BY DR. A. JEFFERIS TURNER, M.D. LOND., D.P.H. CAMB. 101 
If we want to keep down the numbers of the fly, we 
must keep down the food material of its larva. We 
must do our own sanitation, and not let the fly 
larve do it for us. This is the root of the matter. There 
are certain palliatives, which are, however, not to be 
neglected, for I am not so sanguine as to expect to see 
the domestic fly banished from our midst ; we must expect 
to see some, even though in reduced numbers. It is possible 
to exclude flies from dwellings by fly-proof doors and windows 
but at the expense of diminished light and air. We should 
at least exclude them from our food, and more particularly 
keep them out of the milk-jug. A small piece of mosquito- 
net, weighted round the edge with glass beads is sufficient 
for the purpose. All fecal matters should be well-covered 
from flies, and the further addition of some disinfectant 
whose odour is disagreeable to the fly is a precaution not 
to be despised. In country districts where cowdung and 
horsedung are abundant, and inhabitants are few, palliative 
measures are, I fear, all that can be adopted. 
While this method of conveyance of disease-germs 
by flies and other insects is probably more common than 
is generally suspected, there is a second class of instances 
in which the insect plays a more important role. In these 
the disease-germ is conveyed, not by accidental contact 
with the outer surface of the insect, but in its interior, and 
is inoculated into the body of the affected animal by the 
bite of the insect. Of these many examples are now known, 
from which I will select a few of those which have been most 
thoroughly investigated in connection with the human 
subject. 
MOSQUITOS AND FILARIA. 
Considerations of time will prevent me from more than 
a passing reference to the propagation of filarial disease by 
the mosquito. It is of interest, as being the first disease 
in man, which was proved to be conveyed exclusively 
by the bite of an insect, in this instance the common House 
Mosquito, Culex fatigans. The adult worm, which was 
first discovered by a member of this Society, the late Dr. 
Joseph Bancroft, inhabits the lymph vessels of man. 
Its embryos are discharged in myriads and through the 
