The materia medica furnished by the Arab physician Rhazes in the different works which he has written, is unusually rich in simple elements, the majority of which are always drugs of a rather mild action; Greece, Persia, Syria, East India and Egypt were the sources from which they were derived. Beside the simple elements, Rhazes mentions a number of composite preparations of drugs. As not a few of the latter required very careful manipulation, it may safely be inferred that the Arabian apothecaries of the ninth century had already acquired considerable skill and experience in their special field of work. At Salerno, during the first half of the twelfth century, pharmacy began to assume a position of considerable importance. The work which was prepared by Nicolaus Praepositus, and which was known as an “Antidotarium,” furnished quite full information with regard to the characters and therapeutic uses of nearly 150 different drugs. According to Berendes this work served for several centuries as the basis of later pharmacopoeias. One of its notable features is the importance which the author attaches to the duty of weighing very carefully each of the drugs that enter into the composition of a given preparation, of gathering certain vegetable products at the right season, and of paying strict attention to their quality and to the manner of preserving them. In 1140 A. D., Roger, King of Naples and Sicily, promulgated a law which defined what should be the proper relations between physicians and apothecaries; and about one hundred years later (1241 A. D.) Frederick II. amplified and gave greater precision to this law, thus establishing what was practically an Institute of Apothecaries. The following provisions constitute the essential features of the law:-- 1. The physician and the apothecary shall have no business interests in common. 2. The physician shall not himself conduct an apothecary shop. 3. In each department of the kingdom two respectable men, selected by the Faculty at Salerno, shall be assigned the duty of furnishing sworn statements to the effect that all the electuaries, syrups, and other preparations of drugs kept for sale in a given apothecary shop, have been made according to the established prescriptions and are offered for sale only in that state. 4. In the case of those preparations which ordinarily do not keep for a longer time than one year without spoiling, the price at which they are to be sold shall be at the rate of 3 Tarreni (about 30 cents) per ounce; while those which ordinarily remain unchanged during a longer period, shall be valued at 6 Tarreni per ounce.