SULPHURIC ACID--HYDROCHLORIC ACID--NITRIC ACID--ACETIC
ACID--AMMONIA--POTASH--SODA--NEUTRAL SODIUM, POTASSIUM, AND AMMONIUM
SALTS.
I.--Sulphuric Acid.
§ 51. Sulphuric acid (hydric sulphate, oil of vitriol, H₂SO₄) occurs in
commerce in varying degrees of strength or dilution; the strong
sulphuric acid of the manufacturer, containing 100 per cent. of real
acid (H₂SO₄), has a specific gravity of 1·850. The ordinary brown acid
of commerce, coloured by organic matter and holding in solution metallic
impurities, chiefly lead and arsenic, has a specific gravity of about
1·750; and contains 67·95 of anhydrous SO₃ = 85·42 of hydric sulphate.
There are also weaker acids used in commerce, particularly in
manufactories in which sulphuric acid is made, for special purposes
without rectification. The British Pharmacopœia sulphuric acid is
directed to be of 1·843 specific gravity, which corresponds to 78·6 per
cent. sulphuric anhydride, or 98·8 per cent. of hydric sulphate. The
dilute sulphuric acid of the pharmacopœia should have a specific gravity
of 1·094, and is usually said to correspond to 10·14 per cent. of
anhydrous sulphuric acid; but, if Ure’s Tables are correct, such equals
11·37 per cent.
The general characters of sulphuric acid are as follows:--When pure, it
is a colourless, or, when impure, a dark brown to black, oily liquid,
without odour at common temperatures, of an exceedingly acid taste,
charring most organic tissues rapidly, and, if mixed with water,
evolving much heat. If 4 parts of the strong acid are mixed with 1 part
of water at 0°, the mixture rises to a heat of 100°; a still greater
heat is evolved by mixing 75 parts of acid with 27 of water.
Sulphuric acid is powerfully hygroscopic--3 parts will, in an ordinary
atmosphere, increase to nearly 4 in twenty-four hours; in common with
all acids, it reddens litmus, yellows cochineal, and changes all
vegetable colours. There is another form of sulphuric acid, extensively
used in the arts, known under the name of “Nordhausen sulphuric acid,”
“fuming acid,” formula H₂S₂O₄. This acid is produced by the distillation
of dry ferrous sulphate, at a nearly white heat--either in earthenware
or in green glass retorts; the distillate is received in sulphuric acid.
As thus manufactured, it is a dark fuming liquid of 1·9 specific
gravity, and boiling at 53°. When artificially cooled down to 0°, the
acid gradually deposits crystals, which consist of a definite compound
of 2 atoms of anhydrous sulphuric acid and 1 atom of water. There is
some doubt as to the molecular composition of Nordhausen acid; it is
usually considered as hydric sulphate saturated with sulphur dioxide.
This acid is manufactured chiefly in Bohemia, and is used, on a large
scale, as a solvent for alizarine.
§ 52. =Sulphur Trioxide, or Sulphuric Anhydride= (SO₃), itself may be
met with in scientific laboratories, but is not in commerce. Sulphur
trioxide forms thin needle-shaped crystals, arranged in feathery groups.
Seen in mass, it is white, and has something the appearance of asbestos.
It fuses to a liquid at about 18°, boils at 35°, but, after this
operation has been performed, the substance assumes an allotropic
condition, and then remains solid up to 100°; above 100° it melts,
volatilises, and returns to its normal condition. Sulphuric anhydride
hisses when it is thrown into water, chemical combination taking place
and sulphuric acid being formed. Sulphur trioxide is excessively
corrosive and poisonous.
Besides the above forms of acid, there is an officinal preparation
called “Aromatic Sulphuric Acid,” made by digesting sulphuric acid,
rectified spirit, ginger, and cinnamon together. It contains 10·19 per
cent. of SO₃, alcohol, and principles extracted from cinnamon and
ginger.
§ 53. Sulphuric acid, in the free state, may not unfrequently be found
in nature. The author has had under examination an effluent water from a
Devonshire mine, which contained more than one grain of free sulphuric
acid per gallon, and was accused, with justice, of destroying the fish
in a river. It also exists in large quantities in volcanic springs. In a
torrent flowing from the volcano of Parcé, in the Andes, Boussingault
calculated that 15,000 tons of sulphuric acid and 11,000 tons of
hydrochloric acid were yearly carried down. In the animal and vegetable
kingdom, sulphuric acid exists, as a rule, in combination with bases,
but there is an exception in the saliva of the _Dolium galea_, a
Sicilian mollusc.
§ 54. =Statistics.=--When something like 900,000 tons of sulphuric acid
are produced annually in England alone, and when it is considered that
sulphuric acid is used in the manufacture of most other acids, in the
alkali trade, in the manufacture of indigo, in the soap trade, in the
manufacture of artificial manure, and in a number of technical
processes, there is no cause for surprise that it should be the annual
cause of many deaths.
The number of deaths from sulphuric acid will vary, other things being
equal, in each country, according to the manufactures in that country
employing sulphuric acid. The number of cases of poisoning in England
and Wales for ten years is given in the following table:--
DEATHS FROM SULPHURIC ACID IN ENGLAND AND WALES FOR THE TEN YEARS ENDING
1892.
ACCIDENT OR NEGLIGENCE.
Ages, 1-5 5-15 15-25 25-65 65 & Total
upwards
Males, 11 4 2 14 2 33
Females, 4 ... 2 3 ... 9
---------------------------------------------
Totals, 15 4 4 17 2 42
---------------------------------------------
SUICIDE.
Ages, 15-25 25-65 Total
Males, 4 25 29
Females, 5 19 24
---------------------------------
Totals 9 44 53
---------------------------------
During the ten years, no case of murder through sulphuric acid is on
record; hence the total deaths, as detailed in the tables, amount to 95,
or a little over 9 a year.
Falck,[64] in comparing different countries, considers the past
statistics to show that in France sulphuric acid has been the cause of
4·5 to 5·5 per cent. of the total deaths from poison, and in England 5·9
per cent. In England, France, and Denmark, taken together, 10·8, Prussia
10·6; while in certain cities, as Berlin and Vienna, the percentages are
much higher--Vienna showing 43·3 per cent., Berlin 90 per cent.
[64] _Lehrbuch der praktischen Toxicologie_, p. 54.
§ 55. =Accidental, Suicidal, and Criminal Poisoning.=--Deaths from
sulphuric acid are, for the most part, accidental, occasionally
suicidal, and, still more rarely, criminal. In 53 out of 113 cases
collected by Böhm, in which the cause of the poisoning could, with fair
accuracy, be ascertained, 45·3 per cent. were due to accident, 30·2 were
suicidal, and 24·5 per cent. were cases of criminal poisoning, the
victims being children.
The cause of the comparatively rare use of sulphuric acid by the
poisoner is obvious. First of all, the acid can never be mixed with food
without entirely changing its aspect; next, it is only in cases of
insensibility or paralysis that it could be administered to an adult,
unless given by force, or under very exceptional circumstances; and
lastly, the stains on the mouth and garments would at once betray, even
to uneducated persons, the presence of something wrong. As an agent of
murder, then, sulphuric acid is confined in its use to young children,
more especially to the newly born.
There is a remarkable case related by Haagan,[65] in which an adult man,
in full possession of his faculties, neither paralysed nor helpless, was
murdered by sulphuric acid. The wife of a day-labourer gave her husband
drops of sulphuric acid on sugar, instead of his medicine, and finally
finished the work by administering a spoonful of the acid. The spoon was
carried well to the back of the throat, so that the man took the acid at
a gulp. 11 grms. (171 grains) of sulphuric acid, partly in combination
with soda and potash, were separated from his stomach.
[65] Gross: _Die Strafrechtspflege in Deutschland_, 4, 1861, Heft I. S.
181.
Accidental poisoning is most common among children. The oily,
syrupy-looking sulphuric acid, when pure, may be mistaken for glycerin
or for syrup; and the dark commercial acid might, by a careless person,
be confounded with porter or any dark-looking medicine.
Serious and fatal mistakes have not unfrequently arisen from the use of
injections. Deutsch[66] relates how a midwife, in error, administered to
mother and child a sulphuric acid clyster; but little of the fluid could
in either case have actually reached the rectum, for the mother
recovered in eight days, and in a little time the infant was also
restored to health. Sulphuric acid has caused death by injections into
the vagina. H. C. Lombard[67] observed a case of this kind, in which a
woman, aged thirty, injected half a litre of sulphuric acid into the
vagina, for the purpose of procuring abortion. The result was not
immediately fatal, but the subsequent inflammation and its results so
occluded the natural passage that the birth became impossible, and a
Cæsarean section extracted a dead child, the mother also dying.
[66] _Preuss. Med. Vereins-Zeitung_, 1848, No. 13.
[67] _Journ. de Chim. Méd._, tom. vii., 1831.
