192 Drs Fantham and Porter, On Induced 
when the insects contained many bacteria, the protozoal flagellates 
usually disappeared. Further, some digestion experiments per- 
formed by us have shown that many bacteria introduced into the 
digestive fluids of the bird’s stomach are destroyed by the same, 
while the flagellates are but little affected. This is not surprising, 
since certain protozoal infections of man are known to flourish 
in an acid medium, and are combated by the use of alkaline 
substances. 
The Morphology of the Parasites in the Insect and 
Avan Hosts. 
The morphology. of Herpetomonas jaculum and H. culicis in 
the insect and avian hosts shows little difference. Where the 
infection of the birds was of the chronic type, the non-flagellate, 
leishmaniform bodies were more numerous 1n organ smears, while 
in the acute cases the flagellate forms preponderated. We would 
point out that, while such was the case in these experiments of 
ours, we do not consider that any generalisation can yet be made 
therefrom. However, it may be noted that Monge (1914), dealing 
with the flagellate stages of Leishmania tropica in man in Peru, © 
states that the presence of such flagellate stages may be an 
indication of increased virulence. 
Herpetomonas jaculum, as found in our experimentally infected 
birds, showed non-flagellate and flagellate forms in various stages 
of growth and division. The non-flagellate parasites were from 
4 to 66 long by 2 to 54 broad. They were oval, the nucleus. 
being usually homogeneous but occasionally showing a karyosome, 
the blepharoplast occupying various positions in the body, as it 
does in the parasite as found in the insect. 
Full grown flagellates were comparatively rare in the birds. 
They were morphologically like those in the insect host, but the 
maximum size, as In previous experiments, was not quite attained. 
Herpetomonas culicis in the Culex, sparrow and martin had 
the same appearance. The non-flagellate forms were oval or 
pyziform, measuring 4w to 6m by 24 to 4yu. Non-flagellates in 
various stages of division occurred. The flagellates were elongate, 
their body length varying from lly to 16m, and their breadth 
from ld to 36u. The nucleus was usually granular, only 
occasionally karyosomatic. The blepharoplast was always con- 
spicuous and varied from round to barlike. Multiplication of 
non-flagellate and flagellate forms by binary, longitudinal division 
occurred, 
