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488                                                MEDICAL JURISPRUDENCE

vapour of phosphorus gains access to the jaw (phossy jaw) through a carious
tooth or an interspace caused by a missing tooth. Death occurs from
debility, blood poisoning or pyogenic infection. Abortion usually occurs
among pregnant women.

Treatment.—Advise thorough cleanliness and ventilation by the use of
extraction fans in the match factories. The air of the work rooms may be
saturated with turpentine. The teeth of the workmen should be occasionally
examined, and tKeteeth, if found carious, should be filled in or extracted.
The workmen should also be persuaded to use systematically mouth washes
of sodium bicarbonate.

Chemical Analysis.—Phosphorus may be separated by distillation from
organic mixtures, and may be detected by its smell and luminosity in the
dark. Its phosphorescence is diminished by the presence of alcohol. Hence,
in cases of suspected phosphorus poisoning a saturated solution of common
salt should be used as a preservative instead of alcohol. It can also be
separated by shaking the contents of the stomach, etc. with carbon bisul-
phide, which dissolves phosphorus.

Tests.—1, Scherer's Test.—The suspected material in a finally divided
condition is placed in a conical flask with a capacity of about 500 cc. and
covered with cold water. A few cubic centimetres of cadmium sulphate
solution are added and the liquid is acidified with dilute sulphuric acid.
The flask is closed with a cork having two slits from which are suspended
two strips of filter paper, one soaked in 5 per cent silver nitrate solution and
the other in a solution made by adding sodium hydroxide solution to 5 per
cent lead acetate solution until the precipitate first formed is redissolved.
The strips of filter paper must be so arranged as not to touch each other or
the sides of the flask. The flask is then heated on a water bath in the dark
to'40° or 50 °C. If the silver paper darkens from the fumes, while the lead
paper does not change, phosphorus may be present. If the silver paper does
not darken, phosphorus is not present. If both the papers darken, hydrogen
sulphide is present, or both hydrogen sulphide and phosphorus may be

2.    Mitscherlicli's Test.—If the mixture is acidulated with sulphuric acid
and distilled, the luminous vapour of phosphorus will be seen in the cool
condenser in the dark.   Certain substances, such as alcohol, ether, chloro-
form, phenol and turpentine, if present, will prevent the development of
luminosity.   This is a very delicate test, and will reveal one part of phos-
phorus in 100,000 parts of the material.

3.    Phosphine   Test.—If   hydrogen   is   passed   through   the   warmed
suspected fluid material, phosphoretted hydrogen is evolved, which will burn
with a green flame.   If the gas is passed into a solution of silver nitrate, a
black  precipitate  is  formed.   The   green  flame,   when   examined  with  a
spectroscope, shows one band in the orange and yellow between C and D,
but very close to D, and several bands in the green.   This test is also known
as Dusart-Blondlot's test.

4.    Heated with a few drops of strong nitric acid and some ammonium
molybdate solution a concentrated acid solution of the suspected material
gives a yellow, crystalline precipitate, if phosphorus is present.

Medico-Legal Points.—The poisonous effects are more powerful if phos-
phorus is dissolved or well triturated than when used in solid lumps.

In Europe, phosphorus poisoning is usually suicidal. Pregnant women
have often been accidentally poisoned by phosphorus as they take it to induce
criminal abortion. It is seldom used for homicidal purposes. The odour
and taste as also the luminosity in the dark reveal its presence.