The standard works upon medical chemistry enter so fully into all essential data with regard to inorganic drugs that it is unnecessary to discuss the matter here. With regard to serum medication, special works should be consulted.

Botanic drugs present so many special problems with regard to their pharmaceutic manipulation that some discussion of the matter is imperative in elucidating the therapy of the small dose. The climatic conditions, the soil, the conditions of growth, the changes taking place during growth, the time and manner of harvesting, curing and shipping, as well as the length of time the cured product is kept in stock, all markedly influence vegetable drugs. Great variations occur in different lots derived from the same source of supply, and careful manufacturing pharmacists seldom purchase before a working trial is made of a lot as to the character of its extract, the ease of alkaloidal separation, and the assayed values.