A conspectus of the pharmacopoeias of the London, Edinburgh, and Dublin, Colleges of Physicians : being a practical compendium of materia medica and pharmacy / By Anthony Todd Thomson.

  • Anthony Todd Thomson
Date:
1825
Catalogue details

Licence: Public Domain Mark

Credit: A conspectus of the pharmacopoeias of the London, Edinburgh, and Dublin, Colleges of Physicians : being a practical compendium of materia medica and pharmacy / By Anthony Todd Thomson. Source: Wellcome Collection.

    13/238
    arid properties; hut ocrasionally the one or liie oiUer evidenlK pn;: dominates. When it is the acid which is in excess, super is uddcii to the appellation of the solt, as supercarbonate of potash ; wlicn thelilkaU, sub, as subcarbonate of potash. They require for their solution various proportions of water, from one half to 2000 times the weight of the salt. When they attract moisture, they are said to be deliquescent; when they lose their water of crystallization, be- come opaque, dry, and easily fall to powder, efflorescent; if, wlien exposed to h*caVthey gradually dry to a mass, they arc said to under- go the watery fusion ; and to decrepitate., if they split, fly, and crackle, when exposed to a high tcmjieraturc. The salts most commonly adulterated are suhearbonas potassts and subcarbunas soda. To try the first, make a solution of one part of the salt in eight of distilled water. If this become turbid after being neutralized with pure nitric acid, it indicates the presence of silex ; if a white precipitate bo tlirown down by muriate of barytes, or acetate of lead, sulphuric salts are indicated ; and 7nuri- atic salts by a white precipitate being formed with nitrate of silvcr- If a white precipitate be produced by a solution of oxalate of pot- ash, lime, or its carbonates, is present. The same tests show iJie presence of similar substances in subcarbonate of soda, if added to a saturated solution of it in acetous acid. The addition of tartaric acid discovers potash, by forming a precipitate of supertartrate of potasli. The deliquescent and efflorescent salts should be kept and dispensed in stopped bottles; while those that are persistent will not sufier from being put up in paper. EARTHS, AXD THEIR SALTS. The earths, like the alkalies, arc probably compounds of oxygen with metallic bases. They are of very difficult fusibility; very sparingly soluble ; and unite with the acid.s, forming neutral salts. Those that are soluble in water possess properties very similar to those of tlic alkalies; they are caustic; change to green vegetable blues and reds; and, combiitcd with oils, form soap. Two cartlis, only, in their pure slate, are used in medicine ; lime and magnesia. The former, which is chiefly employed in pharma- ceutical operations, should be used as soon after it is burnt as possi- ble ; and each should be preserved in very closely-stopped bottles, as both attract, powerfully, the carbonic acid contained in atmospheric air. The solution of lime, or lime water, should b.O kept in Kmnjl
    digitised image 1
    digitised image 2
    digitised image 3