llest)._--Half a drachm of the B.P. acid, equal to 0.6
grain of the anhydrous. _Recovery_ from 1/2 ounce of the B.P. acid.
These records are fallacious, for in specimens the percentage of
anhydrous acid varies enormously. Practically, 1 grain of the anhydrous
acid is fatal.

_Fatal Period._--From two to five minutes after a large dose, but may be
less.

_Method of Extraction from the Stomach._--Having previously carefully
fitted a watchglass to a wide-mouthed bottle, nearly fill the bottle
with the contents of the stomach, blood, secretions, etc. Place a few
drops of a solution of nitrate of silver on the concave surface of the
watchglass, and cover the mouth of the bottle with it. The vapour of
hydrocyanic acid, if present, will form a white precipitate which may be
tested. Other watchglasses, treated with sulphide of ammonium or
sulphate of iron and liquor potassae, will give the reactions of the acid
with appropriate tests. This method removes all objections as to foreign
admixture. If the acid is not at first detected, gentle warming of the
bottle in a water-bath will assist the evolution of the vapour. The
vapour may be obtained by distillation, but this process is open to
objections to which the other is not. In some cases it becomes changed
in the body into formic acid, which should therefore be sought for.

_Tests._--With nitrate of silver a white precipitate, insoluble in cold,
but soluble in boiling, nitric acid. The precipitate heated, evolves
cyanogen, having an odour of peach-blossoms, and burning, when lighted,
with a pink flame. Liquor potassae and sulphate of iron give a
brownish-green precipitate, which turns to Prussian blue with
hydrochloric acid. Liquor potassae and sulphate of copper give a
greenish-white precipitate, becoming white with hydrochloric acid.
Sulphide of ammonium gives sulpho-cyanide of ammonium. This develops a
blood-red colour with perchloride of iron, bleached by corrosive
sublimate.

XLII.--ACONITE

=Aconite= (_Aconitum Napellus_, monkshood).--Root and leaves. Poisonous
property depends upon an alkaloid, aconitine. Aconite is one of the
constituents of St. Jacob's Oil.

_Symptoms._--Numbness and tingling in mouth, throat, and stomach,
giddiness, loss of sensation, deafness, dimness of sight, paralysis,
first of the lower and then of the upper extremities, vomiting, and
shallow respiration. Pupils dilated. Pulse small, irregular, finally
imperceptible. The mind remai