1. Pharmaceutic - alcohol, glycerin, sugar, benzoin, aromatic oils, boric acid.

2. Foods - boric acid, borax, saltpeter (Kn03), salicylic acid, sodium benzoate, formaldehyd, sodium chloride (butter, ham, fish, corned beef), smoke (smoked beef and ham), sugar, vinegar.

3. Anatomic material - formaldehyd, acetic acid, arsenic, alcohol, glycerin, potassium bichromate.

4. Antitoxins, vaccines - glycerin, trichlorphenol, phenol, tri-kresol.

Alcohol is the most useful preservative for vegetable drugs in solution; thus tinctures and fluidextracts keep well, while aqueous solutions, such as infusions, do not. A saturated solution of sugar is antiseptic, as seen in jams and medicinal syrups; syrups less than saturated will ferment or mold. Glycerin is a much-used preservative of vegetable extracts. To preserve meat, borax and saltpeter are used, or the meat is salted or smoked (as ham, corned beef, smoked beef, etc.); through exposure to smoke it absorbs cre-osols and other wood-tar constituents. Boric acid, sodium benzoate, salicylic acid, and formaldehyd are added to various canned and preserved foods and to milk, cream, and butter. Boric acid will also retard the common fungus growth in solutions of chemicals, such as cocaine. A too much used preservative of milk is formaldehyd, which, in amounts sufficient to keep milk for a week, cannot be detected by its odor. Lard may be kept from becoming rancid for a time by the presence of benzoin, as in benzoinated lard. Butter is believed to keep better when it is salted. Chemically preserved foods (embalmed foods) are usually less readily digested than normally, as their tissues are hardened, and also the preservatives interfere with the activity of the digestive ferments.