corresponding to about 30 per cent. of HNO₃. The dilute nitric acid of
the Pharmacopœia is a colourless liquid, of specific gravity 1·101, and
should contain about 17·4 per cent. of acid. The acids used in various
industries are known respectively as _dyers’_ and _engravers’_ acid.
_Dyers’_ acid has a specific gravity of 1·33 to 1·34 (66° to 68° Twad.),
that is, strength from 56 to 58 per cent. of HNO₃. _Engravers’_ acid is
stronger; being of 1·40 specific gravity (80° Twad.); and contains 70
per cent. of HNO₃. Although the _pure_ acid of commerce is (and should
be) almost colourless, most commercial specimens are of hues from yellow
up to deep red. An acid saturated with red oxides of nitrogen is often
known as “fuming nitric acid.”
§ 80. =Use in the Arts.=--Nitric acid is employed very extensively in
the arts and manufactures. The dyer uses it as a solvent for tin in the
preparation of valuable mordants for calico and other fabrics; the
engraver uses it for etching copper. It is an indispensable agent in the
manufacture of gun-cotton, nitro-glycerin, picric acid, and sulphuric
acid; it is also used in the manufacture of tallow, in preparing the
felt for hats, and in the gilding trades. It is said to be utilised to
make yellowish or fawn-coloured spots on cigar leaves, so as to give
them the appearance of age and quality. It is also used as a medicine.
§ 81. =Statistics of Poisoning by Nitric Acid.=--In the ten years
1883-1892 no case of murder was ascribed to nitric acid, but it caused
accidentally 25 deaths, and was used in 27 cases of suicide.
The following tables give the age and sex distribution of these
deaths:--
DEATHS IN ENGLAND AND WALES DURING THE TEN YEARS ENDING 1892 FROM NITRIC
ACID.
ACCIDENT OR NEGLIGENCE.
Ages, 1-5 5-15 15-25 25-65 65 and Total
above
Males, 6 2 1 9 ... 18
Females, 3 ... ... 4 ... 7
--------------------------------------
Totals, 9 2 1 13 ... 25
--------------------------------------
SUICIDE.
Ages, 15-25 25-65 65 and Total
above
Males, 3 14 1 18
Females, 1 8 ... 9
----------------------------
Totals, 4 22 1 27
----------------------------
§ 82. =Fatal Dose.=--The dose which causes death has not been
ascertained with any exactness. As in the case of sulphuric acid, we may
go so far as to say that it is possible for a few drops of the strong
acid to be fatal, for if brought into contact with the vocal apparatus,
fatal spasm of the glottis might be excited. The smallest dose on record
is 7·7 grms. (2 drachms), which killed a child aged 13.
§ 83. =Action of Nitric Acid on Vegetation.=--Nitric acid acts on plants
injuriously in a two-fold manner--viz., by direct corrosive action, and
also by decomposing the chlorides which all plants contain, thus setting
free chlorine, which decomposes and bleaches the chlorophyll. The action
is most intense on soft and delicate leaves, such as those of clover,
the cabbage, and all the cruciferæ. The tobacco plant is particularly
injured by nitric acid. Next to all herbaceous plants, trees, such as
the apple, pear, and fruit trees, generally suffer. The coniferæ,
whether from their impregnation with resin, or from some other cause,
possess a considerable resisting-power against nitric acid vapours, and
the same is true as regards the cereals; in the latter case, their
siliceous armour acts as a preserving agent.
§ 84. =Nitric Acid Vapour.=--The action of nitric acid in a state of
vapour, as evolved by warming potassic nitrate and sulphuric acid
together, has been studied by Eulenberg. A rabbit was placed under a
shade into which 63 grains of nitric acid in a state of vapour were
introduced. From the conditions of the experiment, some nitric peroxide
must also have been present. Irritation of the external mucous membranes
and embarrassment in breathing were observed. The animal in forty-five
minutes was removed, and suffered afterwards from a croupous bronchitis,
from which, however, it completely recovered in eleven days. A second
experiment with the same animal was followed by death. On inspection,
there was found strong injection of the cerebral membranes, with small
extravasations of blood; the lungs were excessively congested; the right
middle lobe especially was of a liver-brown colour, and empty of air: it
sank in water.
O. Lassar[103] has also made a series of researches on the influence of
nitric acid vapour, from which he concludes that the acid is not
absorbed by the blood, but acts only by its mechanical irritation, for
he could not trace, by means of an examination of the urine, any
evidence of such absorption.
[103] Hoppe-Seyler’s _Zeitschrift f. physiol. Chemie_, Bd. i. S.
165-173, 1877-78.
There are a few instances on record of the vapour having been fatal to
men; for example, the well-known case of Mr. Haywood, a chemist of
Sheffield, may be cited. In pouring a mixture of nitric and sulphuric
acids from a carboy of sixty pounds capacity, the vessel broke, and for
a few minutes he inhaled the mixed fumes. He died eleven hours after
the accident, although for the first three hours there were scarcely any
symptoms of an injurious effect having been produced. On inspection,
there was found intense congestion of the windpipe and bronchial tubes,
with effusion of blood in the latter. The lining membrane of the heart
and aorta was inflamed; unfortunately, the larynx was not examined.[104]
[104] _Lancet_, April 15, 1854, p. 430.
A very similar case happened in Edinburgh in 1863.[105] Two young men
were carrying a jar of nitric acid; the jar broke, and they attempted to
wipe up the acid from the floor. The one died ten hours after the
accident, the other in less than twenty-four hours. The symptoms were
mainly those of difficult breathing, and it is probable that death was
produced from suffocation. Dr. Taylor relates also, that having
accidentally inhaled the vapour in preparing gun-cotton, he suffered
from severe constriction of the throat, tightness in the chest, and
cough, for more than a week.[106]
[105] _Chemical News_, March 14, 1863, p. 132.
[106] _Principles and Practice of Medical Jurisprudence_, vol. i., 1873,
p. 218.
