This section is from the book "A Text-Book Of Pharmacology, Therapeutics And Materia Medica", by T. Lauder Brunton. Also available from Amazon: A text-book of pharmacology, therapeutics and materia medica.
A gum resin obtained from Garcinia Hanburii (Garcinia Morella, var. pedicellata). Imported from Siam.
Characters. - In cylindrical pieces, sometimes hollow in the centre, 1 or 2 inches in diameter, breaking easily with a smooth conchoidal glistening fracture; colour tawny, changing to yellow when it is rubbed with water; taste acrid; powder, bright yellow.
Adulteration. - Starch fraudulently added.
Test. - An emulsion made with boiling water, and cooled, does not become green with the solution of iodine.
Dose. - 1-4 grs.
Pilula Cambogiae Composita (vide p. 522).......................................
Pilulae Catharticae Compositae (vide p. 523).......................................
Action and Use. - It is a drastic hydragogue purgative, and large doses causes violent irritation of the alimentary canal, with vomiting and griping. It is used in combination with other purgatives as a derivative in cerebral affections, also with cream tartar in dropsies. It has been used as an anthelmintic. Ternstromiaceae. Thea. Tea. Not officinal. - The dried leaves of Thea sinensis. China, Assam, Ceylon, etc. Characters. - Both green and black tea are prepared from the same species of thea. Green teas are obtained by drying the freshly-gathered leaves on a hot iron plate until they shrivel. Black teas are obtained by allowing the leaves to lie in heaps and undergo a kind of fermentation before drying them.
Composition. - They contain theine, a volatile oil, and tannin.
Action. - The action probably depends partly on the theine and partly on the volatile oil they contain. Both green and black teas are powerful cerebral stimulants. They render the mental faculties more active and tend to prevent sleep. Green tea is much more powerful than black, and its admixture with black is sometimes the cause of sleeplessness in persons who have thus taken it unconsciously. In some persons it produces giddiness, restlessness, and such severe muscular trembling that the hand shakes violently. A quantity of tea eaten by a horse caused great excitement, and probably anaesthesia, as the animal killed itself by dashing its head against a stone. Both green and black teas are apt to cause indigestion. This is probably due, in some measure at least, to the tannin they contain. Tea mixed with gastric juice lessens its power of digesting fresh meat, but not of digesting smoked meat. This is probably due to the tannin hardening the soft fibre of fresh meat, but leaving the comparatively hard fibre of dried meat, ham, etc. unchanged. To avoid getting much tannin it is advisable not to let the tea stand long on the leaves, but pour it off quickly, so that the volatile oil which gives the aroma only is extracted.
Use. - As a cerebral stimulant to relieve drowsiness and headache.