INSECTS AFFECTING HEALTH OF MAN OR ANIMALS. ri 
controlled. Furthermore, this species has been proved to be the 
carrier of typhus fever, which is prevalent in a considerable portion 
of Mexico. Moreover, its bites are very uritating and sometimes 
become infected, especially when the infested person scratches. This 
species is found on the body only during its short feeding periods. 
At other times it is to be found in the clothing. All articles of cloth- 
ing, even the shoes and headgear, become infested, particularly when 
the lice secrete themselves in seams, folds, and crevices, and it is 
there that they deposit their eggs. Beds and bedding become in- 
fested with the body lice, and where they have multiplied excessively 
even the crevices of walls, floors, and ceilings, the furniture, carpets, 
and hangings are inhabited by them. 
The head louse infests particularly the hairs of the head. The eggs 
are glued to the hairs some distance from the scalp, and this justifies 
the ancient and simple method of control by clipping the hair very 
close. When this procedure does not result in complete riddance, a 
2 per cent solution of carbolic acid should be applied liberally. 
The crab louse infests particularly the pubic region, although it 
may spread to the chest and other hairy parts of the body, particu- 
larly in heavy infestations and in very hairy individuals. This species 
attaches itself very firmly to the hairs, but does not ordinarily occur 
— inthe clothing. On this account it does not spread as readily as the 
body louse, and it is easily controlled. A single thorough application 
of mercurial ointment, popularly called blue ointment, is usually 
effective. 
fF 
Cy 
; 
#: 
f 
; 
t 
{ 
e& 
Experiments in detail and on a large scale, carried on among soldiers in billets and 
trenches, go to prove (1) that the soldier himself is the main source of infestation, 
(2) that the measures suggested below are of great benefit. 
(1) Whenever possible, and as regularly as possible, search the clothing thoroughly 
for both lice and the ‘“‘nits” or eggs. If you have discovered that the removal of the 
__ white patch which binds the seams at the fork of the trousers does not interfere with 
_ comfort, it is well to remove the patch. Special care during the searching for the 
lice and eggs should be paid to this region. 
(2) The great source of danger is the presence of eggs on the clothing. These hatch 
in about a week. It is necessary, therefore, that the trousers should be ironed and 
brushed at least once a week. 
(3) Against the lice themselves, whenever it is found necessary, use. the remedies 
recommended. Powders, as a rule, should not be used at the fork, but down the 
shirt and trousers. Care should be taken to see that any powder which falls from the 
shirt to the fork should be small in amount, as too much is liable to cause smarting. 
_ Ifyour stock of ointment (see note below) and powder is exhausted, apply to the man 
_ in your unit who is responsible for these preparations. 
4 (4) Just previous to going to the trenches be careful to treat the clothing and body 
as directed. 
(5) Use the preparations about every four days. Experiments in the trenches have 
shown this to give the best results. 
(6) See that any material, blankets, empty sandbags, etc., which may be present 
toincrease the comfort of the dug-out or billet, are treated with the powder preparation. 
_ (7) Take advantage of all the facilities offered at the baths. 
