438 
Combating Lousiness 
The essential points to have in mind are (a) that hot air penetrates 
rapidly into fabrics that are loosely hung and amongst which it can circulate, 
and ( b) that stagnant hot air penetrates very slowly into tightly packed 
fabrics. These rudimentary facts have long been established by com¬ 
parative experiments dating from the early days of disinfection, never¬ 
theless they are persistently ignored, the result being oft repeated 
failures in practical disinfection with hot air or steam at atmospheric 
pressure to which these remarks equally apply. 
Barrels or ordinary packing cases through which hot air circulates 
have served as fairly efficient louse destructors. In some cases the heat 
is made to emanate from a pipe traversing the disinfestation chamber 
from a flue beneath the floor. 
Fig. 2. Hot-air disinfesting box according to Rieck. (A) viewed in perspective when open. 
<B) longitudinal vertical section. Copied from the author’s figure which omits the 
ventilator opening at the top. 
Portable disinfesting box (see Fig. 2). This is a simple structure de¬ 
scribed by Rieck (1916, p. 1177) as follows: 
Description: 1-5 m. long, 1-4 m. high. 0-85 m. wide; back, sides and top made of 
two thicknesses of crossed board; pasteboard separates the boards on top; walls held 
together by removable wedges as figured. Door, with wooden handles, held in jdace 
by wedges. Floor made of wooden slats attached a little above lower edge of sides. 
A simple frame with cross bars slides on side slats running along top and serves to 
carry 15 or more uniforms. Thermometer and ventilator are added on top for 
regulating the temperature. These parts being assembled, proceed to dig a front pit 
of ca. T5cbm., continuous with a shallow trench. Lay three iron bars across trench 
a little below ground surface and rest a sheet non plate (2 x 0-7 m.) thereon, putting 
earth around edge of sheet for box to rest on. Erect chimney at end of fire trench. 
The box can be used in the open or elsewhere in a very short space 
of time. Even with the use of green wood, the author states that a 