§ 85. =Effects of Liquid Nitric Acid.=--Poisoning by nitric acid, though
still rare, is naturally more frequent than formerly. At the beginning
of this century, Tartra[107] wrote a most excellent monograph on the
subject, and collated all the cases he could find, from the first
recorded instances related by Bembo[108] in Venetian history, down to
his own time. The number of deaths in those 400 years was but
fifty-five, while, in our century, at least fifty can be numbered. Most
of these (74 per cent.) are suicidal, a very few homicidal, the rest
accidental. In one of Tartra’s cases, some nitric acid was placed in the
wine of a drunken woman, with fatal effect. Osenbrüggen[109] relates the
case of a father murdering his six children by means of nitric acid; and
C. A. Büchner[110] that of a soldier who poured acid into the mouth of
his illegitimate infant. A curious case is one in which a man poisoned
his drunken wife by pouring the acid into her right ear; she died after
six weeks’ illness. All these instances prove again, if necessary, that
the acid is only likely to be used with murderous intent in the case of
young children, or of sleeping, drunken, or otherwise helpless people.
[107] Tartra, A. E., Dr., _Traité de l’Empoisonnement par l’Acide
Nitrique_, Paris, An. 10 (1802), pp. 300.
[108] _Bembo Cardinalis, Rerum Venetarium Historiæ_, lib. xii., lib. i.
p. 12, Paris Ed., 1551.
[109] _Allgem.-Deutsche Strafrechtszeitung, herausgeg. v. Frz. v.
Holtzendorff_, 5 Jahrg., 1865, Hft. 5, S. 273.
[110] Friederich’s _Blätter f. ger. Med._, 1866, Hft. 3, S. 187.
As an example of the way in which accidents are brought about by
heedlessness, may be cited the recent case of a woman who bought a small
quantity of aqua fortis for the purpose of allaying toothache by a
local application. She attempted to pour the acid direct from the bottle
into the cavity of the tooth; the acid went down her throat, and the
usual symptoms followed. She threw up a very perfect cast of the gullet
(preserved in University College museum), and rapidly died. Nitric acid
has been mistaken for various liquids, and has also been used by
injection as an abortive, in every respect having a toxicological
history similar to that of sulphuric acid.
§ 86. =Local Action.=--When strong nitric acid comes in contact with
organic matters, there is almost constantly a development of gas. The
tissue is first bleached, and then becomes of a more or less intense
yellow colour. Nitric acid spots on the skin are not removed by ammonia,
but become of an orange-red when moistened with potash and a solution of
cyanide of potassium. The yellow colour seems to show that picric acid
is one of the constant products of the reaction; sulphide of ammonium
forms a sort of soap with the epidermis thus attacked, and detaches it.
§ 87. =Symptoms.=--The symptoms and course of nitric acid poisoning
differ in a few details only from those of sulphuric acid. There is the
same instant pain and frequent vomiting, destruction of the mucous
membranes, and, in the less severe cases, after-contraction of the
gullet, &c.
One of the differences in the action of nitric and sulphuric acids is
the constant development of gas with the former. This, without doubt,
adds to the suffering. Tartra made several experiments on dead bodies,
and showed that very considerable distension of the intestinal canal, by
gaseous products, was the constant result; the tissues were corroded and
almost dissolved, being transformed, ultimately, into a sort of greasy
paste. The vomited matters are of a yellow colour, unless mixed with
blood, when they are of a dirty-brown hue, with shreds of yellow mucus,
and have the strong acid reaction and smell of nitric acid. The teeth
may be partially attacked from the solvent action of the acid on the
enamel. The fauces and tongue, at first blanched, soon acquire a
citron-yellow, or even a brown colour; the whole cavity may swell and
inflame, rendering the swallowing of liquids difficult, painful, and
sometimes impossible. The air passages may also become affected, and in
one case tracheotomy was performed for the relief of the breathing.[111]
The stomach rejects all remedies; there are symptoms of collapse; quick,
weak pulse, frequent shivering, obstinate constipation, and death (often
preceded by a kind of stupor) in from eighteen to twenty-four hours. The
intellectual faculties remain clear, save in a few rare instances.
[111] Arnott, _Med. Gaz._, vol. xii. p. 220.
C. A. Wunderlich has recorded an unusual case, in which the symptoms
were those of dysentery, and the large intestine was found acutely
inflamed, while the small one was little affected. The kidneys had the
same appearance as in Bright’s disease.[112] The smallest fatal dose
given by Taylor is from 2 drachms, which killed a child aged 13 years.
Should the dose of nitric acid be insufficient to kill at once, or, what
amounts to the same thing, should the acid be immediately diluted with
water, or in some way be neutralised, the patient, as in the case of
sulphuric acid, may yet die at a variable future time from stenosis of
the gullet, impaired digestion, &c. For example, in an interesting case
related by Tartra,[113] a woman, who had swallowed 42 grms. (1·5 oz.) of
nitric acid, feeling acute pain, took immediately a quantity of water,
and three hours afterwards was admitted into hospital, where she
received appropriate treatment. At the end of a month she left,
believing herself cured; but in a little while returned, and was
re-admitted, suffering from marasmus, extreme weakness, and constant
vomiting; ultimately she died. The _post-mortem_ examination revealed
extreme contraction of the intestinal canal throughout. The lumen would
hardly admit a penholder. The stomach was no larger than an ordinary
intestine, and adherent to adjacent organs; on its internal surface
there were spots, probably cicatrices; there were also changes in the
gullet, but not so marked. A somewhat similar case is related by the
same author in his thirteenth observation. In the Middlesex Hospital
there is preserved the stomach (No. 1363) of a man who died forty days
after swallowing 2 ozs. of nitric acid diluted in a tumbler of water.
The stomach is contracted, the mucous membrane of the lower part of the
gullet, the lesser curvature, and the pyloric end of the stomach is
extensively corroded, showing ulcerated patches commencing to cicatrize.
[112] _De Actionibus quibusdam Acidi Nitrici Caustico in Corpus Humanum
immissi. Programma Academ._, Lipsiæ, 1857, 4.
[113] _Op. cit._
§ 88. =Post-mortem Appearances.=--The pathological changes in the
tongue, gullet, and stomach can be readily studied from the preparations
in the different museums. The staining by the nitric acid appears
unchanged to the naked eye for many years; hence, most of the nitric
acid preparations are in an excellent state of preservation. A very good
example of the pathological changes is to be found in Nos. 1049 and
1050, University College museum.
