Specimens of natural history intended for subsequent examination and dissection are best preserved in alcohol, but as this is expensive, a saturated solution of 100 parts of alum and 2 parts of saltpetre may be used with good effect. For preserving stuffed specimens the following are generally used:

Arsenical Soap

This is the most powerful preservative in use. It is a strong poison, but is invaluable for preserving skins of birds and beasts that are to be stuffed. It is made thus: Powdered arsenic, 2 oz.; canqohor, 5 oz.; white soap, 2 oz.; salt of tartar (sub-carbonate of potash), 6 drachms; powdered lime, 2 drachms. Cut the soap in very thin slices and heat gently with a small quantity of water, stining all the time with a stick. When thoroughly melted add the salt of tartar and the lime. When these are well mixed together add the arsenic, which must be carefully incorporated with the other ingredients. Take the mixture off the fire, and while cooling add the camphor, previously reduced to powder by rubbing it with a little alcohol. When finished the soap should be of the consistence of thick cream and should be kept in a tightly stopped bottle.

Arsenical Preservative Powder

This is dusted over moist skins and flesh, and preserves almost any animal matter from putrefaction. It is thus made: Arsenic, 4 oz.; burnt alum, 4 oz.; tanner's bark, 8 oz; mix and grind together to a very fine powder.