Typhus prevention equipment: the Lelean sack disinfestor, used to disinfest clothing and kill lice carrying typhus. Photograph, 1900/1920 (?).

"Lelean has recently enunciated a new principle in disinfection which has an important bearing on disinfestation. When steam is evolved, or blown in, at the bottom of the chamber containing the garments, it passes between them to the top, which it fills up first. The result of this is that pockets of air are imprisoned in the folds of the garments and these pockets prevent the even heating of the articles. He therefore advises that the steam should be blown in at the top as it will thus drive the heavier air down before it and prevent the formation of these air pockets. He has devised a system, a unit of which consists of four steam-proof bags, the mouths of which are provided with running nooses. When the bags are loaded they are inverted and lashed to the central chimney. By means of flexible pipes steam is led from the boilers to what are now the tops of the bags, and escapes below to pass between the stones into the flue and so up the central chimney (see figs. 160 and 161). This disinfestor is the most portable one yet devised and is stated to be both rapid in action and very efficient. The principle involved recalls that well known in disinfection with pressure steam; namely, that articles such as roller bandages are more quickly and certainly sterilized if the chamber is exhausted before the steam is admitted. Fig. 161. Lelean's sack disinfestor. One 50 lb. unit in process of transport. The boiler, the six fire bars and the sheet of perforated corrugated iron used to support the stones are rolled up inside the sack."-- Byam and Archibald, loc. cit.