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The cyanide used in all three methods is so dangerous to human and animal 
life that it cannot be recommended for general museum practice in view 
of the availability of other less dangerous and equally effective chemicals. 
It should be borne in mind that this gas is lighter than air and necessitates 
suitable arrangements for ventilating the room or fumigator in which it 
has been used. 
Advantages. Absolute toxicity, n on-injurious to specimens unless 
they are splashed with the sulphuric acid, non-explosive, non-inflammable, 
fairly inexpensive. 
Disadvantages. Extremely poisonous to human beings and all other 
forms of animal life; somewhat difficult of application, requiring the 
services of a competent, experienced operator. Its use should never be 
attempted by an amateur. 
Fumigator 
A satisfactory type of fumigator which can be used with the mixture 
of ethylene dichloride and carbon tetrachloride, with carbon disulphide 
or with carbon tetrachloride, is a large box measuring about 6 feet by 3 by 
3, which is lined with sheet metal. The joints, laps, and corners must 
be carefully soldered so that the gas can not leak out of the box. The lid 
is also sheeted in metal and is supported on the edges of the box, which are 
grooved all round to take half-inch rubber tubing. The top is held to the 
sides of the box with window catches, so arranged that the lid, which may 
be lifted right off to put specimens in the fumigator, is forced tightly 
against the rubber tubing, thus making a gas-proof joint. The tubing 
should be renewed at intervals, as it will harden after the lapse of a year 
or two. Two short metal pipes, fitted with screw caps, pass through the 
lid of the box, one near each end, so that the liquid may be poured in after 
the specimens have been inserted and the lid clamped down. These tubes 
lead into two shallow pans (such as photographic developing trays) which 
receive the fumigant, and their capacity should be determined in advance 
so that the correct quantity of liquid to use will be known. 
The fumigator should be thoroughly cleaned after use, and it is well 
to make a practice of leaving specimens exposed to the gas for at least two 
days, and then fumigating them again after the lapse of two or three weeks. 
HEAT AND COLD 
Clothes moths and other insect pests can maintain existence only 
between certain limits of temperature, and may be exterminated by carry- 
ing the materials in which they are found beyond these limits. In many 
parts of Canada advantage may be taken of below zero weather to destroy 
insects by exposing infected specimens to a temperature below zero Fahren- 
heit for a period of at least 24 hours. Temperatures above zero are much 
less effective; thus, some clothes moth larvae were found to be still living 
after three weeks’ exposure to a temperature of ten degrees above zero. 
This same method may at times be employed to rid storage rooms and 
even houses of pests, after emptying all water pipes and removing anything 
that might be damaged by freezing. 