An army physician prescribed for a patient an emollient clyster. Since
it was late at night, and the apothecary in bed, he prepared it himself;
but not finding linseed oil, woke the apothecary, who took a bottle out
of one of the recesses and placed it on the table. The bottle contained
sulphuric acid; a soldier noticed a peculiar odour and effervescence
when the syringe was charged, but this was unheeded by the doctor. The
patient immediately after the operation suffered the most acute agony,
and died the following day; before his death, the bedclothes were found
corroded by the acid, and a portion of the bowel itself came away.[68]
[68] Maschka’s _Handbuch_, p. 86; _Journal de Chimie Médicale_, t. i.
No. 8, 405, 1835.
§56. =Fatal Dose.=--The amount necessary to kill an adult man is not
strictly known; fatality so much depends on the concentration of the
acid and the condition of the person, more especially whether the
stomach is full or empty, that it will be impossible ever to arrive at
an accurate estimate. Christison’s case, in which 3·8 grms. (60 grains)
of concentrated acid killed an adult, is the smallest lethal dose on
record. Supposing that the man weighed 68½ kilo. (150 lbs.), this would
be in the proportion of ·05 grm. per kilo. There is also the case of a
child of one year, recorded by Taylor, in which 20 drops caused death.
If, however, it were asked in a court of law what dose of concentrated
sulphuric acid would be dangerous, the proper answer would be: so small
a quantity as from 2 to 3 drops of the strong undiluted acid might cause
death, more especially if conveyed to the back of the throat; for if it
is improbable that on such a supposition death would be sudden, yet
there is a possibility of permanent injury to the gullet, with the
result of subsequent contraction, and the usual long and painful
malnutrition thereby induced. It may be laid down, therefore, that all
quantities, even the smallest, of the _strong undiluted acid_ come under
the head of hurtful, noxious, and injurious.
§ 57. =Local Action of Sulphuric Acid.=--The action of the acid on
living animal tissues has been studied of late by C. Ph. Falck and L.
Vietor.[69] Concentrated acid precipitates albumen, and then redissolves
it; fibrin swells and becomes gelatinous; but if the acid is weak
(_e.g._, 4 to 6 per cent.) it is scarcely changed. Muscular fibre is at
first coloured amber-yellow, swells to a jelly, and then dissolves to a
red-brown turbid fluid. When applied to the mucous membrane of the
stomach, the mucous tissue and the muscular layer beneath are coloured
white, swell, and become an oily mass.
[69] _Deutsche Klinik_, 1864, Mo. 1-32, and Vietor’s
_Inaugur.-Dissert._, Marburg, 1803.
When applied to a rabbit’s ear,[70] the parenchyma becomes at first pale
grey and semi-transparent at the back of the ear; opposite the drop of
acid appear spots like grease or fat drops, which soon coalesce. The
epidermis with the hair remains adherent; the blood-vessels are narrowed
in calibre, and the blood, first in the veins, and then in the arteries,
is coloured green and then black, and fully coagulates. If the drop,
with horizontal holding of the ear, is dried in, an inflammatory zone
surrounds the burnt spot in which the blood circulates; but there is
complete stasis in the part to which the acid has been applied. If the
point of the ear is dipped in the acid, the cauterised part rolls
inwards; after the lapse of eighteen hours the part is brown and
parchment-like, with scattered points of coagulated blood; then there is
a slight swelling in the healthy tissues, and a small zone of redness;
within fourteen days a bladder-like greenish-yellow scab is formed, the
burnt part itself remaining dry. The vessels from the surrounding zone
of redness gradually penetrate towards the cauterised spot, the fluid
in the bleb becomes absorbed, and the destroyed tissues fall off in the
form of a crust.
[70] Samuel, _Entzündung u. Brand, in Virchow’s Archiv f. Path. Anat._,
Bd. 51, Hft. 1 u. 2, S. 41, 1870.
The changes that sulphuric acid cause in blood are as follows: the
fibrin is at first coagulated and then dissolved, and the colouring
matter becomes of a black colour. These changes do not require the
strongest acid, being seen with an acid of 60 per cent.
§ 58. The action of the acid on various non-living matters is as
follows: poured on all vegetable earth, there is an effervescence,
arising from decomposition of carbonates; any grass or vegetation
growing on the spot is blackened and dies; an analysis of the layer of
earth, on which the acid is poured, shows an excess of sulphates as
compared with a similar layer adjacent; the earth will only have an acid
reaction, if there has been more than sufficient acid to neutralise all
alkalies and alkaline earths.
Wood almost immediately blackens, and the spot remains moist.
Spots on paper become quickly dark, and sometimes exhibit a play of
colours, such as reddish-brown; ultimately the spot becomes very black,
and holes may be formed; even when the acid is dilute, the course is
very similar, for the acid dries in, until it reaches a sufficient
degree of concentration to attack the tissue. I found small drops of
sulphuric acid on a brussels carpet, which had a red pattern on a dark
green ground with light green flowers, act as follows: the spots on the
red at the end of a few hours were of a dark maroon colour, the green
was darkened, and the light green browned; at the end of twenty-four
hours but little change had taken place, nor could any one have guessed
the cause of the spots without a close examination. Spots of the strong
acid on thin cotton fabrics rapidly blackened, and actual holes were
formed in the course of an hour; the main difference to the naked eye,
between the stains of the acid and those produced by a red-hot body, lay
in the moistness of the spots. Indeed, the great distinction, without
considering chemical evidence, between recent burns of clothing by
sulphuric acid and by heat, is that in the one case--that of the
acid--the hole or spot is very moist; in the other very dry. It is easy
to imagine that this distinction may be of importance in a legal
investigation.
Spots of acid on clothing fall too often under the observation of all
those engaged in practical chemical work. However quickly a spot of acid
is wiped off, unless it is immediately neutralised by ammonia, it
ultimately makes a hole in the cloth; the spot, as a rule, whatever the
colour of the cloth, is of a blotting-paper red.
Sulphuric acid dropped on iron, attacks it, forming a sulphate, which
may be dissolved out by water. If the iron is exposed to the weather
the rain may wash away all traces of the acid, save the corrosion; but
it would be under those circumstances impossible to say whether the
corrosion was due to oxidation or a solvent.
To sum up briefly: the characters of sulphuric acid spots on organic
matters generally are black, brown, or red-coloured destructions of
tissue, moisture, acid-reaction (often after years), and lastly the
chemical evidence of sulphuric acid or sulphates in excess.
=Caution necessary in judging of Spots, &c.=--An important case, related
by Maschka, shows the necessity of great caution in interpreting
results, unless all the circumstances of a case be carefully collated. A
live coal fell on the bed of a weakly infant, five months old. The child
screamed, and woke the father, who was dozing by the fire; the man, in
terror, poured a large pot of water on the child and burning bed. The
child died the following day.
A _post-mortem_ examination showed a burn on the chest of the infant 2
inches in length. The tongue, pharynx, and gullet were all healthy; in
the stomach a patch of mucous membrane, about half an inch in extent,
was found to be brownish, friable, and very thin. A chemical examination
showed that the portion of the bed adjacent to the burnt place contained
free sulphuric acid. Here, then, was the following evidence: the sudden
death of a helpless infant, a carbonised bed-cover with free sulphuric
acid, and, lastly, an appearance in the stomach which, it might be said,
was not inconsistent with sulphuric acid poisoning. Yet a careful
sifting of the facts convinced the judges that no crime had been
committed, and that the child’s death was due to disease. Afterwards,
experiment showed that if a live coal fall on to any tissue, and be
drenched with water, free sulphuric acid is constantly found in the
neighbourhood of the burnt place.
§ 59. =Symptoms.=--The symptoms may be classed in two divisions,
viz.:--1. External effects of the acid. 2. Internal effects and symptoms
arising from its interior administration.
1. =External Effects.=--Of late years several instances have occurred in
which the acid has been used criminally to cause disfiguring burns of
the face. The offence has in all these cases been committed by women,
who, from motives of revengeful jealousy, have suddenly dashed a
quantity of the acid into the face of the object of their resentment. In
such cases, the phenomena observed are not widely different from those
attending scalds or burns from hot neutral fluids. There is destruction
of tissue, not necessarily deep, for the acid is almost immediately
wiped off; but if any should reach the eye, inflammation, so acute as to
lead to blindness, is the probable consequence. The skin is coloured at
first white, at a later period brown, and part of it may be, as it were,
dissolved. If the tract or skin touched by the acid is extensive, death
may result. The inflammatory processes in the skin are similar to those
noticed by Falck and Vietor in their experiments, already detailed (p.
79).
=Internal Effects of Acids generally.=--It may not be out of place,
before speaking of the internal effects of sulphuric acid, to make a few
remarks upon the action of acids generally. This action differs
according to the kind of animal; at all events, there is a great
difference between the action of acids on the herb-eating animals and
the carnivora; the latter bear large doses of acids well, the former
ill. For instance, the rabbit, if given a dose of any acid not
sufficient to produce local effects but sufficient to affect its
functions, will soon become paralysed and lie in a state of stupor, as
if dead; the same dose per kilo. will not affect the dog. The reason for
this is that the blood of the dog is able to neutralise the acid by
ammonia, and that the blood of the rabbit is destitute of this property.
