446 MEDICINES. 



Mild as is its operation in most animals, it sometimes gripes, and 

 even endangers the horse. 



Catechu, Japan Earth, — yet, no earth, but extracted from 

 the wood of one of the acacia trees, is a very useful astringent. 

 It is given in over purging, in doses of one or two drachms, 

 with opium, as a yet more powerful astringent ; chalk, to neu- 

 tralize any acid in the stomach or bowels ; and powdered gum, 

 to sheath the over-irritated mucous coat of the intestines. It is 

 not often adulterated in our country, but grossly so abroad — fine 

 sand and alumnious earth being mixed with the extract. It is 

 seldom given with any alkali, yet the prescription just recom- 

 mended contains chalk : but, although the chalk, as an alkan. 

 may weaken the astringency of the catechu, it probably neu- 

 tralizes some acid in the stomach or bowels, that would have 

 diminished the power of the catechu to a greater degree. It 

 must not be given in conjunction with any metallic salt, for the 

 tannin or gallic acid, on Avhich its power chiefly or entirely 

 depends, has an affinity for all metals, and will unite with them, 

 and form a gallate of them, possessing little astringent energy 

 Common ink is the union of this tannin principle with iron. 



A tincture of catechu is sometimes made by macerating three 

 ounces of the powder in a quart of spirit for a fortnight. It is 

 an excellent application for wounds ; and, with the aloes, con- 

 stitutes all that we want of a balsamic nature for the purpose 

 of hastening the healing process of wounds. 



Caustics, — are substances that burn or destroy the parts to 

 which they are applied. First among them stands the red-hot 

 iron, or actual cautery, and then pure alkalies, potash, and soda, 

 and the sulphuric and nitrous acids. Milder caustics are found 

 in the sulphate of copper, red precipitate, burnt alum, and ver- 

 digris. They are principally used to destroy fungous excrescences, 

 or stimulate indolent tumors, or remove portions of cellular sub- 

 stance, or muscle infected by any poison. 



Chalk, — see Creta Preparata. 



Chamomile, Anthemis. — The powder of the flower is a use- 

 ful vegetable ionic, and the mildest in our list. , It is given in 

 doses of one or two drachms, and is exhibited in the early stage 

 of convalescence in order to ascertain whether the febrile stage 

 of the disease is passed, and to prepare the way for a more pow- 

 erful tonic, the gentian. If no acceleration of pulse, or heat of 

 mouth, or indication of return of fever, accompanies the cautious 

 use of chamomile, the gentian, with carbonate of iron, may be 

 safely ventured upon ; but if the gentian had been first used, 

 and a little too soon, there might have been considerable, and 

 perhaps dangerous return of fever. 



Charcoal,— is occasionally used as an antiseptic, being made 



