
2. Flies fed in the .=ame manner and dissected five hours after 
feeding gave negative results. The parasites had disappeared. In some 
of these flies natural flagellates were found, but there was no possibility 
of mistaking these for the sore parasites. The fact that natural flagellates 
occurred in a few, does not affect the result which was the disappearance 
of the parasites in such a short time in the large number of flies 
employed. 
3. Batches of flies were fed on the .sore daily, and a certain number 
dissected each day. In every case twenty-four hours had elapsed since 
the last feed when the dissection was made. In this way flies dissected 
had had one to ten feeds from the sore. Those that had had ten feeds 
must have taken up enormous numbers of parasites, but in spite of this 
no evidence could be obtained that any development had taken place. 
The maximum number of feeds any single fly had was ten, and the dis¬ 
section was made eleven days after the first feed. The repeated oc¬ 
currence of the natural flagellates in the experimental flies might tend 
to obscure the result, but the proportion of infected flies amongst those 
that had fed on the sore, was not greater than those fed in other ways. 
To test this latter point control flies were fed daily on human blood 
from an uninfected person. The different batches of flies wei-e not all 
kept at the same temperature. Some were kept in the laboratory where 
the temperature was high and frequently attained 80’-110° F. for 
the twenty-four hours. Others were kept in the Sirdarbs where the 
temperature did not rise much above 80° F., and others were kept in 
small porous earthenware jars covered with mosquito netting, and 
standing in plates of water. The water soaked up the sides of the 
porous pots, and by evaporation the temperature was considerably 
lowered and registered inside the pot from 70° to 75° F. In all cases 
the results were the same and no evidence of development was dis¬ 
covered. 
In some series of flies it was found that the number of individuals 
with a flagellate infection w^s greater amongst those that had not fed 
on the sore. For instance, twenty flies were fed daily for ten days on 
