This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
This is a concrete juice obtained by incisions in the unripe capsules of Papaver somniferum, or the poppy, an annual plant, inhabiting Asia, in different parts of which, as well as in Egypt, it is abundantly cultivated for the sake of the opium which it yields. There are two varieties of the plant, the white and black, both of which afford opium; but it is said to be chiefly procured from the former. (See Poppy Capsules.) The juice, when collected, is put into convenient receptacles, and, after concreting into a proper consistence, is made up, either with or without addition, into masses of different shape, usually surrounded with leaves to prevent their adhering together, and then sent into market.
Commerce is supplied with opium chiefly from Hindustan, Anatolia or Asia Minor, and Egypt. It is produced also in Persia; but little or none is exported. The opium of Hindostan is either consumed in India, or sent to China, and reaches Europe and this country only as an object of curiosity. It is the product of the Asiatic dominions of Turkey, and that of Egypt, with which the western world is supplied. The opium consumed in the United States is chiefly the variety produced in Anatolia, and introduced into commerce through the ports of Smyrna and Constantinople. It is called Turkey opium, and is usually distinguished into two varieties, the Smyrna and Constantinople opium so named from the ports from which they are respectively distributed. Of these, the Smyrna opium is the one most largely consumed in this country. Some Egyptian opium is occasionally imported; but is seldom kept in the shops.