Man is, in this respect, nearer to the dog than to the plant-eaters.
Stadelmann has shown that a man is able to ingest large relative doses
of oxybutyric acid, to neutralise the acid by ammonia, and to excrete it
by means of the kidneys as ammonium butyrate.
Acids, however, if given in doses too great to be neutralised, alike
affect plant- and flesh-eaters; death follows in all cases before the
blood becomes acid. Salkowsky[71] has, indeed, shown that the effect of
lessening the alkalinity of the blood by giving a rabbit food from which
it can extract no alkali produces a similar effect to the actual dosing
with an acid.
[71] Virchow’s _Archiv_, Bd. 58, 1.
2. =Internal Effects of Sulphuric Acid.=--When sulphuric acid is taken
internally, the acute and immediate symptom is pain. This, however, is
not constant, since, in a few recorded cases, no complaint of pain has
been made; but these cases are exceptional; as a rule, there will be
immediate and great suffering. The tongue swells, the throat is also
swollen and inflamed, swallowing of saliva even may be impossible. If
the acid has been in contact with the epiglottis and vocal apparatus,
there may be spasmodic croup and even fatal spasm of the glottis.
The acid, in its passage down the gullet, attacks energetically the
mucous membrane and also the lining of the stomach; but the action does
not stop there, for Lesser found in eighteen out of twenty-six cases (69
per cent.) that the corrosive action extended as far as the duodenum.
There is excessive vomiting and retching; the matters vomited are acid,
bloody, and slimy; great pieces of mucous membrane may be in this way
expelled, and the whole of the lining membrane of the gullet may be
thrown up entire. The bowels are, as a rule, constipated, but
exceptionally there has been diarrhœa; the urine is sometimes retained;
it invariably contains an excess of sulphates and often albumen, with
hyaline casts of the uriniferous tubes. The pulse is small and frequent,
the breathing slow, the skin very cold and covered with sweat; the
countenance expresses great anxiety, and the extremities may be affected
with cramps or convulsions. Death may take place within from twenty-four
to thirty-six hours, and be either preceded by dyspnœa or by
convulsions; consciousness is, as a rule, maintained to the end.
There are also more rapid cases than the above; a large dose of
sulphuric acid taken on an empty stomach may absolutely dissolve it, and
pass into the peritoneum; in such a case there is really no difference
in the symptoms between sudden perforation of the stomach from disease,
a penetrating wound of the abdomen, and any other sudden fatal lesion of
the organs in the abdominal cavity (for in all these instances the
symptoms are those of pure collapse); the patient is ashen pale, with
pulse quick and weak, and body bathed in cold sweat, and he rapidly
dies, it may be without much complaint of local pain.
If the patient live longer than twenty-four hours, the symptoms are
mainly those of inflammation of the whole mucous tract, from the mouth
to the stomach; and from this inflammation the patient may die in a
variable period, of from three to eleven days, after taking the poison.
In one case the death occurred suddenly, without any immediately
preceding symptoms rendering imminent death probable. If this second
stage is passed, then the loss of substance in the gullet and in the
stomach almost invariably causes impairment of function, leading to a
slow and painful death. The common sequence is stricture of the gullet,
combined with feeble digestion, and in a few instances stricture of the
pylorus. A curious sequel has been recorded by Mannkopf, viz., obstinate
intercostal neuralgia; it has been observed on the fourth, seventh, and
twenty-second day.
§ 60. =Treatment of Acute Poisoning by the Mineral Acids.=--The
immediate indication is the dilution and neutralisation of the acid. For
this purpose, finely-divided chalk, magnesia, or sodic carbonate may be
used, dissolved or suspended in much water. The use of the stomach-pump
is inadvisable, for the mucous membrane of the gullet may be so corroded
by the acid that the passage of the tube down will do injury; unless the
neutralisation is _immediate_, but little good is effected; hence it
will often occur that the bystanders, if at all conversant with the
matter, will have to use the first thing which comes to hand, such as
the plaster of a wall, &c.; and lastly, if even these rough antidotes
are not to be had, the best treatment is enormous doses of water, which
will dilute the acid and promote vomiting. The treatment of the
after-effects belongs to the province of ordinary medicine, and is based
upon general principles.
§ 61. =Post-mortem Appearances.=[72]--The general pathological
appearances to be found in the stomach and internal organs differ
according as the death is rapid or slow; if the death takes place within
twenty-four hours, the effects are fairly uniform, the differences being
only in degree; while, on the other hand, in those cases which terminate
fatally from the more remote effects of the acid, there is some variety.
It may be well to select two actual cases as types, the one patient
dying from acute poisoning, the other surviving for a time, and then
dying from ulceration and contraction of the digestive tract.
[72] It has been observed that putrefaction in cases of death from
sulphuric acid is slow. Casper suggests this may be due to the
neutralisation of ammonia; more probably it is owing to the antiseptic
properties all mineral acids possess.
A hatter, early in the morning, swallowed a large mouthful of strong
sulphuric acid, a preparation which he used in his work--(whether the
draught was taken accidentally or suicidally was never known). He died
within two hours. The whole tongue was sphacelated, parts of the mucous
membrane being dissolved; the inner surface of the gullet, as well as
the whole throat, was of a grey-black colour; the mucous membrane of the
stomach was coal-black, and so softened that it gave way like
blotting-paper under the forceps, the contents escaping into the cavity
of the abdomen. The peritoneum was also blackened as if burnt; probably
there had been perforation of the stomach during life; the mucous
membrane of the duodenum was swollen, hardened, and looked as if it had
been boiled; while the blood was of a cherry-red colour, and of the
consistence of a thin syrup. The rest of the organs were healthy; a
chemical research on the fluid which had been collected from the
stomach, gullet, and duodenum showed that it contained 87·25 grains of
free sulphuric acid.[73]
[73] Casper, vol. ii. case 194.
This is, perhaps, the most extreme case of destruction on record; the
cause of the unusually violent action is referable to the acid acting on
an empty stomach. It is important to note that even with this extensive
destruction of the stomach, life was prolonged for two hours.
The case I have selected to serve as a type of a chronic but fatal
illness produced from poisoning by sulphuric acid is one related by
Oscar Wyss. A cook, thirty-four years of age, who had suffered many
ailments, drank, on the 6th of November 1867, by mistake, at eight
o’clock in the morning, two mouthfuls of a mixture of 1 part of
sulphuric acid and 4 of water. Pain in the stomach and neck, and
vomiting of black masses, were the immediate symptoms, and two hours
later he was admitted into the hospital in a state of collapse, with
cold extremities, cyanosis of the face, &c. Copious draughts of milk
were given, and the patient vomited much, the vomit still consisting of
black pultaceous matters, in which, on a microscopical examination,
could be readily detected columnar epithelium of the stomach and mucous
tissue elements. The urine was of specific gravity 1·033,
non-albuminous; on analysis it contained 3·388 grms. of combined
sulphuric acid.
On the second day there was some improvement in the symptoms; the urine
contained 1·276 grm. of combined sulphuric acid; on the third day 2·665
grms. of combined sulphuric acid; and on the tenth day the patient
vomited up a complete cast of the mucous membrane of the gullet. The
patient remained in the hospital, and became gradually weaker from
stricture of the gullet and impairment of the digestive powers, and
died, two months after taking the poison, on the 5th of January 1868.
The stomach was found small, contracted, with many adhesions to the
pancreas and liver; it was about 12 centimetres long (4·7 inches), and
from 2 to 2·5 centimetres (·7 to ·9 inch) broad, contracted to somewhat
the form of a cat’s intestine; there were several transverse rugæ; the
walls were thickened at the small curvature, measurements giving 5 mm.
(·19 inch) in the middle, and beyond about 2·75 mm. (·11 inch); in the
upper two-thirds the lumen was so contracted as scarcely to admit the
point of the little finger. The inner surface was covered with a layer
of pus, with no trace of mucous tissue, and was everywhere pale red,
uneven, and crossed by cicatricial bands. In two parts, at the greater
curvature, the mucous surface was strongly injected in a ring-like form,
and in the middle of the ring was a deep funnel-shaped ulcer; a part of
the rest of the stomach was strongly injected and scattered over with
numerous punctiform, small, transparent bladders. The gullet was
contracted at the upper part (just below the epiglottis) from 20 to 22
mm. (·78 to ·86 inch) in diameter; it then gradually widened to measure
about 12 mm. (·47 inch) at the diaphragm; in the neighbourhood of the
last contraction the tissue was scarred, injected, and ulcerated; there
were also small abscesses opening into this portion of the gullet.
E. Fraenkel and F. Reiche[74] have studied the effects of sulphuric acid
on the kidney. In rapid cases they find a wide-spread coagulation of the
epithelium in the convoluted and straight urinary canaliculi, with
destruction of the kidney parenchyma, but no inflammation.
[74] Virchow’s _Archiv_, Bd. 131, f. 130.
§ 62. The museums of the different London hospitals afford excellent
material for the study of the effects of sulphuric acid on the pharynx,
gullet, and stomach; and it may be a matter of convenience to students
if the more typical examples at these different museums be noticed in
detail, so that the preparations themselves may be referred to.
