knowledge) is the science of the physical properties and chemical characters of crude drugs. Pharmacy is the art of preparing medicinal preparations.

A Dispensatory is a reference book of materia medica. pharmacology, official and unofficial preparations and their doses.

A Pharmacopoeia

to make) is an authoritative hand-book of medicinal preparations.

Expression is the process of forcibly separating a liquid from a solid.

Filtration is the process of separating a solid from a liquid by the intervention of a substance through which the former will not pass.

Solution is the process of changing a substance from a solid or gaseous state to a liquid by the action of a liquid.

Maceration is the process of soaking a drug in a menstruum until the soluble portions are all in solution.

Percolation (percolare, to strain through) is the process by which the soluble portions of a drug are separated from it by the descent of a solvent through it.

Evaporation is the process of driving off from a substance volatile portions by the aid of heat.

Distillation is the process of changing a substance into a gas and condensing it again by cooling.

Chemical Reaction is the combination of substances by changing their molecular structure.

Standardizing is the specification by the pharmacopoeia of the proportion of active ingredient which each drug must possess in order to be official.

Crude Drugs are the parts of plants, shrubs or trees which experience has proved to have medicinal virtues. These vegetable drugs and their preparations are called Galenical.

Alkaloids (al- -the; kali - a plant containing much soda; resemblance), are the active principles of vegetable drugs. They are basic in character, form salts with acids, are insoluble in water, soluble in alcohol, and are precipitated by tannic acid. Their salts are soluble in water and many are insoluble in alcohol. Their pharma-copceial Latin names always end in ina.

Glucosides are vegetable principles which are readily decomposed into glucose and some other substance or substances. Their pliarmacopooial Latin names always end in inum.

Balsams are terms applied to viscid, aromatic exudates from plants consisting of a mixture of resin and a volatile oil. They are insoluble in water and soluble in alcohol.

Gums are thick viscid exudates from plants which harden on exposure to the atmosphere. They are insoluble in alcohol, and soluble in, or at least softened by, water.

Gum Resins are mixed exudates of gums and resins.