474 
Combating Lousiness 
from any available source. The current steam at atmospheric pressure 
(controlled by a stand pipe) raises the temperature of the inner chamber 
to 100° C. Steam may be allowed to enter the inner chamber or not, as 
required, by means of a three-way cock', the steam escaping into a flue. 
The apparatus is stated to heat up to 100° C. in 10 minutes. 
The “ Ibis ” Steam, jacketed Disinfector (Isaac Braithwaite and Son, 
Ltd, Engineers, Kendal and London) conforms in general plan to those pre¬ 
viously mentioned and is loaded, etc. in a similar manner. The chamber is 
first heated to57-60°C. (135-140°F.) by means of steam at 10 lbs. pressure 
admitted to the jacket; a partial vacuum (15-20 inches) is then produced 
in the chamber and steam is afterwards allowed to enter at 7 \ lbs. pressure. 
The exposure lasts about 20 minutes, the temperature attained being 
107-110° C. (225-230° F.). Steam is then cut off from the chamber and 
the drying process commences, a current of hot air being admitted into 
the chamber below and traversing its interior (PI. XIII, Fig. 11). 
In all machines in which a cradle is employed for holding the effects 
to be treated, there is a general tendency for the articles to become more 
tightly packed when they are steamed. Peacock ( loc. cit.), who notes 
this in connection with the horse-drawn Thresh machine, states that he 
sought to counteract the tendency by putting an old perforated iron 
bucket in the bottom of the cradle, above the steam baffle in the centre 
of the floor, or by placing two-inch wooden battens lengthwise across the 
top of the cradle. 
The Number of Articles with which a Disinfector should be 
charged, Working Capacity, etc. 
It has already been stated that disinfestation, either by hot air or 
steam, may fail utterly if the chamber is overcharged, it being essential 
that the effects should be packed in loosely or preferably hung up with 
interspaces between them thus permitting the hot air to drive out the 
cold or the steam to drive out the air, otherwise the process has to be 
unduly prolonged. It is especially important in the practice of military 
disinfestation to determine what is the standard load for a particular 
disinfector so that the operator can foretell within narrow limits how 
long it will take to treat the effects adequately at a given temperature 
allowing for variations outside. Punctuality and measure in all things 
are of great moment in military affairs. 