_In St. Bartholomew’s Museum_, No. 1942, is an example of excessive
destruction of the stomach by sulphuric acid. The stomach is much
contracted, and has a large aperture with ragged edges; the mucous
membrane is thickened, charred, and blackened.
No. 1941, in the same museum, is the stomach of a person who died
from a large dose of sulphuric acid. When recent, it is described as
of a deep red colour, mottled with black; appearances which, from
long soaking in spirit, are not true at the present time; but the
rough, shaggy state of the mucous tissue can be traced; the gullet
and the pylorus appear the least affected.
_St. George’s Hospital_, ser. ix., 146, 11 and 43, e.--The pharynx
and œsophagus of a man who was brought into the hospital in a state
of collapse, after a large but unknown dose of sulphuric acid. The
lips were much eroded, the mucous membrane of the stomach, pharynx,
and œsophagus show an extraordinary shreddy condition; the lining
membrane of the stomach is much charred, and the action has extended
to the duodenum; the muscular coat is not affected.
_Guy’s Hospital_, No. 1799.--A preparation showing the mucous
membrane of the stomach entirely denuded. The organ looks like a
piece of thin paper.
No. 1799²⁰. The stomach of a woman who poisoned herself by drinking
a wine-glassful of acid before breakfast. She lived eleven days. The
main symptoms were vomiting and purging, but there was no complaint
of pain. There is extensive destruction of mucous membrane along the
lesser curvature and towards the pyloric extremity; a portion of the
mucous membrane is floating as a slough.
No. 1799²⁵ is the gullet and stomach of a man who took about 3
drachms of the strong acid. He lived three days without much
apparent suffering, and died unexpectedly. The lining membrane of
the œsophagus has the longitudinal wrinkles or furrows so often,
nay, almost constantly, met with in poisoning by the acids. The
mucous tissue of the stomach is raised in cloudy ridges, and
blackened.
No. 1799³⁵ is a wonderfully entire cast of the gullet from a woman
who swallowed an ounce of sulphuric acid, and is said, according to
the catalogue, to have recovered.
_University College._--In this museum will be found an exquisite
preparation of the effects of sulphuric acid. The mucous membrane of
the œsophagus is divided into small quadrilateral areas by
longitudinal and transverse furrows; the stomach is very brown, and
covered with shreddy and filamentous tissue; the brown colour is
without doubt the remains of extravasated and charred blood.
No. 6201 is a wax cast representing the stomach of a woman who died
after taking a large dose of sulphuric acid. A yellow mass was found
in the stomach; there are two perforations, and the mucous membrane
is entirely destroyed.
§ 63. =Chronic Poisoning by Sulphuric Acid.=--Weiske[75] has
experimentally proved that lambs, given for six months small doses of
sulphuric acid, grow thin, and their bones, with the exception of the
bones of the head and the long bones, are poor in lime salts, the
muscles also are poor in the same constituents. Kobert[76] thinks that
drunkards on the continent addicted to “Schnaps,” commonly a liquid
acidified with sulphuric acid to give it a sharp taste, often show
typical chronic sulphuric acid poisoning.
[75] H. Weiske, _Journ. f. Landwirthsch._, 1887, 417.
[76] _Lehrbuch der Intoxicationen_, S. 210.
Detection and Estimation of Free Sulphuric Acid.
§ 64. The general method of separating the mineral acids is as follows:
the tissues, or matters, are soaked in distilled water for some time. If
no free acid is present, the liquid will not redden litmus-paper, or
give an acid reaction with any of the numerous tinctorial agents in use
by the chemist for the purposes of titration. After sufficient digestion
in water, the liquid extract is made up to some definite bulk and
allowed to subside. Filtration is unnecessary. A small fractional part
(say, for example, should the whole be 250 c.c., 1/100th or 2·5 c.c.) is
taken, and using as an indicator cochineal or phenolphthalein, the total
acidity is estimated by a decinormal solution of soda. By this
preliminary operation, some guide for the conduct of the future more
exact operations is obtained. Should the liquid be very acid, a small
quantity of the whole is to be now taken, but if the acidity is feeble,
a larger quantity is necessary, and sufficient quinine then added to fix
the acid--100 parts of sulphuric acid are saturated by 342 parts of
quinine monohydrate. Therefore, on the supposition that all the free
acid is sulphuric, it will be found sufficient to add 3·5 parts of
quinine for every 1 part of acid, estimated as sulphuric, found by the
preliminary rough titration; and as it is inconvenient to deal with
large quantities of alkaloid, a fractional portion of the liquid extract
(representing not more than 50 mgrms. of acid) should be taken, which
will require 175 mgrms. of quinine.
On addition of the quinine, the neutralised liquid is evaporated to
dryness, or to approaching dryness, and then exhausted by strong
alcohol. The alcoholic extract is, after filtration, dried up, and the
quinine sulphate, nitrate, or hydrochlorate, as the case may be,
filtered off and extracted by boiling water, and precipitated by
ammonia, the end result being quinine hydrate (which may be filtered off
and used again for similar purposes) and a sulphate, nitrate or chloride
of ammonia in solution. It therefore remains to determine the nature and
quantity of the acids now combined with ammonia. The solution is made up
to a known bulk, and portions tested for chlorides by nitrate of silver,
and for nitrates by the copper or the ferrous sulphate test. If
sulphuric acid is present, there will be a precipitate of barium
sulphate, which, on account of its density and insolubility in nitric or
hydrochloric acids, is very characteristic. For estimating the sulphuric
acid thus found, it will only be necessary to take a known bulk of the
same liquid, heat it to boiling after acidifying by hydrochloric acid,
and then add a sufficient quantity of baric chloride solution. Unless
this exact process is followed, the analyst is likely to get a liquid
which refuses to filter clear, but if the sulphate be precipitated from
a hot liquid, it usually settles rapidly to the bottom of the vessel,
and the supernatant fluid can be decanted clear; the precipitate is
washed by decantation, and ultimately collected on a filter, dried, and
weighed.
The sulphate of baryta found, multiplied by ·3434, equals the sulphuric
anhydride.
The older process was to dissolve the free sulphuric acid out by
alcohol. As is well known, mineral sulphates are insoluble in, and are
precipitated by, alcohol, whereas sulphuric acid enters into solution.
The most valid objection, as a quantitative process, to the use of
alcohol, is the tendency which all mineral acids have to unite with
alcohol in organic combination, and thus, as it were, to disappear; and,
indeed, results are found, by experiment, to be below the truth when
alcohol is used. This objection does not hold good if either merely
qualitative evidence, or a fairly approximate quantation, is required.
In such a case, the vomited matters, the contents of the stomach, or a
watery extract of the tissues, are evaporated to a syrup, and then
extracted with strong alcohol and filtered; a little phenolphthalein
solution is added, and the acid alcohol exactly neutralised by an
alcoholic solution of clear decinormal or normal soda. According to the
acidity of the liquid, the amount used of the decinormal or normal soda
is noted, and then the whole evaporated to dryness, and finally heated
to gentle redness. The alkaline sulphate is next dissolved in very
dilute hydrochloric acid, and the solution precipitated by chloride of
barium in the usual way. The quantitative results, although low, would,
in the great majority of cases, answer the purpose sufficiently.
A test usually enumerated, Hilger’s test for mineral acid, may be
mentioned. A liquid, which contains a very minute quantity of mineral
acid, becomes of a blue colour (or, if 1 per cent. or above, of a green)
on the addition of a solution of methyl aniline violet; but this test,
although useful in examining vinegars (see “Foods,” p. 519), is not of
much value in toxicology, and the quinine method for this purpose meets
every conceivable case, both for qualitative and quantitative purposes.
§ 65. =The Urine.=--Although an excess of sulphates is found constantly
in the urine of persons who have taken large doses of sulphuric acid,
the latter has never been found in that liquid in a free state, so that
it will be useless to search for free acid. It is, therefore, only
necessary to add HCl to filter the fluid, and precipitate direct with an
excess of chloride of barium. It is better to operate in this manner
than to burn the urine to an ash, for in the latter case part of the
sulphates, in the presence of phosphates, are decomposed, and, on the
other hand, any organic sulphur combinations are liable to be estimated
as sulphates.
It may also be well to pass chlorine gas through the same urine which
has been treated with chloride of barium, and from which the sulphate
has been filtered off. The result of this treatment will be a second
precipitate of sulphate derived from sulphur, in a different form of
combination than that of sulphate.
The greatest amount of sulphuric acid as mineral and organic sulphate is
separated, according to Mannkopf[77] and Schultzen,[78] within five
hours after taking sulphuric acid; after three days the secretion, so
far as total sulphates is concerned, is normal.
[77] “Toxicologie der Schwefelsäure,” _Wiener med. Wochen._, 1862, 1863.
[78] _Archiv. f. Anatom. u. Physiol._, 1864.
The normal amount of sulphuric acid excreted daily, according to
Thudichum, is from 1·5 to 2·5 grms., and organic sulphur up to ·2 grm.
in the twenty-four hours, but very much more has been excreted by
healthy persons.