No. 1049 presents the tongue, pharynx, and larynx of a man who had
swallowed a tea-cupful of nitric acid. The epithelium of the
œsophagus is for the most part wanting, and hangs in shreds; the
dorsum of the tongue, in front of the circumvallate papillæ, is
excavated, and over its central part superficially ulcerated; in
other places the tongue is encrusted with a thick, loose,
fawn-coloured layer, formed probably of desquamated epithelium. The
whole of the mucous surface is stained of a dirty yellow.
No. 1050 is a preparation showing the tongue, gullet, and stomach of
a person who died from the effects of nitric acid. The tongue in
places is smooth and glazed; in others, slightly depressed and
excavated. On the anterior wall and lower portion of the gullet two
large sloughs exist.
Although perforation of the stomach is not so common with nitric as
with sulphuric acid, such an accident may occur, as shown in a
preparation at Guy’s Hospital, in which there is a perforation at
the cardiac end. All the mucous membrane has disappeared, and the
inner surface is for the most part covered with flocculent shreds.
Three ounces of nitric acid are said to have been swallowed, and the
patient lived seventeen hours. There is the usual staining. There is
also in the Middlesex Hospital (No. 1364) the œsophagus and stomach
of a woman aged 30, who died six hours after swallowing 2 to 3 ozs.
of strong nitric acid. The inner coats of the mucous membrane of the
gullet and stomach are in part converted into opaque yellow and
black eschars, and in part to a shreddy pulpy condition. At the most
depending part of the stomach is a large ragged perforation, with
pulpy margins, which allowed the contents of the stomach to escape
into the peritoneal cavity.
In St. Bartholomew’s museum, there is a very good specimen (No.
1870) of the appearances in the gullet and stomach after poisoning
by nitric acid. The case is detailed in _St. Bartholomew’s Hospital
Reports_, vol. v. p. 247. A male died in fifteen hours after
swallowing 1 oz. of nitric acid. The whole mucous membrane is
wrinkled, or rather ploughed, into longitudinal furrows, the yellow
discoloration stops abruptly, with an irregular border, at the
commencement of the stomach, the epithelial and mucous coats of
which are wanting--its surface being rough and of a brownish-red
colour.
The following preparations are to be found in the museum of the
London Hospital:--A. b. 1. and A. b. 8.--A. b. 1. shows the pharynx,
œsophagus, larynx, and stomach of a young woman, who, after taking
half an ounce of nitric acid, died in eight hours. The staining is
very intense; as an unusual feature, it may be noted that the larynx
is almost as yellow as the œsophagus. The abrasion or solution of
the epithelium on the dorsum of the tongue has dissected out the
circumvallate and fungiform papillæ, so that they project with
unusual distinctness. The lining membrane of the gullet throughout
is divided into minute squares by longitudinal and transverse
furrows. The mucous membrane of the stomach appears wholly
destroyed, and presents a woolly appearance.
A. b. 8. shows a very perfect cast of the œsophagus. The case was
that of a woman, aged 35, who swallowed half an ounce of nitric
acid. The symptoms for the first four days were the usual pain in
the throat and stomach, which might be expected; the bowels were
freely open, and the stools dark and offensive. On the sixth day,
there was constant vomiting with offensive breath; on the ninth, the
appearance of the patient was critical, and she threw up the cast
preserved. She died on the tenth day after the taking of the acid.
The gullet, stomach, trachea, and larynx were found after death much
inflamed.
The following preparations are in St. Thomas’ Hospital:--P. 5.--a
stomach with gullet attached. The stomach is covered with
yellowish-green patches of false membrane and deposit; the gullet
has the usual longitudinal furrows so characteristic of corrosive
fluids.
P. 6. is also from a case of nitric acid poisoning. It shows the
lining membrane of the stomach partly destroyed and shreddy, yet but
little discoloured, the hue being a sort of delicate fawn.
To these may be added a case described and figured by Lesser; to a
baby, a few days old, an unknown quantity of fuming nitric acid was
given; the child made a gurgling, choking sound, and died in a few
minutes. The corpse, nine days after death, showed no signs of
decomposition. The tongue and gums were yellow, the gullet less so,
the stomach still less, and the small intestine had no yellow tint;
the whole of the mouth, gullet, and stomach showed the corrosive
action of the acid. The graduation of tint, Lesser remarks, is what
is not seen when the yellow colour is due to poisoning by chromic
acid or by strong solution of ferric perchloride; in such cases,
wherever the liquid has gone, there is a yellowness.[114]
[114] A. Lesser, _Atlas der gerichtlichen Medicin_, Berlin, 1884, Tafel
i. fig. 2.
§ 89. =Detection and Estimation of Nitric Acid.=--The detection either
of free nitric acid or of its salts is not difficult. Free nitric acid,
after preliminary estimation of the total acidity by decinormal soda,
may be separated by the cinchonine process given at p. 100. On
precipitation by ammonia or soda solution, the nitrate of ammonia or
soda (and, it may be, other similarly combined acids) remain in
solution. If free nitric acid is present in small quantity only, it may
be necessary to evaporate the filtrate from the quinine nearly to
dryness, and to test the concentrated liquid for nitric acid. The
ordinary tests are as follows:--
(1.) Nitrates, treated with mercury or copper and strong sulphuric acid,
develop nitric oxide, recognised by red fumes, if mixed with air or
oxygen.
(2.) A nitrate dissolved in a small quantity of water, with the addition
of a crystal of ferrous sulphate (allowed to partially dissolve), and
then of strong sulphuric acid--poured through a funnel with a long tube
dipping to the bottom of the test-tube, so as to form a layer at the
bottom--strikes a brown colour at the junction of the liquid. When the
test is properly performed, there will be three layers--the uppermost
being the nitrate solution, the middle ferrous sulphate, and the lowest
sulphuric acid; the middle layer becomes of a smoky or black hue if a
nitrate is present. Organic matter interferes much with the reaction.
(3.) Nitrates in solution, treated in the cold with a zinc copper
couple, are decomposed first into nitrites, and then into ammonia. The
nitrites may be detected by a solution of metaphenyldiamine, which
strikes a red colour with an infinitesimal quantity. Hence, a solution
which gives no red colour with metaphenyldiamine, when submitted to the
action of a zinc copper couple, and tested from time to time, cannot
contain nitrites; therefore, no nitrates were originally present.
