does the same with woollen clothes, from the formation of _picric_ acid.

_Fatal Dose._--Two drachms.

_Fatal Period._--Shortest, one hour and three-quarters in an adult; in
infants in a few minutes, from suffocation.

XII.--HYDROCHLORIC ACID

=Hydrochloric Acid=, muriatic acid, or spirit of salt, is not uncommonly
used for suicidal purposes, being fifth in the list.

_Method of Extraction from the Stomach._--The same as for sulphuric
acid. As hydrochloric acid is a constituent of the gastric juice, the
signs of the acid must be looked for.

_Post-Mortem Appearances._--The mucous membranes are dry, white, and
shrivelled, and often eroded.

_Tests._--The concentrated acid yields dense white fumes with ammonia.
When warmed with black oxide of manganese and strong sulphuric acid it
gives off chlorine, recognized by its smell and bleaching properties.
Diluted it gives with nitrate of silver, a white precipitate, which is
insoluble in nitric acid and in caustic potash, but is soluble in
ammonia, and when dried and heated melts, and forms a horny mass. Stains
on clothing are reddish-brown in colour.

_Fatal Dose._--Half an ounce.

_Fatal Period._--Shortest, two hours; average, twenty-four hours. Death
may occur after an interval of some weeks from destruction of the
gastric glands and inability to digest food.

XIII.--OXALIC ACID

=Oxalic Acid= is used by suicides, though not often by murderers. The
crystals closely resemble those of Epsom salts or sulphate of zinc;
oxalic acid has been taken in mistake for the former. It is in common
use for cleansing brass, in laundry work, for dyeing purposes, and
especially for bleaching straw hats.

_Symptoms._--If a concentrated solution be taken, it acts as a
corrosive, causing a burning acid, intensely sour taste, which comes on
immediately, great pain and tenderness and burning at pit of stomach,
pain and tightness in throat. Vomiting of mucus, bloody or dark
coffee-ground matters, purging and tenesmus, followed by collapse,
feeble pulse, cyanosis and pallor of the skin; also swelling of tongue,
with dysphagia. In some cases cramps and numbness in limbs, pain in head
and back, delirium and convulsions. May be tetanus or coma. If taken
freely diluted, the nervous symptoms predominate, and may resemble
narcotic poisoning. Sometimes almost instant death.

_Post-Mortem Appearances._--Mucous membrane of mouth, throat, and
gullet, white and softened, as if t