Lehmann made some observations on himself, and found that, on an animal
diet, he excreted no less than 10·399 grms. of sulphuric acid per day,
while on mixed food a little over 7 grms.; but, as Thudichum justly
observes, this great amount must be referred to individual peculiarity.
The amount of sulphates has a decided relation to diet. Animal food,
although not containing sulphates, yet, from the oxidation of the
sulphur-holding albumen, produces a urine rich in sulphate. Thus Vogel
found that a person, whose daily average was 2·02 grms., yielded 7·3 on
a meat diet. The internal use of sulphur, sulphides, and sulphates,
given in an ordinary medicinal way, is traceable in the urine,
increasing the sulphates. In chronic diseases the amount of sulphates is
decreased, in acute increased.
Finally, it would appear that the determination of sulphates in the
urine is not of much value, _save when the normal amount that the
individual secretes is primarily known_. On the other hand, a low amount
of sulphates in the urine of a person poisoned by sulphuric acid has not
been observed within three days of the taking of the poison, and one can
imagine cases in which such a low result might have forensic importance.
The presence of albumen in the urine has been considered by some a
constant result of sulphuric acid poisoning, but although when looked
for it is usually found, it cannot be considered constant. O.
Smoler,[79] in eighteen cases of various degrees of sulphuric acid
poisoning, found nothing abnormal in the urine. Wyss[80] found in the
later stages of a case indican and pus. E. Leyden and Ph. Munn[81]
always found blood in the urine, as well as albumen, with casts and
cellular elements. Mannkopf[82] found albuminuria in three cases out of
five; in two of the cases there were fibrinous casts; in two the albumen
disappeared at the end of the second or third day, but in one it
continued for more than twenty days. Bamberger[83] has observed an
increased albuminuria, with separation of the colouring matter of the
blood. In this case it was ascribed to the action of the acid on the
blood.
[79] _Archiv der Heilkunde red. v._ E. Wagner, 1869, Hft. 2, S. 181.
[80] _Wiener Medicinal-Halle_, 1861, Jahr. 6, No. 46.
[81] Virchow’s _Archiv f. path. Anat._, 1861. Bd. 22, Hft. 3 u. 4, S.
237.
[82] _Wien. med. Wochenschrift_, 1862, Nro. 35; 1863, Nro. 5.
[83] _Wien. Med.-Halle_, 1864, Nro. 29, 30.
§ 66. =The Blood.=--In Casper’s case, No. 193, the vena cava of a child,
who died within an hour after swallowing a large dose of sulphuric acid,
was filled with a cherry-red, strongly acid-reacting blood. Again,
Casper’s case, No. 200, is that of a young woman, aged 19, who died from
a poisonous dose of sulphuric acid. At the autopsy, four days after
death, the following peculiarities of the blood were thus noted:--“The
blood had an acid reaction, was dark, and had (as is usual in these
cases) a syrupy consistence, while the blood-corpuscles were quite
unchanged. The blood was treated with an excess of absolute alcohol,
filtered, the filtrate concentrated on a water-bath, the residue
exhausted with absolute alcohol, &c. It yielded a small quantity of
sulphuric acid.”
Other similar cases might be noted, but it must not for a moment be
supposed that the mass of the blood contains any free sulphuric acid
during life. The acidity of the blood in the vena cava may be ascribed
to _post-mortem_ endosmosis, the acid passing through the walls of the
stomach into the large vessel.
§ 67. =Sulphates.=--If the acid swallowed should have been entirely
neutralised by antidotes, such as chalk, &c., it becomes of the first
importance to ascertain, as far as possible, by means of a microscopical
examination, the nature of the food remaining in the stomach, and then
to calculate the probable contents in sulphates of the food thus known
to be eaten. It will be found that, with ordinary food, and under
ordinary circumstances, only small percentages of combined sulphuric
acid can be present.
As an example, take the ordinary rations of the soldier, viz.:--12 oz.
of meat, 24 oz. of bread, 16 oz. of potatoes, 8 oz. of other vegetables;
with sugar, salt, tea, coffee, and water. Now, if the whole quantity of
these substances were eaten at a meal, they would not contain more than
from 8 to 10 grains (·5 to ·6 grm.) of anhydrous sulphuric acid, in the
form of sulphates.
So far as the contents of the stomach are concerned, we have only to do
with sulphates introduced in the food, but when once the food passes
further along the intestinal canal, circumstances are altered, for we
have sulphur-holding secretions, which, with ordinary chemical methods,
yield sulphuric acid. Thus, even in the newly-born infant, according to
the analyses of Zweifler, the mineral constituents of meconium are
especially sulphate of lime, with a smaller quantity of sulphate of
potash. The amount of bile which flows into the whole tract of the
intestinal canal is estimated at about half a litre in the twenty-four
hours; the amount of sulphur found in bile varies from ·89 to 3 per
cent., so that in 500 c.c. we might, by oxidising the sulphur, obtain
from 2·2 to 7·5 grms. of sulphuric anhydride.
It is therefore certain that large quantities of organic
sulphur-compounds may be found in the human intestinal canal, for with
individuals who suffer from constipation, the residues of the biliary
secretion accumulate for many days. Hence, if the analyst searches for
sulphates in excretal matters, all methods involving destruction of
organic substances, whether by fire or by fluid-oxidising agents, are
wrong in principle, and there is nothing left save to separate soluble
sulphates by dialysis, or to precipitate direct out of an aqueous
extract.
Again, sulphate of magnesia is a common medicine, and so is sodic
sulphate; a possible medicinal dose of magnesia sulphate might amount to
56·7 grms. (2 oz.), the more usual dose being half that quantity.
Lastly, among the insane there are found patients who will eat
plaster-of-Paris, earth, and similar matters, so that, in special cases,
a very large amount of combined sulphuric acid may be found in the
intestinal tract, without any relation to poisoning by the free acid;
but in such instances it must be rare, indeed, that surrounding
circumstances or pathological evidence will not give a clue to the real
state of affairs.
II.--Hydrochloric Acid.
§ 68. _General Properties._--Hydrochloric acid, otherwise called
_muriatic acid_, _spirit of salt_, is, in a strictly chemical sense, a
pure gas, composed of 97·26 per cent. of chlorine, and 2·74 per cent. of
hydrogen; but, in an ordinary sense, it is a liquid, being a solution of
the gas itself.
Hydrochloric acid is made on an enormous scale in the United Kingdom,
the production being estimated at about a million tons annually.
The toxicology of hydrochloric acid is modern, for we have no evidence
that anything was known of it prior to the middle of the seventeenth
century, when Glauber prepared it in solution, and, in 1772, Priestley,
by treating common salt with sulphuric acid, isolated the pure gas.
The common liquid hydrochloric acid of commerce has a specific gravity
of from 1·15 to 1·20, and contains usually less than 40 parts of
hydrochloric acid in the 100 parts. The strength of pure samples of
hydrochloric acid can be told by the specific gravity, and a very close
approximation, in default of tables, may be obtained by simply
multiplying the decimal figures of the specific gravity by 200. For
example, an acid of 1·20 gravity would by this rule contain 40 per cent.
of real acid, for ·20 × 200 = 40.
The commercial acid is nearly always a little yellow, from the presence
of iron derived from metallic retorts, and usually contains small
quantities of chloride of arsenic,[84] derived from the sulphuric acid;
but the colourless hydrochloric acid specially made for laboratory and
medicinal use is nearly always pure.
[84] Some samples of hydrochloric acid have been found to contain as
much as 4 per cent. of chloride of arsenic, but this is very unusual.
Glenard found as a mean 2·5 grammes, As₂O₃ per kilogramme.
The uses of the liquid acid are mainly in the production of chlorine, as
a solvent for metals, and for medicinal and chemical purposes. Its
properties are briefly as follows:--
It is a colourless or faintly-yellow acid liquid, the depth of colour
depending on its purity, and especially its freedom from iron. The
liquid is volatile, and can be separated from fixed matters and the less
volatile acids by distillation; it has a strong attraction for water,
and fumes when exposed to the air, from becoming saturated with aqueous
vapour. If exposed to the vapour of ammonia, extremely dense clouds
arise, due to the formation of the solid ammonium chloride. The acid,
boiled with a small quantity of manganese binoxide, evolves chlorine.
Dioxide of lead has a similar action; the chlorine may be detected by
its bleaching action on a piece of paper dipped in indigo blue; a little
zinc foil immersed in the acid disengages hydrogen. These two
tests--viz., the production of chlorine by the one, and the production
of hydrogen by the other--separate and reveal the constituent parts of
the acid. Hydrochloric acid, in common with chlorides, gives a dense
precipitate with silver nitrate. The precipitate is insoluble in nitric
acid, but soluble in ammonia; it melts without decomposition. Exposed to
the light, it becomes of a purple or blackish colour. Every 100 parts of
silver chloride are equal to 25·43 of hydrochloric acid, HCl, and to
63·5 parts of the liquid acid of specific gravity 1·20.
