Treatise on Poisons by Sir Robert Christison
CHAPTER III.
1047 words | Chapter 63
OF POISONING WITH THE MINERAL ACIDS.
Of the mineral acids, the most important, because the most common, are
_sulphuric_, _hydrochloric_, and _nitric_ acids. They are remarkably
similar in their effects on the animal economy. Phosphoric acid is of
much less consequence, and will be noticed cursorily.
Sulphuric acid (_vitriolic acid_, _vitriol_—_oil of vitriol_),
hydrochloric acid (_muriatic acid_,—_spirit of salt_) and nitric acid
(_aqua-fortis_), have been long known to be possessed of very energetic
properties; and consequently cases of poisoning with them have often
been observed. The instances of the kind hitherto published have been
chiefly the result of suicide; a considerable number have originated in
accident; and, however extraordinary it may appear, a few have been
cases of murder. Tartra, in an excellent memoir on the subject of
poisoning with nitric acid, quotes an instance of a woman having been
poisoned while in a state of intoxication by that acid being mixed with
wine and poured down her throat.[224] Valentini has related the case of
a woman who was killed by frequent doses of sulphuric acid given under
the pretence of administering medicines.[225] In 1829 an hospital
servant was condemned at Strasbourg for trying to murder his wife in
like manner, by first making her ill with tartar-emetic and then giving
her sulphuric acid in syrup, under the pretence of curing her.[226] At
the Aberdeen autumn circuit in 1830 a woman Humphrey was convicted of
murdering her husband by pouring the same acid down his throat while he
lay asleep with his mouth open.[227] On the whole, considering the
powerful taste and excessively acrid properties of these poisons, it is
probable that they will seldom be resorted to for the purpose of making
away with another person, who is an adult, and in a state of
consciousness. Of late, however, there have been several instances in
our country of murder committed on infants in this barbarous manner. A
woman Malcolm was executed here in 1808 for murdering her own child, an
infant of eighteen months, by pouring sulphuric acid down its
throat;[228] another woman Clark was tried for the same crime at Exeter
in 1822; a man was executed lately at Manchester for murdering in the
same way his son, a child four years and a half old;[229] and the
particulars of an interesting trial will be presently noticed, that of
Overfield, who was executed at Shrewsbury in 1824, for poisoning his
child in the like manner.[230]
In a medico-legal point of view, the mineral acids are interesting on
another account. Of late a new crime has arisen in Britain, the
disfiguring of the countenance by squirting oil of vitriol on it. It
originated in Glasgow, during the quarrels in 1820, between masters and
workmen regarding the rate of wages,[231] and became at last so
frequent, that the Lord Advocate, in applying for an act of Parliament
to extend the English Stabbing and Maiming act to Scotland, added a
clause which renders the offence now alluded to capital. In 1828 a woman
Macmillan was tried here and condemned under that act.[232] The crime
afterwards became common in England. Three cases were noticed in the
newspapers as having occurred in London, in November, 1828; and two
others near Manchester in the spring of 1829. It is now much less
frequent.
The mineral acids are also very interesting on scientific grounds. They
afford the purest examples of true corrosive poisons, their poisonous
effects depending entirely on the organic injury they occasion in the
textures to which they are applied. It is of use to set out, in
investigating the effects of poisons, by determining the phenomena
presented under such circumstances. When made aware of the rapidity with
which other irritating poisons prove fatal, and the slight signs they
commonly leave of their operation, one cannot fail to be struck with
discovering what the animal frame will sometimes endure from these the
most violent of all irritants, and nevertheless recover.
In laying down the mode of determining by chemical evidence a case of
supposed poisoning with any of the three mineral acids mentioned above,
it will be unnecessary to notice any of their chemical properties,
except those from which their medico-legal tests are derived.
The only common properties that require notice are, their power of
reddening the vegetable blue colours, for showing which litmus-paper is
commonly used, and is most convenient: and their power of staining and
corroding all articles of dress, especially such as are made of wool,
hair, and leather. This last property is specified, though a familiar
one, because it always forms important evidence in criminal cases. In
order to give precision to such evidence, it is necessary to remember,
that if the article of dress is a coloured one, it is generally rendered
red by the mineral acids; but that the vegetable acids also will redden
most articles of dress, although they do not corrode them.
I.—OF POISONING WITH SULPHURIC ACID.
Sulphuric acid is extensively employed in very many trades, is used even
for some domestic purposes, and is consequently familiar to every one.
Hence it is the mineral acid which has been most commonly used as a
poison, especially for committing suicide. Of 35 cases of poisoning with
the mineral acids which occurred in England in the years 1837 and 1838,
32 were caused by this acid (p. 90).
SECTION I.—_Of the Tests for Sulphuric Acid._
Sulphuric acid is known as a poison chiefly in the form of the
concentrated commercial acid. But a few cases of poisoning have also
been produced by blue-liquor or the solution of indigo in strong
sulphuric acid; and one instance[233] has been recorded of poisoning
with the aromatic sulphuric acid of the Pharmacopœias, which is an
infusion of aromatics in a mixture of sulphuric acid, ether and alcohol.
In the following remarks on its tests, it will be sufficient to consider
it _first_ in the concentrated form,—_secondly_, in a state of simple
dilution,—and _thirdly_, when mixed with various impurities, more
especially with vegetable and animal matter. The acid solution of indigo
may be known by the tests for the concentrated acid, and its blue
colour, removable by a solution of chlorine; and the aromatic sulphuric
acid may be distinguished by its odour and the tests for the diluted
acid.
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