POISONS.

347

precipitate being soluble in nitric, but not in an excess of oxali -,acid. Exposed to heat it volatilizes, leaving but a little residue.It is decomposed by sulphuric acid, becoming brown ; it is dissolv-ed by heat and nitric acid, and rendered yellow. Muriatic aciddissolves and decomposes it with heat. Oxalic acid also turns itto a light-brown red.

Phosphoric acid precipitates barytes and lime-water ; the pre-cipitate being soluble in nitric acid. It is decomposed by char-coal at a high temperature, evolving carbonic acid, and phosphorugbeing sublimed.

Fluoric acid exhales white vapours, not dissimilar to those ofmuriatic acid ; heat is evolved with a hissing noise when water isadded to it : it dissolves glass.

Tartaric acid produces a precipitate from lime-water, soluble inan excess of acid, and in nitric also ; with potash it forms a neu-tral and supersalt. It does not precipitate solution of silver, butits salts do.

Prussic acid has a strong odour of bitter almonds, and is con-tained in that fruit, and in the leaves of the peach and the laurel ;it is soluble in alcohol, but hardly in water, and is precipitated inits solution by nitrate of silver.

ALKALIES. (Potash, Soda, Ammonia.)

Syinptoms. — The symptoms of having swallowed an alkali in ex-cess are, an acid, urinous and acrid taste in the mouth ; greatheat in the throat, nausea and vomiting of bloody matter, whichchanges syrup of violets to green, and effervesces with acids, if thecarbonated form of the acid has been taken ; copious stools ; acutepain of the stomach, colic, convulsions, death.

Treatment. — Give vinegar and other vegetable acids largely, toneutralize the alkali ; and treat the concomitant symptoms upongeneral principles.

Tests. — Alkalies have many properties in common ; their solu-tions feel soapy ; they change vegetable blues to green, and yel-low to brown ; remain transparent when carbonic acid is added tothem, which serves to distinguish them from the alkaline earths,barytes, strontium, and lime. Nitrate of silver is precipitated bythem in form of a dark coloured oxide, soluble in nitric acid.

%* Potash and soda may be distinguished from each other byevaporating their solutions to dryness ; potash will become moistby absorbing water from the atmosphere, while soda will remaindry. Ammonia is known by its pungent smell.

ALKALINE EARTHS. (Lime, Barytes, Pure Barytes, Car-

bonate and Muriate of.)

Symptoms. Violent vomitings, convulsions, palsy of the limbs,distressing pains in the abdomen, hiccup, alteration of the counte-nance, and very early death.

Treatment. — If lime has been taken, vinegar and other vegetableacids are the best antidotes.

If barytes, in any of its forms, has been swallowed, a weak so*lution of Epsom or Glauber's salt should be copiously drank; t«