The properties of pure hydrochloric acid gas are as follows:--Specific
gravity 1·262, consisting of equal volumes of hydrogen and chlorine,
united without condensation. 100 cubic inches must therefore have a
weight of 39·36 grains. The gas was liquefied by Faraday by means of a
pressure of 40 atmospheres at 10°; it was colourless, and had a less
refractive index than water.
Water absorbs the gas with avidity, 100 volumes of water absorbing
48,000 volumes of the gas, and becoming 142 volumes. The solution has
all the properties of strong hydrochloric acid, specific gravity 1·21.
The dilute hydrochloric acid of the Pharmacopœia should have a specific
gravity of 1·052, and be equivalent to 10·58 per cent. of HCl.
§69. =Statistics of Poisoning by Hydrochloric Acid.=--The following
tables give the deaths, with age and sex distribution, due to
hydrochloric acid for ten years (1883-92):--
DEATHS FROM HYDROCHLORIC ACID IN ENGLAND AND WALES DURING THE TEN YEARS
ENDING 1892.
ACCIDENT OR NEGLIGENCE.
Ages, Under 1-5 5-15 15-25 25-65 65 and Total
1 above
Males, 1 16 2 ... 26 3 48
Females, ... 8 ... ... 9 1 18
----------------------------------------------------
Totals, 1 24 2 ... 35 4 66
----------------------------------------------------
SUICIDE.
Ages, 5-15 15-25 25-65 65 and Total
above
Males, ... 2 73 8 83
Females, 1 8 42 65 116
---------------------------------------
Totals, 1 10 115 73 199
---------------------------------------
In 1889 a solitary case of the murder of a child is on record from
hydrochloric acid; hence, with that addition, the total deaths from
hydrochloric acid amount to 266 in the ten years, or about 26 a year.
§ 70. =Fatal Dose.=--The dose which destroys life is not known with any
accuracy. In two cases, adults have been killed by 14 grms. (half an
ounce) of the commercial acid; but, on the other hand, recovery is
recorded when more than double this quantity has been taken. A girl,
fifteen years of age, died from drinking a teaspoonful of the acid.[85]
[85] _Brit. Med. Journ._, March, 1871.
§ 71. =Amount of Free Acid in the Gastric Juice.=--Hydrochloric acid
exists in the gastric juice. This was first ascertained by Prout[86] in
1824; he separated it by distillation. The observation was afterwards
confirmed by Gmelin,[87] Children,[88] and Braconnot.[89] On the other
hand, Lehmann[90] pointed out that, as the stomach secretion contained,
without doubt, lactic acid, the act of distillation, in the presence of
this lactic acid, would set free hydrochloric acid from any alkaline
chlorides. Blondlot and Cl. Bernard also showed that the gastric juice
possessed no acid which would dissolve oxalate of lime, or develop
hydrogen when treated with iron filings; hence there could not be free
hydrochloric acid which, even in a diluted state, would respond to both
these tests. Then followed the researches of C. Schmidt,[91] who showed
that the gastric secretion of men, of sheep, and of dogs contained more
hydrochloric acid than would satisfy the bases present; and he
propounded the view that the gastric juice does not contain absolutely
free hydrochloric acid, but that it is in loose combination with the
pepsin.
[86] _Philosophical Transactions_, 1824, p. 45.
[87] P. Tiedmann and L. Gmelin, _Die Verdauung nach Versuchen_,
Heidelberg u. Leipsic, 1826, i.
[88] _Annals of Philosophy_, July, 1824.
[89] _Ann. de Chim._ t. lix. p. 348.
[90] _Journal f. prakt. Chemie_, Bd. xl. 47.
[91] Bidder u. Schmidt, _Verdauungs-Säfte_, &c.
The amount of acid in the stomach varies from moment to moment, and
therefore it is not possible to say what the average acidity of gastric
juice is. It has been shown that in the total absence of _free_
hydrochloric acid digestion may take place, because hydrochloric acid
forms a compound with pepsin which acts as a solvent on the food. The
amount of physiologically active acid varies with the food taken. It is
smallest when carbohydrates are consumed, greatest with meat. The
maximum amount that Jaksch found in his researches, when meat was
ingested, was ·09 per cent. of hydrochloric acid. It is probable that
anything above 0·2 per cent. of hydrochloric acid is either abnormal or
owing to the recent ingestion of hydrochloric acid.
§ 72. =Influence of Hydrochloric Acid on Vegetation.=--Hydrochloric acid
fumes, if emitted from works on a large scale, injure vegetation much.
In former years, before any legal obligations were placed upon
manufacturers for the condensing of the volatile products, the nuisance
from this cause was great. In 1823, the duty on salt being repealed by
the Government, an extraordinary impetus was given to the manufacture of
hydrochloric acid, and since all the volatile products at that time
escaped through short chimneys into the air, a considerable area of land
round the works was rendered quite unfit for growing plants. The present
law on the subject is, that the maximum quantity of acid escaping shall
not exceed 2 grains per cubic foot of the air, smoke, or chimney gases;
and, according to the reports of the alkali inspectors, the condensation
by the improved appliances is well within the Act, and about as perfect
as can be devised.
It appears from the reports of the Belgian Commission in 1855, when
virtually no precautions were taken, that the gases are liable to injure
vegetation to the extent of 2000 metres (2187 yards) around any active
works; the more watery vapour the air contains, the quicker is the gas
precipitated and carried to the earth. If the action of the vapour is
considerable, the leaves of plants dry and wither; the chlorophyll
becomes modified, and no longer gives the normal spectrum, while a
thickening of the rind of trees has also been noticed. The cereals
suffer much; they increase in stalk, but produce little grain. The
leguminosæ become spotted, and have an air of dryness and want of
vigour; while the potato, among plants utilised for food, appears to
have the strongest resistance. Vines are very sensitive to the gas.
Among trees, the alder seems most sensitive; then come fruit-trees, and
last, the hardy forest-trees--the poplar, the ash, the lime, the elm,
the maple, the birch, and the oak.[92]
[92] Those who desire to study more closely the effect of acids
generally on vegetation may consult the various papers of the alkali
inspectors contained in the Local Government Reports. See also
Schubarth, _Die saueren Gase, welche Schwefelsäure- und Soda-Fabriken
verbreiten_. _Verhandlungen des Vereins zur Beförderung des
Gewerbefleisses in Preussen_, 1857, S. 135. Dingler’s _Journal_, Bd.
145, S. 374-427.
Christel, _Ueber die Einwirkung von Säuren-Dämpfen auf die Vegetation_.
_Arch. f. Pharmacie_, 1871, p. 252.
_Vierteljahrsschrift für gerichtliche Medicin_, 17 Bd. S. 404, 1872.
§73. =Action upon Cloth and Manufactured Articles.=--On black cloth the
acid produces a green stain, which is not moist and shows no corrosion.
On most matters the stain is more or less reddish; after a little time
no free acid may be detected, by simply moistening the spot; but if the
stain is cut out and boiled with water, there may be some evidence of
free acid. The absence of moisture and corrosion distinguishes the stain
from that produced by sulphuric acid.
§74. =Poisonous Effects of Hydrochloric Acid Gas.=--Eulenberg[93] has
studied the effects of the vapour of this acid on rabbits and pigeons.
One of these experiments may be cited in detail. Hydrochloric acid gas,
prepared by heating together common salt and sulphuric acid, was passed
into a glass shade supported on a plate, and a rabbit was placed in the
transparent chamber thus formed. On the entrance of the vapour, there
was immediate blinking of the eyes, rubbing of the paws against the
nostrils, and emission of white fumes with the expired breath, while the
respiration was irregular (40 to the minute). After the lapse of ten
minutes, the gas was again introduced, until the atmosphere was quite
thick; the symptoms were similar to those detailed above, but more
violent; and in fourteen minutes from the commencement, the rabbit sank
down on its right side (respirations 32). When twenty-two minutes had
elapsed, the gas was again allowed to enter. The rabbit now lay quiet,
with closed eyes and laboured respiration, and, finally, after
half-an-hour of intermittent exposure to the gas, the animal was
removed.
[93] _Gewerbe Hygiene_, Berlin, 1876, S. 51.
The cornea were opalescent, and the eyes filled with water; there was
frequent shaking of the head and working of the forepaws. After three
minutes’ exposure to the air, the respirations were found to be 128 per
minute; this quickened respiration lasted for an hour, then gave place
to a shorter and more superficial breathing. On the second day after the
experiment, the rabbit suffered from laboured respiration (28 to the
minute) and pain, and there was a rattling in the bronchial tubes. The
animal died on the third day, death being preceded by slow respiration
(12 to the minute).
