74 PRESERVING INSECTS. 
I apply it to black substances, and perceive that it 
leaves little white particles on them, I then make it 
weaker by adding alcohol. A black feather, dipped 
into the solution, and then dried, will be a very good 
test of the state of the solution. If it be too strong, 
it will leave a whiteness upon the feather. 
A preparation of arsenic is frequently used; but 
it is very dangerous, and sometimes attended with 
lamentable consequences. I knew a naturalist, by 
name Howe, in Cayenne, in French Guiana, who 
had lost sixteen of his teeth. He kept them in a 
box, and showed them to me. On opening the lid 
— “These fine teeth,” said he, “ once belonged to 
my jaws: they all dropped out by my making use 
of the savon arsenetique for preserving the skins of 
animals.” I take this opportunity of remarking that 
it is my firm conviction, that the arsenetical soap can 
never be used with any success, if you wish to re- 
store the true form and figure to a skin. 
I fear that your correspondent may make use of 
tight boxes and aromatic atmospheres, and still, in 
the end, not be completely successful in preserving 
his specimens from the depredation of insects. The 
tight box and aromatic atmosphere will certainly do 
a great deal for him; but they are liable to fail, for 
this obvious reason, viz. that they do not render, for 
ever, absolutely baneful and abhorrent to the depre- 
dator, that which in itself is nutritious and grateful 
tohim. In an evil hour, through neglect in keeping 
up a poisoned atmosphere, the specimens collected 
by your correspondent’s industry, and prepared by 
his art, and which ought to live, as it were, for the 
