Conspectus of the pharmacopoeias of the London, Edinburgh, and Dublin Colleges of Physicians ... / [Anthony Todd Thomson].

  • Thomson, Anthony Todd, 1778-1849.
Date:
1830
Catalogue details

Licence: Public Domain Mark

Credit: Conspectus of the pharmacopoeias of the London, Edinburgh, and Dublin Colleges of Physicians ... / [Anthony Todd Thomson]. Source: Wellcome Collection.

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    exposing ii in a crucible to a red heat, so as to expel the sulphate of ammonia:—the sulphate of potass, wlien present, will remain in the crucible. A'i7Wc acid is often adulterated with sulpfiuric and muriatic acids. These adulterations are discovered by dropping into the sulphuric acid a solution of nitrate of barytes, which is precipitated white, if sulphuric acid be present; and a solution of nitrate of silver, the precipitation of a muriate of which shows the presence of muriatic acid. In tlie same manner aetdis detected in acetic acid, by dropping into it a solution of acetate of barytes; copper, by the a-id becoming bluish when supersaturated with ammonia; and lead, by a black ])recipitate being thrown down when sulphuretted hydrogen gas is added to it. ALKALIES, AND THEIR SALTS. Two of the ALKALIES employed in Pharmacy are compounds of oji/ffcn with metallic basesthe other is a compound of hydrofren and azote. They possess properties the reverse of the acids. Their taste is urinous and acrid; they change to green the vegetable blue and red colours; arc caustic, or inflame and corrode the skin, and dissolve animal matter; have a strong aflinity for water, and by their greater solubility in it are distinguished from the earths; unite with oils aud fat forming soap; and form neutral salts with the acids. There are three mineral alkalies: one is volatile, and cannot be ob- tained perfectly pure in a solid form; the other two are fixed. They should be kept in well-stopped glass-bottles, and dispensed in glass- stoiipcd phials. Ammonia, the volatile alkali, is often over-diluted with water, which may be known by the spec. grav. of the fluid: or, a phial capable of containing 224 grams of distilled water, should hold 21U grains of litiuor ammonia:. Liquor potassa: often contains lime, which is known by the solution, diluted with distilled water, becom- ing milky when the breath is blown through it, the lime being thus formed into a carbonate. The purity of potash, in the solid form, is of little consequence, as it is used for external application only ; pure soda is not used in medicine. Alkaline Salts should, when neutral, have neither alkaline nor aciil properties; but occasionally the one or the other evidently preilominates. When it is the acid which is in excess, super is added to the appellation of the salt, as supercarbonate of potash ; when the alkali, sub, as subcarbonate of potash. They require for their solution various proportions of water, from one-half to 2,(K)0 times the weight of the salt. When they attract moisture they are said to he deliquescent: when they lose their water of crysUllization, become opaque, dry, and easily fall to ]iowdci, rjjloresccnt; if, when exposed to heat, they gradually dry to a mass, they are said to undergo tlic