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 belly, sore throat, dryness of the mouth, insatiable thirst, difficult breathing and cough; but she recovered. It is well known that quicklime also inflames the skin or even destroys its texture, apparently by withdrawing the water which forms a component part of all soft animal tissues. When thrown into the eyes it causes acute and obstinate ophthalmia, which may end in loss of sight. On this account it will belong, I presume, to the poisons included in the Scottish act against disfiguring or maiming with corrosives.

CHAPTER XI.

OF POISONING WITH AMMONIA AND ITS SALTS.

The second group of the order of alkaline poisons, including ammonia with its salts, and the sulphuret of potass, have a double action on the system, analogous to that possessed by many metallic poisons. They are powerful irritants; but they produce besides, through the medium of the blood, a disorder of some part of the nervous system; and their remote is sometimes more dangerous than their local action. The nervous affection produced by ammonia and the sulphuret of potass closely resembles tetanus, and therefore depends probably on irritation of the spinal column.

Of the Chemical tests for the Ammoniacal Salts.—Ammonia is when pure a gaseous body; but as commonly seen, it exists in solution in water, which dissolves it in large quantity. The solution has the usual effects of alkalis on vegetable colours, with the difference, however,—that the changes of colour are not permanent under the action of heat. It forms a yellow precipitate, as potass does, with chloride of platinum. It may at once be distinguished from other fluids by its peculiar pungent odour, which is possessed by no other substance except its carbonate.

Various carbonates are known in chemistry, but the only one known in commerce or met with in the shops is the sesqui-carbonate (sub-*carbonate—smelling salt—volatile salt—hartshorn). It is solid, white, fibrous, and has the same odour as pure ammonia. Its solution differs little in physical properties from the pure liquid ammonia; but, unlike it, is precipitated by the salts of lime.

The hydrochlorate (muriate of ammonia—sal ammoniac)—is known by its solid, white, crystalline appearance; its ductility; its volatility; and by the effect of caustic potass and nitrate of silver, the former of which disengages an ammoniacal odour, while the latter causes in a solution of the salt a white precipitate, the chloride of silver.

Of the action of the Ammoniacal Salts, and their effects on man.—To determine the action of ammonia on the animal system, Professor Orfila injected sixty grains of the pure solution into the jugular vein