(4.) Nitrates, on being treated with strong sulphuric acid, and then a
solution of indigo carmine dropped in, decolorise the indigo; this is a
useful test--not conclusive in itself, but readily applied, and if the
cinchonine method of separation has been resorted to, with few sources
of error.
There is a process of separating nitric acid direct from any organic
tissue, which may sometimes be useful:--Place the substance in a strong,
wide-mouthed flask, closed by a caoutchouc cork, and in the flask put a
small, short test-tube, charged with a strong solution of ferrous
chloride in hydrochloric acid. The flask is connected to the mercury
pump (see fig. p. 47), and made perfectly vacuous by raising and
lowering the reservoir. When this is effected, the tube SS′P is adjusted
so as to deliver any gas evolved into a eudiometer, or other
gas-measuring apparatus. By a suitable movement of the flask, the acid
ferrous chloride is allowed to come in contact with the tissue, a gentle
heat applied to the flask, and gases are evolved. These may be carbon
dioxide, nitrogen, and nitric oxide. On the evolution of gas ceasing,
the carbon dioxide is absorbed by passing up under the mercury a little
caustic potash. When absorption is complete, the gas, consisting of
nitrogen and nitric oxide, may be measured. A bubble or two of oxygen is
now passed into the eudiometer; if nitric oxide is present, red fumes at
once develop. On absorbing the excess of oxygen and the nitric peroxide
by alkaline pyrogallate, and measuring the residual gas, it is easy to
calculate how much nitric oxide was originally present, according to the
principles laid down in “Foods,” p. 587.
It is also obvious that, by treating nitric oxide with oxygen, and
absorbing the nitric peroxide present by an alkaline liquid of known
strength and free from nitrates or ammonia, the resulting solution may
be dealt with by a zinc copper couple, and the ammonia developed by the
action of the couple directly estimated by titration by a decinormal
hydrochloric acid, if large in quantity, or by “_nesslerising_,” if
small in quantity. Crum’s method of estimating nitrates (“Foods,” p.
568) in the cases of minute stains on fabrics, &c., with a little
modification, may be occasionally applicable.
IV.--Acetic Acid.
§ 90. In the ten years ending 1893 nine deaths (four males and five
females) occurred in England and Wales from drinking, by mistake or
design, strong acetic acid.
A few cases only have been recorded in medical literature although
there have been many experiments on animals.
The symptoms in the human subject consist of pain, vomiting, and
convulsions.
In animals it causes colic, paralysis of the extremities, bloody
urine, and œdema of the lungs. The lethal dose for plant-eating
animals is about 0·49 gramme per kilo.
There should be no difficulty in recognising acetic acid; the odour
alone is, in most cases, strong and unmistakable. Traces are
detected by distilling, neutralising the distillate by soda,
evaporating to dryness, and treating the residue as follows:--A
portion warmed with alcohol and sulphuric acid gives a smell of
acetic ether. Another portion is heated in a small tube of hard
glass with arsenious acid; if acetic acid is present, or an acetate,
a smell of kakodyl is produced.
V.--Ammonia.
§ 91. Ammonia, (NH₃), is met with either as a vapour or gas, or as a
solution of the pure gas in water.
=Properties.=--Pure ammonia gas is colourless, with a strong,
irritating, pungent odour, forming white fumes of ammonic chloride, if
exposed to hydric chloride vapour, and turning red moist litmus-paper
strongly blue. By intense cold, or by a pressure of 6½ atmospheres at
the ordinary temperature, the gas is readily liquefied; the liquid
ammonia boils at 38°; its observed specific gravity is ·731; it freezes
at -57·1°. Ammonia is readily absorbed by water; at 0° water will take
up 1000 times its own volume, and at ordinary temperatures about 600
times its volume. Alcohol also absorbs about 10 per cent. Ammonia is a
strong base, and forms a number of salts. Ammonia is one of the constant
products of the putrefaction of nitrogenous substances; it exists in the
atmosphere in small proportions, and in everything that contains water.
Indeed, water is the only compound equal to it in its universality of
diffusion. The minute quantities of ammonia thus diffused throughout
nature are probably never in the free state, but combinations of ammonia
with hydric nitrate, carbon dioxide, &c.
§ 92. =Uses.=[115]--A solution of ammonia in water has many applications
in the arts and industries; it is used in medicine, and is an
indispensable laboratory reagent.
[115] Sir B. W. Richardson has shown that ammonia possesses powerful
antiseptic properties.--_Brit. Med. Journal_, 1862.
The officinal caustic preparations of ammonia are--_ammoniæ liquor
fortior_ (_strong solution of ammonia_), which should contain 32·5 per
cent. of ammonia, and have a specific gravity of ·891.
_Liquor ammoniæ_ (_solution of ammonia_), specific gravity ·959, and
containing 10 per cent. of ammonia. There is also a _liniment of
ammonia_, composed of olive oil, 3 parts, and ammonia, 1 part.
_Spiritus Ammoniæ Fœtidus_ (_fœtid spirit of ammonia_).--A solution of
assafœtida in rectified spirit and ammonia solution, 100 parts by
measure, contains 10 of strong solution of ammonia.
Strong solution of ammonia is an important ingredient in the
“_linimentum camphoræ composita_” (_compound liniment of camphor_), the
composition of which is as follows:--camphor, 2·5 parts; oil of
lavender, ·125; strong solution of ammonia, 5·0; and rectified spirit,
15 parts. Its content of strong solution of ammonia is then about 22·6
per cent. (equivalent to 7·3 of NH₃).[116]
[116] There is a common liniment for horses used in stables, and
popularly known as “white oil.” It contains 1 part of ammonia, and 4
parts of olive or rape oil; not unfrequently turpentine is added.
Another veterinary liniment, called “egg oil,” contains ammonia, oil of
origanum, turpentine, and the yelks of eggs.
_The carbonate of ammonia_ is also caustic; it is considered to be a
compound of acid carbonate of ammonium, NH₄HCO₃, with carbamate of
ammonium, NH₄NH₂CO₂. It is in the form of colourless, crystalline
masses; the odour is powerfully ammoniacal; it is strongly alkaline, and
the taste is acrid. It completely volatilises with heat, is soluble in
water, and somewhat soluble in spirit.
