h._--Neutralize the contents of the
stomach, if acid, with sodium carbonate; place them in a retort and
carefully distil. Collect the distillate, mix with chloride of calcium
or anhydrous sulphate of copper, and again distil. Agitate distillate
with dry potassium carbonate, and draw off some of the supernatant fluid
for testing.

_Tests._--Odour. Dissolves camphor. With dilute sulphuric acid and
bichromate of potassium turns green, and evolves aldehyde. Product of
combustion makes lime-water white and turbid.

=Methyl Alcohol: Wood Naphtha.=--Used to produce intoxication by
painters, furniture-polishers, etc.

_Symptoms_ are those of alcoholic poisoning, but vomiting and delirium
are more persistent. Total or partial blindness may follow as a sequel
of optic atrophy. A fatal result not infrequently follows.

The following table gives the points of distinction between concussion
of brain, alcoholic poisoning, and opium poisoning:

CONCUSSION OF BRAIN. ALCOHOL. OPIUM.

1. Marks of violence 1. No marks of violence, 1. As alcohol.
on head. unless person has
fallen. History will
be of use.

2. Stupor, sudden. 2. Excitement precedes 2. Symptoms slow.
sudden stupor. Drowsiness, stupor,
lethargy.

3. Face pale, cold; 3. Face flushed; pupils 3. Face pale; pupils
pupils sluggish, generally dilated. contracted.
sometimes dilated.

4. Remission rare. 4. Partial recovery may 4. Remission rare.
Patient recovers occur, followed by
slowly. death.

5. No odour of alcohol 5. Odour of alcohol 5. Odour of opium in
in breath. in breath. breath.

=Ether= is a volatile liquid prepared from ethylic alcohol by
interaction with sulphuric acid. It contains 92 per cent. of ethyl oxide
(C_{2}H_{5})O. It was formerly called 'sulphuric ether.' It is a
colourless, inflammable liquid, having a strong and characteristic
odour, specific gravity 0.735. =Purified ether= from which the ethylic
alcohol has been removed by washing with distilled water, and most of
the water by subsequent distillation in the presence of calcium chloride
and lime. It is this preparation which is used for the production of
general anaesthesia. It has a specific gravity