538 
Combating Lousiness 
Ref. 
No. 
morning (Lelean). Peacock refers to it as the best all round 
insecticide he has tested; he advises dusting 2 oz. upon the shirt 
and trousers every 4 days. From observations on 5 men, Peacock 
concludes that the effect of keeping off lice lasts 3-5 days; he 
describes it as useful in the trenches, a good killer and repellant 
but a poor expellant, meaning that it does not appear to drive out 
lice that are established on the person. He observed no ill effects 
on himself and 3 men after using it a week, except that it produced 
itching or smarting at the fork; it should therefore be used in 
moderate amount in this region or be replaced by an insecticide 
ointment. Peacock advocates dusting it on the outside of the under¬ 
clothes and not upon the skin. The essential agent in the mixture 
is naphthaline, but as Bacot has found its range of action limited 
it should be well distributed so as to exert its effect by contact. 
Expt 93: N.C.I. dusted on a man and acting overnight killed 
many lice. Expts 99-100: it killed lice but not nits on man. 
Expts 83-85: dusted on shirts it killed lice in 3 or more hours. 
Expts 314-316: it killed about as well as naphthaline but caused 
more enfeeblement among the lice. N.C.I. and commercial naph¬ 
thaline evaporate at about the same rate; there is no evident 
advantage in the admixture of creosote and iodoform. The naph¬ 
thaline alone suffices, acting quickly but only for a short time 
because of loss by evaporation. Its lethal power as a vapour only 
extends to a distance of 2-3 inches from the substance as Bacot 
has proved. 
429. Naphthaline (crude) with various admixtures. These preparations 
were subjected to tests as to their relative efficiency, on behalf of the 
War Office, by Bacot, using active stages of corporis as described 
on pp. 509 et seq. 
(a) With carbolic acid and Oxford grease. Expts 296-297: it 
killed all lice after 4| hrs on freshly impregnated cloth, but had no 
effect after an interval of 148 hrs. 
( b) With Oxford grease. Expts 288, 322: it killed 76-95 % of 
the lice in 4|-5 hrs at first but had no effect after an interval of 
24 hrs. 
(c) With Oxford powder. Expts 299, 301-303: the powder de¬ 
creases the efficiency of the mixture in proportion as the amount 
of naphthaline falls. 
(d) With Oxford grease and chlor-cresol. Expts 295, 326: lice 