The officinal preparation is the “_spiritus ammoniæ aromaticus_,” or
aromatic spirit of ammonia. It is made by distilling in a particular way
ammonic carbonate, 4 ozs.; strong solution of ammonia, 8 ozs.; rectified
spirit, 120 ozs.; water, 60 ozs.; volatile oil of nutmeg, 4½ drms.; and
oil of lemon, 6½ drms. Aromatic spirit of ammonia is a solution in a
weak spirit of neutral carbonate, flavoured with oil of lemon and
nutmeg; the specific gravity should be 0·896.
_Smelling salts_ (_sal volatile_) are composed of carbonate of ammonia.
§ 93. =Statistics.=--Falck has found throughout literature notices of
thirty cases of poisoning by ammonia, or some of its preparations. In
two of these it was used as a poison for the purpose of murder, and in
eight with suicidal intent; the remainder were all accidental. The two
criminal cases were those of children, who both died. Six out of eight
of the suicidal, and twelve of the twenty accidental cases also
terminated fatally.
Ammonia was the cause of 64 deaths (39 male, 25 female) by accident and
of 34 (18 male, 16 female) by suicide, making a total of 98 during the
ten years 1883-1892 in England and Wales. At present it occupies the
seventh place among poisons as a cause of accident, the ninth as a means
of suicide.
§ 94. =Poisoning by Ammonia Vapour.=--Strong ammoniacal vapour is fatal
to both animal and vegetable life. There are, however, but few instances
of poisoning by ammonia vapour; these few cases have been, without
exception, the result of accident. Two cases of death are recorded, due
to an attempt to rouse epileptics from stupor, by an injudicious use of
strong ammonia applied to the nostrils. In another case, when
hydrocyanic acid had been taken, there was the same result. An instance
is also on record of poisonous effects from the breaking of a bottle of
ammonia, and the sudden evolution in this way of an enormous volume of
the caustic gas. Lastly, a man employed in the manufacture of ice, by
means of the liquefaction of ammonia (Carré’s process), breathed the
vapour, and had a narrow escape for his life.
§ 95. =Symptoms.=--The symptoms observed in the last case may well serve
as a type of what may be expected to occur after breathing ammonia
vapour. The man remained from five to ten minutes in the stream of gas;
he then experienced a feeling of anxiety, and a sense of constriction in
the epigastrium, burning in the throat, and giddiness. He vomited. The
pulse was small and frequent, the face pale, the mouth and throat
strongly reddened, with increased secretion. Auscultation and percussion
of the chest elicited nothing abnormal, although during the course of
four days he had from time to time symptoms of suffocation, which were
relieved by emetics. He recovered by the eighth day.[117]
[117] Schmidt’s _Jahrbuch_, 1872, i. S. 30.
In experiments on animals, very similar symptoms are produced. There is
increased secretion of the eyes, nose, and mouth, with redness. The cry
of cats becomes remarkably hoarse, and they generally vomit. Great
difficulty in breathing and tetanic convulsions are present. When the
animal is confined in a small closed chamber, death takes place in about
a quarter of an hour.
_On section_, the bronchial tubes, to the finest ramifications, are
found to be filled with a tenacious mucus, and the air passages, from
the glottis throughout, reddened. The lungs are emphysematous, but have
not always any special colour; the heart contains but little coagulated
blood; the blood has a dark-red colour.
§ 96. The chronic effects of the gas, as shown in workmen engaged in
manufactures in which the fumes of ammonia are frequent, appear to be an
inflammation of the eyes and an affection of the skin. The latter is
thought to be due to the ammonia uniting to form a soap with the oil of
the lubricating skin glands. Some observers have also noticed deafness,
and a peculiar colour of the skin of the nose and forehead, among those
who work in guano manufactories. Its usual action on the body appears to
be a diminution of the healthy oxidation changes, and a general lowering
of bodily strength, with evident anæmia.
§ 97. =Ammonia in Solution.--Action on Plants.=--Solutions of strong
ammonia, or solutions of the carbonate, act injuriously on vegetable
life, while the neutral salts of ammonia are, on the contrary, excellent
manures. A 30 per cent. solution of ammonic carbonate kills most plants
within an hour, and it is indifferent whether the whole plant is watered
with this solution, or whether it is applied only to the leaves. If,
after this watering of the plant with ammonic carbonate water, the
injurious salt is washed out as far as possible by distilled water, or
by a weakly acidulated fluid, then the plant may recover, after having
shed more or less of its leaves. These facts sufficiently explain the
injurious effects noticed when urine is applied direct to plants, for
urine in a very short time becomes essentially a solution of ammonic
carbonate.
§ 98. =Action on Human Beings and Animal Life.=--The violence of the
action of caustic solutions of ammonia almost entirely depends on the
state of concentration.
The local action of the strong solution appears to be mainly the
extraction of water and the saponifying of fat, making a soluble soap.
On delicate tissues it has, therefore, a destructive action; but S.
Samuel[118] has shown that ammonia, when applied to the unbroken
epidermis, does not have the same intense action as potash or soda, nor
does it coagulate albumen. Blood, whether exposed to ammonia gas, or
mixed with solution of ammonia, becomes immediately dark-red; then,
later, through destruction of the blood corpuscles, very dark, even
black; lastly, a dirty brown-red. The oxygen is expelled, the hæmoglobin
destroyed, and the blood corpuscles dissolved.
[118] Virchow’s _Archiv f. path. Anat._, Bd. 51, Hft. 1 u. 2, S. 41,
&c., 1870.
The albumen of the blood is changed to alkali-albuminate, and the blood
itself will not coagulate. A more or less fluid condition of the blood
has always been noticed in the bodies of those poisoned by ammonia.
Blood exposed to ammonia, when viewed by the spectroscope, shows the
spectra of alkaline hæmatin, a weak absorption-band, in the
neighbourhood of D; but if the blood has been acted on for some time by
ammonia, then all absorption-bands vanish. These spectra, however, are
not peculiar to ammonia, the action of caustic potash or soda being
similar. The muscles are excited by ammonia, the functions of the nerves
are destroyed.
