This section is from the book "The London Medical Dictionary", by Bartholomew Parr. Also available from Amazon: London Medical Dictionary.
(From the Arabic term carkim). Turmeric. Crocus Indicus, terra marita, cyperi genus ex India, cannacorus radice croceo,manjella,kua, kaha; by the Indians, borri-borri; by the Portuguese, saffran de terra; the Arabians call every root of a saffron colour by this name, curcuma. There are two species, the long and the round rooted; but the first is the best, and chiefly used. It is the curcuma longa Lin. Sp. Pi. 103. Indian long rooted turmeric.
The root is the only part in use; brought from the East Indies; small, tuberous, and knotty; externally greyish coloured, but internally of a deep lively yellow lending to red. It hath a slight aromatic and bitterish taste, and somewhat disagreeable smell. It gives out its virtues both to water and to spirit; by distillation with water, a small quantity of essential oil is obtained; and from the remaining decoction a bitter extract is procured by evaporation. The spirituous extract retains nearly the whole virtue of the root.
It has been thought a powerful remedy in obstructions of the viscera, particularly the abdominal; in icteric and uterine disorders. The dose may be from a scruple to a drachm, but it is now very rarely used. The powder is often mixed with yellow peas, ground fine; the roots should be chosen of the largest size, fresh, compact, heavy, not easy to break, of a lightish yellow without, and a deep reddish yellow within.
It is chiefly consumed by the dyers. See Lewis's Mat. Med. Neumann's Chemical works.