It is, I believe, more efficacious if laid on hot than cold, but the danger to health is greater. I venture to say that if there is anything which will preserve objects for an indefinite period it is corrosive sublimate. Deadly though it be, and dangerous to work with, it has the advantage of being used as a finishing preparation, and therefore need not, except in extreme cases, be handled.
Instead of rectified spirits of wine, I have used with much success as an exterior wash for valuable bird skins, the following:
No. 18. — Preservative Wash.
Pure sulphuric ether, 1 pint.
Corrosive sublimate, 6 grs.
Keep in a stoppered bottle, labelled "Poison," and when used apply with a brush. This is more rapid in its evaporation than spirits of wine, but is very expensive. Of course, the more rapidly any spirit evaporates, and deposits poison previously held in solution, the better chance you have of not spoiling your specimens.
PRESERVATIVE FLUIDS FOR FISHES AND REPTILES.
I have lately given a great deal of attention to the preservation of fishes — and especially large ones — in some fluid which should have four advantages:
1. Perfect preservation of the specimen — and which also, if a foreign one, is consequently a long time in transit.
2. Its freedom from causing great shrinking or shrivelling of the integument.