104 
body of the fly may depend to some extent on the period of 
time elapsing between their development into the final stage 
and their escape or removal from the proboscis. 
Observations on the worm embryos suggest that these 
normally do not leave the egg-membrane, and their róle.is a 
passive one. ; 
N 
Preliminary experiments carried out in 1916 and 1917 
heads and proboscides of flies, and placed in a sealed pipette 
held vertically and filled with normal saline solution. When 
hyperplasia of the fixed cells, and the formation of multi- 
nucleated cells. No necrotic areas were produced. . : 
It was conceivable that keeping the larvae in saline 
prevented the occurrence of necrosis. In later experimen ® 
larvae were either allowed to escape from the proboscis due 
into the tissues of experimental animals, or a mixture of equ 
parts of normal serum and saline was used as a medium 9 
inoculation. The larvae were only allowed to remain in this 
fluid for about thirty minutes before being used. f 
The preliminary experiments made in the latter p id 
1916 and the early part of 1917 were seven in number, 4? 
animal .was the one designated as pony in the 7" 
experiments outlined below. These preliminary experimen 
. Were made as follows: — 
_ Experiments with Habronéma muscae:— 
2 i » D) Embryos of H. muscae were placed in moist sawdust and | 
ss, Q1Be mass applied to the shaved skin of a horse. — 
RU AM (2) = eee from the proboscis of a fly were placed on in 
NIE HM s Ne of. scii itae the site being moisten 
