75 
kept stirred while a skin is being dipped, will do very well. Sodium 
arsenite diluted with water is better, as it penetrates the skin and is 
soluble. The sodium arsenite solution is made as follows: 
Arsenic trioxide (white arsenic, AS 2 O 3 ) . . I pound 
Carbonate of soda (washing soda, Na 2 C 03 ) \ “ 
Water 1 quart 
Boil for an hour, stirring occasionally (Rowley, 1925). 
If the skin softens after dipping, it should be re-salted and thor- 
oughly dried out again. 
This formula may be used to poison the exterior of mounted speci- 
mens that are infected with moths or dermestes, after spraying or paint- 
ing the hair with gasoline (applied outdoors). Poison preparations on 
the inside of the skin help to keep out insect pests and protect the skin 
itself, but unfortunately there is no substance yet known that will work 
through the skin and positively protect the hair or feathers. The old 
method of spraying or brushing the outside of a specimen with corrosive 
sublimate or bichloride of mercury (HgCl 2 ) dissolved in alcohol is 
effective enough as far as insects are concerned, but is extremely danger- 
ous and is not recommended, as persons handling the specimen later are 
very apt to suffer from mercuric poisoning. In dusting such specimens the 
invisible bichloride powder may be inhaled or absorbed by the skin. 
The development of the use of DDT (dichloro-diphenyl-trichloro- 
ethane) solution about 1944 for control of various insect pests, including 
moths and beetles which damage or ruin skins, furs, and woollen fabrics, 
has been very successful and may supersede some of the older insecticides 
and repellents. It may be dusted on as a powder, or sprayed in a solvent 
or emulsion. C. R. Twinn {in litt., 1947) cites experiments by Jensen 
and Holdaway (1946) who conducted experiments to determine the com- 
parative efficiency of various materials in protecting rabbit hides from 
larvae and adults of two species of Dermestes. They found DDT to be 
outstandingly superior to all others. When applied in spray and dust 
form a single treatment gave excellent protection for at least 371 days, and 
hides treated while fresh were as well protected for extended periods as 
were hides treated after they had been dried. Two forms of DDT were 
used, namely, dusts and sprays. He recommends spraying with 5 per cent 
DDT in deodorized kerosene, provided that a light application of kerosene 
would not harm the specimens. DDT itself has been used successfully as a 
moth-proofing agent on various kinds of textiles. For this purpose it is 
efficient against clothes moths as well as Dermestid beetles. 
Conditions in Canada are such that if fresh specimens are carefully 
watched in the field and are clean when shipped, hair poisoning is sel- 
dom necessary, as the specimens can be treated in the museum before 
serious damage is incurred. If a large skin, or mounted mammal or head, 
has been treated with hair poison, it should be marked “Poisoned with 
for the benefit of persons who have to handle it afterwards. 
SPEED AND EFFICIENCY IN TECHNIQUE 
Getting into the haunts of big game at the present time in North 
America usually involves long travel and heavy expense, and frequently 
when the game is stalked and killed the end of the day is near and time 