The appearances twenty-four hours after death were as follows:--The eyes
were coated with a thick slime, and both cornea were opalescent; there
was strong rigidity of the body. The pia mater covering the brain was
everywhere hyperæmic, and at the hinder border of both hemispheres
appeared a small clot, surrounded by a thin layer of bloody fluid. The
_plex. venos spin._ was filled with coagulated blood, and there was also
a thin extravasation of blood covering the medulla and pons. The lungs
were mottled bright brown-red; the middle lobe of the right lung was
dark brown, solid, and sank in water; the lower lobe of the same lung
and the upper lobe of the left lung were nearly in a similar condition,
but the edges were of a bright red. The parenchyma in the darker places
on section did not crepitate. On the cut surface was a little dark,
fluid, weakly-acid blood; the tracheal mucous membrane was injected. The
heart was filled with thick coagulated blood; the liver was congested,
of a reddish-brown colour, and rich in dark, fluid blood: in the vena
cava inferior was coagulated blood. The kidneys were not hyperæmic; the
intestines were superficially congested.
I think there can be little doubt that the symptoms during life, and the
appearances after death, in this case are perfectly consistent with the
following view:--The vapour acts first as a direct irritant, and is
capable of exciting inflammation in the lung and bronchial tissues; but
besides this, there is a secondary effect, only occurring when the gas
is in sufficient quantity, and the action sufficiently prolonged--viz.,
a direct coagulation of the blood in certain points of the living
vessels of the lungs. The consequence of this is a more or less general
backward engorgement, the right side of the heart becomes distended with
blood, and the ultimate cause of death is partly mechanical. The
hyperæmia of the brain membranes, and even the hæmorrhages, are quite
consistent with this view, and occur in cases where the obstruction to
the circulation is of a coarser and more obvious character, and can
therefore be better appreciated.
§ 75. =Effects of the Liquid Acid.=--There is one distinction between
poisoning by hydrochloric and the other mineral acids--namely, the
absence of corrosion of the skin. Ad. Lesser[94] has established, by
direct experiment, that it is not possible to make any permanent mark on
the skin by the application even of the strongest commercial acid (40
per cent.). Hence, in any case of suspected poisoning by acid, should
there be stains on the lips and face as from an acid, the presumption
will be rather against hydrochloric. The symptoms themselves differ very
little from those produced by sulphuric acid. The pathological
appearances also are not essentially different, but hydrochloric is a
weaker acid, and the extensive disorganisation, solution, and
perforation of the viscera, noticed occasionally with sulphuric acid,
have never been found in hydrochloric acid poisoning. We may quote here
the following case:--
[94] Virchow’s _Archiv f. path. Anat._, Bd. 83, Hft. 2, S. 215, 1881.
A woman, under the influence of great and sudden grief--not unmixed with
passion--drew a bottle from her pocket, and emptied it very quickly. She
immediately uttered a cry, writhed, and vomited a yellow-green fluid.
The abdomen also became enlarged. Milk was given her, but she could not
swallow it, and death took place, in convulsions, two hours after the
drinking of the poison.
The _post-mortem_ appearances were briefly as follows:--Mouth and tongue
free from textural change: much gas in the abdomen, more especially in
the stomach; the membranes of the brain congested; the lungs filled with
blood. The stomach was strongly pressed forward, of a dark brown-red,
and exhibited many irregular blackish spots, varying from two lines to
half an inch in diameter (the spots were drier and harder than the rest
of the stomach); the mucous membrane, internally, was generally
blackened, and changed to a carbonised, shaggy, slimy mass, while the
organ was filled with a blackish homogeneous pulp, which had no odour.
The gullet was also blackened. A considerable quantity of hydrochloric
acid was separated from the stomach.[95]
[95] _Preuss. Med. Vereinszeit. u. Friederichs Blätter f. gerichtl.
Anthropologie_, 1858, Hft. 6, S. 70.
The termination in this instance was unusually rapid. In a case detailed
by Casper,[96] in which a boy drank an unknown quantity of acid, death
took place in seven hours. In Guy’s Hospital museum, the duodenum and
stomach are preserved of a patient who is said to have died in nine and
a half hours from half an ounce of the acid. The same quantity, in a
case related by Taylor, caused death in eighteen hours. From these and
other instances, it may be presumed that death from acute poisoning by
hydrochloric acid will probably take place within twenty-four hours.
From the secondary effects, of course, death may take place at a remote
period, _e.g._, in a case recorded by Dr. Duncan (_Lancet_, April 12,
1890), a man drank about 1 oz. of HCl accidentally, was admitted to
Charing Cross Hospital the same day, and treated with small quantities
of sodium carbonate, and fed by the rectum. On the eighth day he brought
up 34 oz. of blood; in a month he left apparently perfectly well, but
was admitted again in about six weeks, and died of contraction of the
stomach and stricture of the pylorus on the ninety-fourth day.
[96] Case 230.--_Gerichtliche Medicin_, 6th Ed., Berlin, 1876.
§76. =Post-mortem Appearances.=--The pathological appearances are very
similar to those found in the case already detailed; though the skin of
the face may not be eroded in any way by the acid, yet the more delicate
mucous membrane of the mouth, gullet, &c., appears mostly to be changed,
and is usually white or whitish-brown. There is, however, in the museum
of the Royal College of Surgeons the stomach and gullet (No. 2386c.) of
an infant thirteen months old; the infant drank a tea-cupful of strong
hydrochloric acid, and died nine hours after the dose. The pharynx and
the upper end of the gullet is quite normal, the corrosive action
commencing at the lower end, so that, although the acid was
concentrated, not the slightest effect was produced on the delicate
mucous membrane of the throat and upper part of the gullet. The lower
end of the gullet and the whole of the stomach were intensely congested;
the rugæ of the latter were ecchymosed and blackened by the action of
the acid. There were also small hæmorrhages in the lungs, which were
ascribed to the action of the acid on the blood. Perforation of the
stomach has not been noticed in hydrochloric acid poisoning.
In Guy’s Hospital museum (prep. 1799¹⁰), the stomach and duodenum of the
case mentioned exhibit the mucous membrane considerably injected, with
extravasations of blood, which, at the time when the preparation was
first arranged, were of various hues, but are now somewhat altered,
through long keeping in spirit. In St. George’s Hospital museum (ser. x.
43, d. 200) are preserved the stomach and part of the duodenum of a
person who died from hydrochloric acid. The case is detailed in the
_Medical Times and Gazette_ for 1853, vol. ii. p. 513. The whole inner
surface appears to be in a sloughing state, and the larynx and lung were
also inflamed.
A preparation, presented by Mr. Bowman to King’s College Hospital
museum, exhibits the effects of a very large dose of hydrochloric acid.
The gullet has a shrivelled and worm-eaten appearance; the stomach is
injected with black blood, and was filled with an acid, grumous
matter.[97]
[97] A drawing of parts of the gullet and stomach is given in Guy and
Ferrier’s _Forensic Medicine_.
Looking at these and other museum preparations illustrating the effects
of sulphuric and hydrochloric acids, I was unable (in default of the
history of the cases) to distinguish between the two, by the naked eye
appearances, save in those cases in which the disorganisation was so
excessive as to render hydrochloric acid improbable. On the other hand,
the changes produced by nitric acid are so distinctive, that it is
impossible to mistake its action for that of any other acid. The nitric
acid pathological preparations may be picked out at a glance.
Detection and Estimation of Free Hydrochloric Acid.
§ 77. (1) =Detection.=--A large number of colouring reagents have been
proposed as tests for the presence of free mineral acid; among the best
is _methyl-aniline violet_ decolorised by a large amount of hydrochloric
acid; the violet turns to green with a moderate quantity, and to blue
with a small quantity.
=Tropæolin= (00), in the presence of free mineral acid, strikes a
ruby-red to a dark brown-red.
=Congo-red= is used in the form of paper dyed with the material; large
amounts of free hydrochloric acid strike blue-black, small quantities
blue.
=Günzburg’s test= is 2 parts phloroglucin and 1 part vanillin, dissolved
in 100 parts of alcohol. Fine red crystals are precipitated on the
addition of hydrochloric acid. To test the stomach contents for free
hydrochloric acid by means of this reagent, equal parts of the fluid and
the test are evaporated to dryness in the water-bath in a porcelain
dish. If free hydrochloric acid be present, the evaporated residue shows
a red colour; 1 mgrm. of acid can by this test be detected. The reaction
is not interfered with by organic acids, peptones, or albumin.
Jaksch speaks highly of _benzopurpurin_ as a test. Filter-paper is
soaked in a saturated aqueous solution of benzopurpurin 6 B (the variety
1 or 4 B is not so sensitive), and the filter-paper thus prepared
allowed to dry. On testing the contents of the stomach with the reagent,
if there is more than 4 parts per 1000 of hydrochloric acid the paper is
stained intensely blue-black; but if the colour is brown-black, this is
from butyric or lactic acids, or from a mixture of these acids with
hydrochloric acid. If the paper is washed with pure ether, and the
colour was due only to organic acids, the original hue of the paper is
restored; if the colour produced was due to a mixture of mineral and
organic acids, the brown-black colour is weakened; and, lastly, if due
to hydrochloric acid alone, the colour is not altered by washing with
ether. Acid salts have no action, nor is the test interfered with by
large amounts of albumins and peptones.
