298 
Oriental Sore 
scrapings of the sore, and another twenty daily on citrated human blood, 
for the same length of time. The surviving flies (twelve and fourteen 
respectively) were dissected twenty-four hours after the last feed. In 
those that had fed upou the scrapmgs of the sore no trace of Herpeto- 
monas could be found, while in two of the control flies flagellates 
probably U. muscae doniesticae occurred. In such an experiment the 
natural fly infections did not affect the result. In other cases the 
findings were reversed, but in none was there any evidence of a develop¬ 
ment of the specific parasite of the sore. 
Examination of the faeces of infected flies was always negative. 
In carrying out these experiments the gut was removed to a slide and 
films made from the contents taken from the stomach and intestine. 
These films were stained with Giemsa’s stain and examined for 
parasites. 
The constant presence of large numbers of bacteria of various kinds 
in the intestine of the house-fly may account for the quick disappearance 
of the parasite when taken up. As in artificial cultures the sore para¬ 
sites do not develop, or only to a limited extent in the presence ot 
bacteria, so one is not surprised to find that no development takes place 
in the gut of the house-fly. 
As will be shown below in the artificial cultures in rabbits’ blood 
agar, the lierpetomonas resulting from the sore parasites may be 
extremely minute and merely little flagellate organisms of not more 
than 2 /r in diameter. Such minute forms would be extremely difficult 
to detect amongst the mixture of substances and bacteria one finds in 
the gut of such an omnivorous feeder as the house-fly. However, one 
would at least expect to find some larger forms as in the artificial 
cultures. House-flies were also allowed to feed on cultures of the sore 
parasites in rabbits’ blood agar. Results obtained were similar to those 
obtained by feeding the flies on the sore. The flagellates taken up very 
quickly degenerated and disappeared. 
Stomoxys. Numerous experiments were made with these flies 
which were caught for the purpose in the stable near the house. The 
flies occurred in greatest numbers at the early part of the summer. 
During the hottest season they were difficult to secure. The flies taken 
in the stable had in most cases already had a feed of blood from the horses, 
so they were starved for twenty-four hours after which time theyi’eadily 
fed on the sore. It was not so easy to discover the parasites of the sore 
in the stomachs of Stomoxys, even when dissected immediately after 
feeding as in the case of the house-fly. The difference in the method 