When a solution of strong ammonia is swallowed, there are two main
effects--(1) the action of the ammonia itself on the tissues it comes
into contact with, and (2) the effects of the vapour on the
air-passages. There are, therefore, immediate irritation, redness, and
swelling of the tongue and pharynx, a burning pain reaching from the
mouth to the stomach, with vomiting, and, it may be, nervous
symptoms. The saliva is notably increased. In a case reported by
Fonssagrives,[119] no less than 3 litres were expelled in the
twenty-four hours. Often the glands under the jaw and the lymphatics of
the neck are swollen.
[119] _L’Union Médicale_, 1857, No. 13, p. 49, No. 22, p. 90.
Doses of from 5 to 30 grammes of the strong solution of ammonia may kill
as quickly as prussic acid. In a case recorded by Christison,[120] death
occurred in four minutes from a large dose, doubtless partly by
suffocation. As sudden a result is also recorded by Plenk: a man, bitten
by a rabid dog, took a mouthful of spirits of ammonia, and died in four
minutes.
[120] Christison, 167.
If death does not occur rapidly, there may be other symptoms--dependent
not upon its merely local action, but upon its more remote effects.
These mainly consist in an excitation of the brain and spinal cord, and,
later, convulsive movements deepening into loss of consciousness. It has
been noticed that, with great relaxation of the muscular system, the
patients complain of every movement causing pain. With these general
symptoms added to the local injury, death may follow many days after the
swallowing of the fatal dose.
Death may also occur simply from the local injury done to the throat and
larynx, and the patient may linger some time. Thus, in a case quoted by
Taylor,[121] in which none of the poison appears actually to have been
swallowed, the man died nineteen days after taking the poison from
inflammation of the throat and larynx. As with the strong acids, so with
ammonia and the alkalies generally, death may also be caused many weeks
and even months afterwards from the effects of contraction of the
gullet, or from the impaired nutrition consequent upon the destruction,
more or less, of portions of the stomach or intestinal canal.
[121] _Principles of Jurisprudence_, i. p. 235.
§ 99. =Post-mortem Appearances.=--In recent cases there is an intense
redness of the intestinal canal, from the mouth to the stomach, and even
beyond, with here and there destruction of the mucous membrane, and even
perforation. A wax preparation in the museum of University College (No.
2378) shows the effects on the stomach produced by swallowing strong
ammonia; it is ashen-gray in colour, and most of the mucous membrane is,
as it were, dissolved away; the cardiac end is much congested.
The contents of the stomach are usually coloured with blood; the
bronchial tubes and glottis are almost constantly found inflamed--even a
croup-like (or diphtheritic) condition has been seen. Œdema of the
glottis should also be looked for: in one case this alone seems to have
accounted for death. The blood is of a clear-red colour, and fluid. A
smell of ammonia may be present.
If a sufficient time has elapsed for secondary effects to take place,
then there may be other appearances. Thus, in the case of a girl who,
falling into a fainting fit, was treated with a draught of undiluted
spirits of ammonia, and lived four weeks afterwards, the stomach
(preserved in St. George’s Hospital museum, 43 b, ser. ix.) is seen to
be much dilated and covered with cicatrices, and the pylorus is so
contracted as hardly to admit a small bougie. It has also been noticed
that there is generally a fatty degeneration of both the kidneys and
liver.
It need scarcely be observed that, in such cases, no free ammonia will
be found, and the question of the cause of death must necessarily be
wholly medical and pathological.
§ 100. =Separation of Ammonia.=--Ammonia is separated in all cases by
distillation, and if the organic or other liquid is already alkaline,
it is at once placed in a retort and distilled. If neutral or acid, a
little burnt magnesia may be added until the reaction is alkaline. It is
generally laid down that the contents of the stomach in a putrid
condition cannot be examined for ammonia, because ammonia is already
present as a product of decomposition; but even under these
circumstances it is possible to give an opinion whether ammonia _in
excess_ is present. For if, after carefully mixing the whole contents of
the stomach, and then drying a portion and reckoning from that weight
the total nitrogen (considering, for this purpose, the contents to
consist wholly of albumen, which yields about 16 per cent. of
nitrogen)--under these conditions, the contents of the stomach yield
more than 16 per cent. of nitrogen as ammonia reckoned on the dry
substance, it is tolerably certain that ammonia not derived from the
food or the tissues is present.
If, also, there is a sufficient evolution of ammonia to cause white
fumes, when a rod moistened with hydrochloric acid is brought near to
the liquid, this is an effect never noticed with a normal decomposition,
and renders the presence of extrinsic ammonia probable.
An alkaline-reacting distillate, which gives a brown colour with the
“nessler” reagent, and which, when carefully neutralised with sulphuric
acid, on evaporation to dryness by the careful heat of a water-bath,
leaves a crystalline mass that gives a copious precipitate with platinic
chloride, but is hardly at all soluble in absolute alcohol, can be no
other substance than ammonia.
§ 101. =Estimation.=--Ammonia is most quickly estimated by distilling,
receiving the distillate in decinormal acid, and then titrating back. It
may also be estimated as the double chloride of ammonium and platinum
(NH₄Cl)₂PtCl₄. The distillate is exactly neutralised by HCl, evaporated
to near dryness, and an alcoholic solution of platinic chloride added in
sufficient quantity to be always in slight excess, as shown by the
yellow colour of the supernatant fluid. The precipitate is collected,
washed with a little alcohol, dried, and weighed on a tared filter; 100
parts of the salt are equal to 7·6 of NH₃.
VI.--Caustic Potash and Soda.
§ 102. There is so little difference in the local effects produced by
potash and soda respectively, that it will be convenient to treat them
together.
=Potash= (=potassa caustica=).--Hydrate of potassium (KHO), atomic
weight 56, specific gravity 2·1.
=Properties.=--Pure hydrate of potassium is a compact, white solid,
usually met with in the form of sticks. When heated to a temperature a
little under redness, it melts to a nearly colourless liquid; in this
state it is intensely corrosive. It rapidly absorbs moisture from the
air, and moist potash also absorbs with great avidity carbon dioxide; it
is powerfully alkaline, changing red litmus to blue. It is soluble in
half its weight of cold water, great heat being evolved during solution;
it forms two definite hydrates--one, KHO + H₂O; the other, KHO + 2H₂O.