A. Villiers and M. Favolle[98] have published a sensitive test for
hydrochloric acid. The test consists of a saturated aqueous solution of
colourless aniline, 4 parts; glacial acetic acid, 1 part; 0·1 mgrm. of
hydrochloric acid strikes with this reagent a blue colour, 1 mgrm. a
black colour. The liquid under examination is brought by evaporation, or
by the addition of water, to 10 c.c. and placed in a flask; to this is
added 5 c.c. of a mixture of equal parts of sulphuric acid and water,
then 10 c.c. of a saturated solution of potassic permanganate, and
heated gently, conveying the gases into 3 to 5 c.c. of the reagent
contained in a test-tube immersed in water. If, however, bromine or
iodine (one or both) should be present, the process is modified as
follows:--The hydracids are precipitated by silver nitrate; the
precipitate is washed, transferred to a small flask, and treated with 10
c.c. of water and 1 c.c. of pure ammonia. With this strength of ammonia
the chloride of silver is dissolved easily, the iodide not at all, and
the bromide but slightly. The ammoniacal solution is filtered, boiled,
and treated with SH₂; the excess of SH₂ is expelled by boiling, the
liquid filtered, reduced to 10 c.c. by boiling or evaporation,
sulphuric acid and permanganate added as before, and the gases passed
into the aniline. The process is inapplicable to the detection of
chlorides or hydrochloric acid if cyanides are present, and it is more
adapted for traces of hydrochloric acid than for the quantities likely
to be met with in a toxicological inquiry.
[98] _Comptes Rend._, cxviii.
(2) =Quantitative estimation of Free Hydrochloric Acid.=--The contents
of the stomach are diluted to a known volume, say 250 or 500 c.c. A
fractional portion is taken, say 10 c.c., coloured with litmus or
phenol-phthalein, and a decinormal solution of soda added drop by drop
until the colour changes; this gives total acidity. Another 10 c.c. is
shaken with double its volume of ether three times, the fluid separated
from ether and titrated in the same way; this last titration will give
the acidity due to mineral acids and acid salts;[99] if the only mineral
acid present is hydrochloric acid the results will be near the truth if
reckoned as such, and this method, although not exact for physiological
research, is usually sufficient for the purpose of ascertaining the
amount of hydrochloric acid or other mineral acids in a case of
poisoning. It depends on the fact that ether extracts free organic
acids, such as butyric and lactic acids, but does not extract mineral
acids.
[99] To distinguish between acidity due to free acid and acid salts, or
to acidity due to the combined action of acid salts and free acids, the
method of Leo and Uffelmann is useful. A fractional portion of the
contents of the stomach is triturated with pure calcium carbonate; if
all the acidity is due to free acid, the fluid in a short time becomes
neutral to litmus; if, on the other hand, the acidity is due entirely to
acid salts, the fluid remains acid; or, if due to both acid and acid
salts, there is a proportionate diminution of acidity due to the
decomposition of the lime carbonate by the free acid. A quantitative
method has been devised upon these principles. See Leo, _Diagnostik der
Krankheiten der Verdauungsorgane_, Hirschwald, Berlin, 1890.
The free mineral acid, after extracting the organic acid by ether, can
also be saturated with cinchonine; this hydrochlorate of cinchonine is
extracted by chloroform, evaporated to dryness, and the residue
dissolved in water acidified by nitric acid and precipitated by silver
nitrate; the silver chloride produced is collected on a small filter,
washed, and the filter, with its contents, dried and ignited in a
porcelain crucible; the silver chloride, multiplied by 0·25426, equals
HCl.
The best method of estimating free hydrochloric acid in the stomach is
that of Sjokvist as modified by v. Jaksch;[100] it has the disadvantage
of its accuracy being interfered with by phosphates; it also does not
distinguish between actual free HCl and the loosely bound HCl with
albuminous matters,--this in a toxicological case is of small
importance, because the quantities of HCl found are likely to be large.
[100] _Klinische Diagnostik_, Dr. Rudolph v. Jaksch, Wien u. Leipzig,
1892. _Clinical Diagnosis_. English Translation, by Dr. Cagney. Second
Edition. London: Charles Griffin & Co., Limited.
The method is based upon the fact that if carbonate of baryta be added
to the contents of the stomach, the organic acids will decompose the
barium carbonate, forming butyrate, acetate, lactate, &c., of barium;
and the mineral acids, such as hydrochloric acid, will combine, forming
salts of barium.
On ignition, chloride of barium will be unaffected, while the organic
salts of barium will be converted into carbonate of barium, practically
insoluble in carbonic acid free water.
The contents of the stomach are coloured with litmus, and barium
carbonate added until the fluid is no longer acid (as shown by the
disappearance of the red colour); then the contents are evaporated to
dryness in a platinum dish, and ignited at a dull red heat; complete
burning to an ash is not necessary. After cooling, the burnt mass is
repeatedly exhausted with boiling water and filtered; the chloride of
barium is precipitated from the filtrate by means of dilute sulphuric
acid; the barium sulphate filtered off, washed, dried, and, after
ignition, weighed; 233 parts of barium sulphate equal 73 parts of HCl.
A method somewhat quicker, but depending on the same principles, has
been suggested by Braun.[101] A fractional part, say 10 c.c., of the
fluid contents is coloured by litmus and titrated with decinormal soda.
To the same quantity is added 2 or 3 more c.c. of decinormal soda than
the quantity used in the first titration; this alkaline liquid is
evaporated to dryness and ultimately ignited. To the ash is now added
exactly the quantity of decinormal sulphuric acid as the decinormal soda
last used to make it alkaline--that is to say, if the total acidity was
equal to 3·6 d.n. soda, and 5·0 d.n. soda was added to the 10 c.c.
evaporated to dryness and burned, then 5·6 c.c. of d.n. sulphuric acid
is added to the ash. The solution is now warmed to get rid of carbon
dioxide, and, after addition of a little phenolphthalein, titrated with
d.n. soda solution until the change of colour shows saturation, the
number of c.c. used, multiplied by 0·00365, equals the HCl.
[101] _Op. cit._, S. 157.
§78. In investigating the stains from hydrochloric acid on fabrics, or
the leaves of plants, any free hydrochloric acid may be separated by
boiling with water, and then investigating the aqueous extract. Should,
however, the stain be old, all free acid may have disappeared, and yet
some of the chlorine remain in organic combination with the tissue, or
in combination with bases. Dr. Angus Smith has found weighed portions of
leaves, &c., which had been exposed to the action of hydrochloric acid
fumes, richer in chlorides than similar parts of the plants not thus
exposed.
The most accurate method of investigation for the purpose of separating
chlorine from combination with organic matters is to cut out the
stained portions, weigh them, and burn them up in a combustion-tube,
the front portion of the tube being filled with caustic lime known to be
free from chlorides; a similar experiment must be made with the
unstained portions. In this way a considerable difference may often be
found; and it is not impossible, in some instances, to thus detect,
after the lapse of many years, that certain stains have been produced by
a chlorine-holding substance.
III.--Nitric Acid.
§ 79. =General Properties.=--Nitric acid--commonly known in England as
_aqua fortis_, chemically as _nitric acid_, _hydric nitrate_, or _nitric
monohydrate_--is a mono-hydrate of nitrogen pentoxide (N₂O₅), two
equivalents, or 126 parts, of nitric acid containing 108 of N₂O₅, and 18
of H₂O. Anhydrous nitric acid, or nitrogen pentoxide, can be obtained by
passing, with special precautions, dry chlorine over silver nitrate; the
products are free oxygen and nitrogen pentoxide, according to the
following equation:--
Silver Chlorine. Silver Nitrogen Oxygen.
Nitrate. Chloride. Pentoxide.
Ag₂O,N₂O₅ + 2Cl = 2AgCl + N₂O₅ + O
By surrounding the receiver with a freezing mixture, the acid is
condensed in crystals, which dissolve in water, with emission of much
heat, forming nitric acid. Sometimes the crystals, though kept in sealed
tubes, decompose, and the tube, from the pressure of the liberated
gases, bursts with a dangerous explosion.
Pure nitric acid has a specific gravity of 1·52, and boils at 98°. Dr.
Ure examined the boiling point and other properties of nitric acid very
fully. An acid of 1·5 specific gravity boils at 98·8°; of specific
gravity 1·45, at 115·5°; specific gravity 1·40, at 118·8°; of specific
gravity 1·42, at 122·8°. The acid of specific gravity 1·42 is the
standard acid of the British Pharmacopœia. It can always be obtained by
distilling either strong or moderately weak nitric acid; for, on the one
hand, the acid on distillation gets weaker until the gravity of 1·42 is
reached, or, on the other, it becomes stronger.
There is little doubt that acid of 1·42 gravity is a definite hydrate,
consisting of 1 atom of dry acid and 4 atoms of water; it corresponds to
75 per cent.[102] of the liquid acid HNO₃. There are also at least two
other hydrates known--one an acid of 1·485 specific gravity,
corresponding to 1 atom of dry acid and 2 of water, and an acid of
specific gravity 1·334, corresponding to 1 atom of dry acid and 7 atoms
of water.
[102] The British Pharmacopœia states that the 1·42 acid equals 70 per
cent. of HNO₃; but this is not in accordance with Ure’s Tables, nor with
the facts.