10 
or in a surgeon’s artery-clip forceps. “Used” razor blades generally have a 
keener edge than the ordinary run of scalpels, and to avoid infection in 
pathological examinations may be discarded after using. 
Skins may be scraped more easily on a tanner’s beam, or the rounded 
surface of a smooth log, than on a flat surface. In scraping skins of small 
and thin-skinned mammals a small, round beam may be made of a piece 
of $-inch pipe covered with a piece of rubber hose set into a hole bored in 
the edge of a table. Large beams of the same type may be made of wood 
or metal covered with rubber tubing or a piece of automobile inner tube. 
Rowley (1925, page 123) recommends a scraper made of a sharp-toothed 
hacksaw blade 6 inches long set in a slot sawed in the edge of a flat piece 
of wood or aluminium shaped like an ordinary wooden lath. Hacksaw 
blades of different size in teeth must be used, as long teeth are apt to cut 
through thin skins. Rowley (1925, page 123) states that for fleshing and 
removing fat from small skins in the field, a light currier’s knife handle 
fitted with a hacksaw blade, and used on an upright beam, is worth its 
weight in gold; and that professional trappers of fur-bearing animals could 
save much time by adopting this useful device, instead of cutting off fat 
and flesh with an ordinary skinning knife. For light work a satisfactory 
scraper can be made by flattening the bowl of a large iron mixing spoon, 
cutting the end squarely off, and sharpening and notching the edge with a 
file. Other articles that come in handy at times are found in the ordinary 
house or camp equipment. If the student wishes to go ahead and mount 
specimens, other tools will be found useful. Mounting mammals, however, 
is a skilled art which requires long practice, and cannot be treated in 
this booklet. 
Preservatives 
The preservative recommended as most satisfactory for the skins of 
small mammals and birds is a mixture, in about equal proportions by 
volume, of powdered arsenic (dry white arsenic trioxide, As 2 0 3 ) and 
powdered borax (sodium tetraborate, Na 2 B 4 07 ). These ingredients are 
inexpensive and easily obtained. A pound of arsenic mixed with an equal 
volume of borax will serve an ordinary collector for a long time, and 
should be sufficient to preserve two or three hundred specimens of average 
size. 1 The exact proportions are not very important in practice. As the 
arsenic is the heavier and tends to settle to the bottom, the mixture should 
be frequently shaken up and mixed. This mixture is comparatively safe 
to use, as the borax is harmless and the arsenic dust is heavy and not 
easily inhaled. Arsenic is comparatively insoluble and is not easily 
absorbed by the skin, although if rubbed into an open cut it may make 
a small, festering sore, a purely local irritation. The mixture is poison, 
however, and should be kept conspicuously labelled, as mistaking white 
arsenic for baking powder has been known to cause unpleasant results. 
In the writer’s experience, an overdose of arsenic taken by dogs or cats 
eating a thoroughly poisoned birdskin, merely acted as an emetic, without 
fatal consequences. 
A mixture of powdered arsenic and powdered alum (aluminium sul- 
phate, A 1 2 (S 0 4 ) 3 ), in equal parts by volume or by weight, has for many 
years been a standard preservative for mammal and bird skins, and although 
1 Present regulations limit the purchase of arsenic. It may be obtained by authorized people 
for scientific purposes, but not by amateur taxidermists. 