It is sparingly soluble in ether, but is dissolved by alcohol,
wood-spirit, fusel oil, and glycerin.
§ 103. =Pharmaceutical Preparations.=--Potassium hydrate, as well as the
solution of potash, is officinal in all pharmacopœias. The _liquor
potassæ_, or solution of potash, of the British Pharmacopœia, is a
strongly alkaline, caustic liquid, of 1·058 specific gravity, and
containing 5·84 per cent. by weight of KHO. It should, theoretically,
not effervesce, when treated with an acid, but its affinity for CO₂ is
so great that all solutions of potash, which have been in any way
exposed to air, contain a little carbonate. Caustic sticks of potash and
lime used to be officinal in the British Pharmacopœia. Filho’s caustic
is still in commerce, and is made by melting together two parts of
potassium hydrate and one part of lime in an iron ladle or vessel; the
melted mass is now moulded by pouring it into leaden moulds. Vienna
paste is composed of equal weights of potash and lime made into a paste
with rectified spirit or glycerin.
§ 104. =Carbonate of Potash= (K₂CO₃ + 1½H₂O), when pure, is in the form
of small white crystalline grains, alkaline in taste and reaction, and
rapidly deliquescing when exposed to moist air; it gives all the
chemical reactions of potassium oxide, and carbon dioxide. Carbonate of
potash, under the name of _salt of tartar_, or potashes, is sold by
oilmen for cleansing purposes. They supply it either in a fairly pure
state, or as a darkish moist mass containing many impurities.
§ 105. =Bicarbonate of Potash= (KHCO₃) is in the form of large
transparent rhombic prisms, and is not deliquescent. The effervescing
solution of potash (_liquor potassæ effervescens_) consists of 30 grains
of KHCO₃ in a pint of water (3·45 grms. per litre), and as much CO₂ as
the water will take up under a pressure of seven atmospheres.
§ 106. =Caustic Soda--Sodium Hydrate= (NaHO).--This substance is a white
solid, very similar in appearance to potassium hydrate; it absorbs
moisture from the air, and afterwards carbon dioxide, becoming solid
again, for the carbonate is not deliquescent. In this respect, then,
there is a great difference between potash and soda, for the former is
deliquescent both as hydrate and carbonate; a stick of potash in a
semi-liquid state, by exposure to the air, continues liquid, although
saturated with carbon dioxide. Pure sodium hydrate has a specific
gravity of 2·0; it dissolves in water with evolution of heat, and the
solution gives all the reactions of sodium hydrate, and absorbs carbon
dioxide as readily as the corresponding solution of potash. The _liquor
sodæ_ of the B.P. should contain 4·1 per cent. of NaHO.
§ 107. =Sodæ Carbonas--Carbonate of Soda=--(Na₂CO₃10H₂O).--The pure
carbonate of soda for medicinal use is in colourless and transparent
rhombic octahedrons; when exposed to air, the crystals effloresce and
crumble. The _sodæ carbonas exsiccata_, or dried carbonate of soda, is
simply the ordinary carbonate, deprived of its water of crystallisation,
which amounts to 62·93 per cent.
§ 108. =Bicarbonate of Soda= (NaHCO₃) occurs in the form of minute
crystals, or, more commonly, as a white powder. The _liquor sodæ
effervescens_ of the B.P. is a solution of the bicarbonate, 30 grains of
the salt in 20 ozs. of water (3·45 grms. per litre), the water being
charged with as much carbonic acid as it will hold under a pressure of
seven atmospheres. _The bicarbonate of soda lozenges_ (_trochisci sodæ
bicarbonatis_) contain in each lozenge 5 grains (327 mgrms.) of the
bicarbonate. The carbonate of soda sold for household purposes is of two
kinds--the one, “seconds,” of a dirty white colour and somewhat impure;
the other, “best,” is a white mass of much greater purity. _Javelle
water_ (_Eau de Javelle_) is a solution of hypochlorite of soda; its
action is poisonous, more from the caustic alkali than from the
chlorine, and may, therefore, be here included.
§ 109. =Statistics.=--Poisoning by the fixed alkalies is not so frequent
as poisoning by ammonia. Falck has collected, from medical literature,
27 cases, 2 of which were the criminal administering of _Eau de
Javelle_, and 5 were suicidal; 22, or 81·5 per cent., died--in 1 of the
cases after twenty-four hours; in the others, life was prolonged for
days, weeks, or months--in 1 case for twenty-seven months. In the ten
years 1883-1892, in England and Wales, there were 27 deaths from
poisoning by the fixed alkalies; 2 were suicidal (1 from potash, the
other from soda); the remaining 25 were due to accident; of these, 7 (3
males and 4 females) were from caustic soda, and 18 (8 males and 10
females) from caustic potash.
§ 110. =Effects on Animal and Vegetable Life.=--The fixed alkalies
destroy all vegetable life, if applied in strong solution or in
substance, by dehydrating and dissolving the tissues. The effects on
animal tissues are, in part, due also to the affinity of the alkalies
for water. They extract water from the tissues with which they come in
contact, and also attack the albuminous constituents, forming
alkali-albuminate, which swells on the addition of water, and, in a
large quantity, even dissolves. Cartilaginous and horny tissues are also
acted upon, and strong alkalies will dissolve hair, silk, &c. The action
of the alkali is by no means restricted to the part first touched, but
has a remarkable faculty of spreading in all directions.
§ 111. =Local Effects.=--The effects of strong alkali applied to the
epidermis are similar to, but not identical with, those produced by
strong acids. S. Samuel[122] has studied this experimentally on the ear
of the rabbit; a drop of a strong solution of caustic alkali, placed on
the ear of a white rabbit, caused stasis in the arteries and veins, with
first a greenish, then a black colour of the blood; the epidermis was
bleached, the hair loosened, and there quickly followed a greenish
coloration on the back of the ear, opposite to the place of application.
Around the burned spot appeared a circle of anastomising vessels, a
blister rose, and a slough separated in a few days. The whole thickness
of the ear was coloured yellowish-green, and, later, the spot became of
a rusty brown.
[122] Virchow’s _Archiv. f. path. Anat._, Bd. 51, Hft. 1 u. 2, 1870.
