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Legroux (R.). Sur la destuction des poux. [On the destruction of 

 Uce.]— Bull. Soc. Path. Exot., Paris, viii, no. 7, 1915. pp. 470-173. 



Exanthematous typhus is transmitted by the bites of lice ; Pediculus 

 Imnumus {vestimenli) and P. capitis are the active agents ; Phthirius 

 ■pubis {i)iguinalis) does not appear to be capable of carrying the infection. 

 The author has made experiments with volatile matters derived from 

 coal tar and others, with a view to finding something which would 

 rapidly kill lice at ordinary external and body temperatures of 60° F. 

 and 90° F. The experiments were made on lice 1 hour after feeding ; 

 in captivity one meal in 24 hours sufficed, but breeding cannot be kept 

 up on animals and the lice must be allowed to bite man. A cupping 

 glass is a convenient apparatus for feeding, as from 50 to 200 lice may 

 be put into one glass and turned on to the upper part of the 

 fore arm ; in from 5 to 10 minutes the louse is gorged and releases 

 its hold, and there is no difficulty in getting it back into the glass. The 

 lice should be kept, when not feeding, at 60° F. to 65° F. in a Petri 

 dish filled with small strips of tissue paper 6 or 7 centimetres long and 

 1 centimetre wide ; they creep between the strips and lay their eggs 

 on the rough edges ; oviposition generally takes place after feeding. 

 The best hatching temperature is from 76° F. to 82° F. ; it rarely 

 occurs between 61° F. and 65° F. The egg-stage lasts from 8 to 10 

 days, and 15 days after hatching, the louse is full grown ; it begins 

 to bite as soon as hatched. In each experiment, 4 adults, 2 young ones 

 of 6 or 7 days old and 4 well developed females were used. They were 

 put under the edge of a Koch bell-jar of 2,000 cc. capacity on strips of 

 tissue paper and at the opposite edge a drop of the liquid to be tested 

 was introduced, also on a strip of paper, and the bell-jar dropped over 

 it at once. As soon as the louse was observed to lie quite still on its 

 back with the feet retracted, the impregnated paper was withdrawn, 

 the edge wiped free of all traces of the substance used and the bell-jar 

 replaced ; in this way an attempt was made to reproduce natural 

 conditions as regards aeration in underclothing. Observations were 

 made as to the state of the lice every half hour for five hours and every 

 hour afterwards up to the twelfth, if the louse remained without motion 

 for 20 hours it was considered to be dead. The following substances 

 were tried ; anisol, methvlanisol, benzyle chloride, 10 per cent, 

 solution of naphthaline in alcohol and the following essential oils : 

 lemon grass {Andropogon citratus), eucalyptus, pennyroyal {Mentha 

 pulegiuni), sage {Salvia officinalis) and oil of cloves. The results are 

 recorded in a table, and considering efficiency, cost, etc., the mixture 

 which was most satisfactory, consisted of oils of lemon grass, penny- 

 royal and eucalyptus, 300 cc. of each, and powdered naphthaline, 

 100 grms. ; the oils evaporate in the order given. Pieces of cloth 

 or felt carrying from 6 to 8 drops of this mixture and fastened to the 

 underclothing at those spots where lice generally congregate, will 

 prevent breeding. To cleanse the clothing, ironing the seams and 

 other doubled or lined parts with a very hot iron is effective ; linings 

 should be wetted with five parts of the mixture in 100 parts of alcohol 

 and ironed at once. Military accoutrements should be put into a 

 barrel or other container Avhich can be closed almost hermetically and 

 exposed to the vapour of the mixture at a temperature of from 105"" to 

 112° F. ; 5 cc. per cubic metre is sufficient and the exposure should be 



(C223) Wt.P12/01. 1..500. 12.15. B.& F.Ltc!. Gp.11/3. a 



