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few hours if pupils and home contacts are simultaneously treated 
and pupils can be allowed to attend school during the treatment 
period.— Trerob ley (595 ) . 
Phthlru8 pjtbis (L.), the crab louse 
Derris powder, either dry or as a saponified wash, was very ef- 
fective .--Spencer (556 ) * 
In Denmark a tinoture of derris was applied as a spray and with 
brushes to 20 persons infested with crab or pubic lioe. Baths of 
this tinoture were very effective against the adults and their eggs. 
— Haxthausen (273 ). 
All infestations of crab lice on soldiers were effectively treat- 
ed in two military camps in Ontario, by one application of an oint- 
ment containing derris extract at concentrations from 0.5 to 2.5 per- 
oant of rotenone.— Twinn and MacNay (608 ); McLaine (386 ). 
Derris is effective against this speoies, although the advisa- 
bility of a general recommendation for its use is questionable because 
of the irritation produced in a considerable percentage of individuals, 
especially when the material is used too freely.— Trembley ( 595 ) . 
Unidentified Lice 
Since nearly all lice on man and animals belong to Anoplura 
and Mallophaga, the unidentified lioe and miscellaneous information 
will be discussed here. 
In a review published in 1941 it was reported that derris and 
cube, diluted with inert dusts or powders, represent a common form 
of the newer flea and louse powders. There are also products on the 
market which are mixtures of rotenone dusts with pyrethrum. Although 
there has been a trend toward the wider use of rotenone in flea and 
louse powders in the United States in recent years, powdered derris 
root was used in these preparations in England over 20 years ago be- 
cause its efficacy against these inseots was recognieed then. Most 
of the products are recommended also for control of lice, dog ticks, 
sticktites, etc., as well as fleas. Use on the human body to con- 
trol chiggers, and head, body, and crab lice is also commonly sug- 
gested. The problem of controlling lioe on canaries is rather unique. 
Powders made with rotenone and a talcum base give the canaries 
pneumonia, and the only product which an be used safely is straight 
pyrethrum powder. —Anonymous (5). 
