90 



Bacot (A. W.)- The Louse Problem. — Separate, dated 23rd February 

 1917, from Proc. Roy. Soc. Medicine, London, 1917, x, (Sect, of 

 Epidemiology and State Medicine), pp. 61-94. [Received 19th 

 May 1917.] 



The experimental part of this paper has already been noticed [see 

 this Review, Ser. B, v, p. 69]. Preventive measures for the protection 

 of troops at the front naturally fall into two groups, the establishment 

 of baths, wash-houses and laundries for the treatment of discarded 

 clothing, and the issue of insecticides, including c^uick-acting remedies 

 for use in emergencies and more stable slow-acting ones for continuous 

 use. The question of economy of fuel and time should not be over- 

 looked in the treatment of clothing ; for example, dry heat at 130° F. 

 applied for 30 minutes will destroy all lice and their eggs, as well as the 

 active females of Sarcoptes causing itch, thus obviating the waste of 

 time and additional fuel required to dry the garment after the appli- 

 cation of hot water or steam. The ironing of the seams of tunics and 

 breeches is effective and convenient, though economy of labour and 

 greater efficiency could be obtained by hanging the garments in a hot 

 room, or, better still, when speed and economy of fuel are important 

 factors, by passing them through tubular ovens on travelling hangers. 

 Similarly in the cleansing of midergarments and bedding, eggs are 

 destroyed by the action of boiling water in half minute, the addition 

 of chemicals being thus superfluous. On the other hand, if insects 

 and eggs can be killed more conveniently or cheaply by chemicals, the 

 process of boiling in addition is wasteful. 



Insecticides may act either by contact or vapour, but for practical 

 purposes in this connection contact remedies only are efficacious. 

 The essential point in their use is a knowledge of the best method of 

 application. Probably the worst and most wasteful is that of direct 

 application to the skin. In the case of rapidly dissipated oils, they 

 must be evenly distributed in minute quantities by means of a medium 

 which retards their action and for this purpose the best substance is 

 soap, which may be used as a paste or as a watery emulsion and aids 

 in the final cleansing of the garment. The best remedy, which remains 

 efiective for nearly a week and is inexpensive, consists of crude carbolic 

 acid emulsified with soft soap in the proportion of 45-50 per cent. 

 soap to 55-50 per cent, of carbolic, sufficient heat being used to 

 melt the soap thoroughly. The best strength for impregnating 

 garments is from 5-10 per cent, according to climate or the time of 

 year, as its action depends on the amount of perspiration. An average- 

 sized shirt takes up 1,000 c.c. of fluid and retains 500-600 c.c. after 

 syringing, and costs at pre-war rates | to 1 penny according to the 

 strength of the solution. The comparative slowness of its action is its 

 only drawback. The most efficient, cheap, and quick-acting remedy 

 is naphthaline, which is soluble to the extent of 40 per cent, in benzine, 

 of 5-10 per cent, in methylated spirit and of 15 per cent, in paraffin. 

 With the application of heat, it can be dissolved in oil or oily fluids, 

 and subsequently made into a watery emulsion for the purpose of 

 impregnating clothing. 



' The paper concludes with a simimary of insecticides for the treatment 

 of clothing and for the destruction of lice and their eggs. 



