DR. S. H. LONG ON THE MOSQUITO-MALARIA THEORY. 201 
should bo of such a thickness that it is impossible for the insect 
to bite through it. The parts usually bitten when out-of-doors are 
the ankles, which are generally covered only by a single thickness 
of sock. By the use of double socks, Mosquito boots and puttees, 
the ankles may be completely protected. When possible, it is 
advisable not to be out in the open air between the hours of sunset 
and sunrise, for it is between these hours that the insects come out 
from their hiding-places in the hopes of being able to satisfy their 
hunger by the blood of man. Sleeping in the open air, unless 
thoroughly protected by Mosquito curtains, should always be 
avoided. If it should be necessary to be out at night time the 
hands should bo protected by gloves attached to the sleeves, and 
the head and face by some form of covering, such as a cowl. All 
windows and doors of the house should be carefully protected by 
Mosquito curtains, which are made either of muslin, or, better, of 
wire. A light should never be allowed in the sleeping compartment 
when the window is open, and before going to bed a thorough 
search should be made for any stray insect that may have inadvert- 
ently gained entry during the day. 
I would here like to add what may not be generally known, 
that, besides the Mosquito, several other insects probably play no 
unimportant part in the spread of disease. 
As has been pointed out by Nuttall, it appears that the natural 
tendency to crush a tly that is biting one is especially fraught with 
danger, owing to its virulent contents being rubbed into the 
wounded skin ; for it would seem that in many cases, where the 
infection has been attributed to the bite, it is the crushing of the 
insect that has led to infection. The ordinary House-fly ( Musea 
domestica ) has been proved to carry about and deposit the bacilli 
of anthrax in their excreta. It has also been proved to be able to 
carry the infection of plague, in the dissemination of which disease 
Ants and Fleas also probably play an important rule. Bugs and 
Fleas have so far been proved not to occupy any very important 
part in the spread of disease. 
House-flies play an important role in the diffusion of cholera, 
and probably also of typhoid fever. 
With regard to the extermination from a community of the 
parasite of infection in man, the two chief methods that have 
been adopted towards this end are : — 
(1) That which was successfully employed in New Guinea by 
