1174
ELEMENTS OF MATERIA MEDICA.
olive oil. It has a pale yellowish colour, a peculiar, not disagreeodour, and a bitter somewhat acrid and nauseous taste. Its sp-less than that of water, but is not constant. It is 0 - 95 accordingSchbnberg, while Stoltze says it is 0 966. By keeping it becomes c °siderably denser. Balsam of copaiva is insoluble in water, but is c °pletely soluble in alcohol, ether, and the oils, both fixed and volaWhen acted on by alkalies it yields a kind of soap, which is insolublewater.
11 gg
Considerable variation exists in the colour, consistence, and sp. gr. of, as wen , ethe relative quantities of volatile oil and resin yielded by, balsam of copaiva. kv 6 ; ,
odour and taste vary somewhat. The differences doubtless depend in great partthe balsam being procured from different species. The smaller species, which *in the interior of the Brazils, as in Bahia and Minas, yield, as we are told, less ha - ^but it is more resinous and sharper. Brazilian Copaiva is thin, clear, and pale- co *“j| o , V)West Indian Copaiva (produced probably by C. officinalis ) is thick, golden-}y. tur .not transparent, and has a less agreeable smell, which is somew hat like that open tine.
Adulteration. —There is no reason to suppose that balsam ofcop a ^,is adulterated in this country now; though the fact mentioned by ^Paris ( Pharmacologia , ii. 183, 6th ed.) proves that formerly it '' () f“ A curious trial took place some time since, between the °" nel ^ lirlcertain premises that were burnt down, and the Governors of theFire-Office, in consequence of the latter refusing to indemnify the 1prietor for his loss, because the fire had been occasioned by his j^.Balsam of Copaiba.”—Gray ( Suppl. to the Pkarm.) has published ^for making a balsamum copaibce reductum, as well as copaiba factiThe Edinburgh College gives the following characters of its purity 1 ' -
f alcfl^ *
“ Transparent: free of turpentine odour when heated : soluble in two parts <n jeit dissolves a fourth of its weight of carbonate of magnesia, with the aid of 3 s
heat, and continues translucent.”
The turpentine odour may be recognized by dropping the susp ebalsam on a heated iron (as a spatula).—The mixture of magnesi^^copaiva here referred to, acquires, in several hours, the translu ^ gt
This i-If one
of
aspect, and consistency of very thick mucilage of gum arabicis due to Blondeau ( Journ. de Chim. Med. i. 560 : and ii. -fully
two drops of suspected balsam be placed on unsized paper, and car s j uC idheated over a lamp to expel the volatile oil, an homogeneous f ran caS totspot is left, if the balsam be pure, but if it have been mixed withoil, the spot of resin is surrounded by an oily areola (Chevalher, ^de Chim. Med. t. iv. p. 619). Blanche {Journ. de Pharm. xi. J yithrecommended ammonia as a test. If pure balsam be shaken ^liquor ammoniae (sp. gr. 0‘965) it becomes clear and transparentinstants ; not so when castor oil is present. Ebullition with " a 0 {expel the volatile oil and obtain the hard resin);—and the aCpotash, and of sulphuric acid, have also been proposed as tests.
Composition. —F. Hoffmann (Obs. Pliys. Chym. lib. i. obs. vl - •'^fion-t. iv. p.454. Gen. 1748) submitted copaiva to a chemical exam*Afterwards Schbnberg (Pfaff, Mat. Med. iv. 12) analysed it. a (leStoltze (Berl. Jahrb. xxvii. 2, 179), and, in 1829, GerberPharm. xvi. 79 and 367) submitted it to analysis.