ENTOMOLOGY

SANITARY ENTOMOLOGY4. Hot A.ir DelousingHot air was used very extensively for delousing the armies, especiallyon the eastern front. This system is not sterilizing, nor is it especiallydangerous to the garments except when allowed to get too hot. Stagnanthot air has less effect than fresh hot air. The garments must be hungloosely. Provision should.be made for circulating the air so that all ofthe clothes will receive the necessary amount of heat, which is 131 0 F.(55 0 C.) for 30 minutes, or 140 0 F. (60 0 C.) for 15 minutes. The heatchamber may be a portable box such as a fireless cooker; a room heatedby steam pipes or hot air; a sad hut; a steel autoclave; or an improvisedoven. Very high heat must not be used on dry garments as it will disintegratethe fibers of woolens and cause shrinkage.5. F'I.II1nigationWhen fumigation chambers are available and the clothing is needed forimmediate wear, this is one of the quickest means of delousing. Thefumiga tion chamber may he:ok. A room, 'With cracks tightly scaled, and ,vith vestibuled doors.A sign of warning should he posted and the door kept. locked during fumigations.Only persons understanding fumigation should he permittedaround, and they should wear gas masks.1:i. A chest or box is sufficient for carbon bisulphide or chlorpictin.c. A portable unit, such as an automobile with an air-tight chamber,and with hangers or shelves. The gas generator may be placed behindthe chauffeur's seat.d. A vacuum chamber as in steam sterilization. The same cylindermay be made available for either steam or gas.The fumigation may be either at normal atmospheric pressure orin a vacuum. When a room is to be fumigated one should see that thereare no persons in the building, as few buildings are constructed so thatI:he gas can not penetrate to other rooms.To fumigate an entire building, or a room, close tightly all openingsin building and seal up cracks with paper, unless the insects are inthe double walls, in which case seal the cracks on the outside. It maybe necessary, if the building is too loosely constructed, to increase dosagesor make a tarpaulin to cover the entire structure. Such measures shouldonly he taken in case the normal fumigation is unsuccessful. Any ofthe following methods are practicable. Entomologists prefer cyanidebut many army officials prefer sulphur.a. Sulphur corrodes metal, so aU movable metal should be taken outof the building. Sulphur fu~igation is described in Public Health Bull.