454 
Combating Lousiness 
are arranged to permit of a continuous inflow of clean hot air which 
serves to dry damp effects, the damp-laden air escapes at ( d ), and fresh 
air, aspirated into the apparatus at (/), passes through the heating 
shaft and thence to the blower and chamber. The size and power of the 
blower necessarily vary in accordance with the work to be performed. 
Fig. 13, which is published by Miessner and Lange without explana¬ 
tion, illustrates a large apparatus in which the clothes, hung on racks, 
are run in and out on rails at the top. Although no doubt very efficient 
for louse destruction, the Yondran apparatus must be very costly. Whilst 
it appears suited for permanent installations, there is no doubt that 
simple and inexpensive hot-air huts heated by stoves, radiators or coke- 
braziers will answer equally well for military purposes. As pointed out 
in the passage I have italicized (see p. 451) the mode of packing the 
apparatus is important in respect to its efficiency. 
2. Moist Heat. 
(a) The Immersion of Effects in Hot Water. 
The experiments recorded on p. 433 show that («) scalding infested 
articles, or (6) dipping them into water at 70° C. for a minute or two, or 
(c) exposing them for 10 minutes at 55° C. will kill all the vermin they 
contain. Whilst granting Peacock’s contention (MS. i. 1918) that it is 
best to dip underclothes in boiling water because most people have no 
thermometers wherewith to determine the temperature but understand 
what “boiling water” means, it appears worth noting that a lower 
temperature suffices for the purpose because of the injurious effect of 
high temperatures in causing shrinkage of some fabrics. There is no 
object in adding cresol or soap to the hot water unless the latter is 
employed for the cleansing of soiled effects. 
( b ) The Steam Jet. 
From what has been stated on p. 434 the steam jet, when available, 
can be used effectively for killing lice on clothing or in disinfesting railway 
carriages and the floors of premises, etc., in place of insecticide solutions. 
(c) Steam Disinfestation. 
Improvised Apparatus. 
The relative advantages of hot-air and steam disinfestation will be 
presently discussed (see p. 479). AYe may commence by considering the 
different types of steam disinfectors that have been used, beginning with 
the simpler improvised kinds that have been found effective in practice. 