§ 112. =Symptoms.=--The symptoms observed when a person has swallowed a
dangerous dose of caustic (fixed) alkali are very similar to those
noticed with ammonia, with the important exception that there is no
respiratory trouble, unless the liquid has come into contact with the
glottis; nor has there been hitherto remarked the rapid death which has
taken place in a few ammonia poisonings, the shortest time hitherto
recorded being three hours, as related by Taylor, in a case in which a
boy had swallowed 3 ozs. of a strong solution of carbonate of potash.
There is instant pain, extending from the mouth to the stomach, and a
persistent and unpleasant taste; if the individual is not a determined
suicide, and the poison (as is mostly the case) has been taken
accidentally, the liquid is immediately ejected as much as possible, and
water, or other liquid at hand, drunk freely. Shock may at once occur,
and the patient die from collapse; but this, even with frightful
destruction of tissue, appears to be rare. Vomiting supervenes; what is
ejected is strongly alkaline, and streaked with blood, and has a soapy,
frothy appearance. There may be diarrhœa, great tenderness of the
abdomen, and quick pulse and fever. With caustic potash, there may be
also noticed its toxic effects (apart from local action) on the heart;
the pulse, in that case, is slow and weak, and loss of consciousness and
convulsions are not uncommon. If the collapse and after-inflammation are
recovered from, then, as in the case of the mineral acids, there is all
the horrid sequence of symptoms pointing to contractions and strictures
of the gullet or pylorus, and the subsequent dyspepsia, difficulty of
swallowing, and not unfrequently actual starvation.
§ 113. =Post-mortem Appearances.=--In cases of recent poisoning, spots
on the cheeks, lips, clothing, &c., giving evidence of the contact of
the alkali, should be looked for; but this evidence, in the case of
persons who have lived a few days, may be wanting. The mucous membrane
of the mouth, throat, gullet, and stomach is generally more or less
white--here and there denuded, and will be found in various stages of
inflammation and erosion, according to the amount taken, and the
concentration of the alkali. Where there is erosion, the base of the
eroded parts is not brown-yellow, but, as a rule, pale red. The gullet
is most affected at its lower part, and it is this part which is mostly
subject to stricture. Thus Böhm[123] found that in 18 cases of
contraction of the gullet, collected by him, 10 of the 18 showed the
contraction at the lower third.
[123] _Centralblatt für die Med. Wiss._, 1874.
The changes which the stomach may present if the patient has lived some
time, are well illustrated by a preparation in St. George’s museum (43
a. 264, ser. ix.). It is the stomach of a woman, aged 44, who had
swallowed a concentrated solution of carbonate of potash. She vomited
immediately after taking it, and lived about two months, during the
latter part of which she had to be nourished by injections. She died
mainly from starvation. The gullet in its lower part is seen to be much
contracted, its lining membrane destroyed, and the muscular coats
exposed. The coats of the stomach are thickened, but what chiefly
arrests the attention is a dense cicatrix at the pylorus, with an
aperture so small as only to admit a probe.
The colour of the stomach is generally bright red, but in that of a
child, preserved in Guy’s Hospital museum (No. 1798²⁴), the mucous
membrane is obliterated, the rugæ destroyed, and a dark-brown stain is a
noticeable feature. The stomach is not, however, necessarily affected.
In a preparation in the same museum (No. 1798²⁰) the mucous membrane of
the stomach of a child who swallowed soap-lees is seen to be almost
healthy, but the gullet is much discoloured. The action on the blood is
to change it into a gelatinous mass; the blood corpuscles are destroyed,
and the whole colour becomes of a dirty blackish-red; the spectroscopic
appearances are identical with those already described (see p. 114).
The question as to the effects of chronic poisoning by the alkalies or
their carbonates may arise. Little or nothing is, however, known of the
action of considerable quantities of alkalies taken daily. In a case
related by Dr. Tunstall,[124] a man for eighteen years had taken daily 2
ozs. of bicarbonate of soda for the purpose of relieving indigestion. He
died suddenly, and the stomach was found extensively diseased; but since
the man, before taking the alkali, had complained of pain, &c., it is
hardly well, from this one case, to draw any conclusion.
[124] _Med. Times_, Nov. 30, 1850, p. 564.
It is important to observe that the contents of the stomach may be acid,
although the death has been produced by caustic alkali. A child, aged 4,
drank from a cup some 14 per cent. soda lye. He vomited frequently, and
died in fifteen hours. The stomach contained 80 c.c. of sour-smelling
turbid fluid, the reaction of which was acid. There were hæmorrhagic
patches in the stomach, and signs of catarrhal inflammation; there was
also a similarly inflamed condition of the duodenum.[125]
[125] Lesser, _Atlas d. gericht. Med._, Tafel ii.
§ 114. =Chemical Analysis.=--The tests for potassium or sodium are too
well known to need more than enumeration. The intense yellow flame
produced when a sodium salt is submitted to a Bunsen flame, and the
bright sodium-line at D when viewed by the spectroscope, is a delicate
test; while potassium gives a dull red band in the red, and a faint but
very distinct line in the violet. Potassium salts are precipitated by
tartaric acid, while sodium salts do not yield this precipitate;
potassium salts also give a precipitate with platinic chloride insoluble
in strong alcohol, while the compound salt with sodium is rapidly
dissolved by alcohol or water. This fact is utilised in the separation
and estimation of the two alkalies.
§ 115. =Estimation of the Fixed Alkalies.=--To detect a fixed alkali in
the contents of the stomach, a convenient process is to proceed by
dialysis, and after twenty-four hours, to concentrate the outer liquid
by boiling, and then, if it is not too much coloured, to titrate
directly with a decinormal sulphuric acid. After exact neutralisation,
the liquid is evaporated to dryness, carbonised, the alkaline salts
lixiviated out with water, the sulphuric acid exactly precipitated by
baric chloride, and then, after separation of the sulphate, the liquid
treated with milk of lime. The filtrate is treated with a current of CO₂
gas, boiled, and any precipitate filtered off; the final filtrate will
contain only alkalies. The liquid may now be evaporated to dryness with
either hydrochloric or sulphuric acids, and the total alkalies weighed
as sulphates or chlorides. Should it be desirable to know exactly the
proportion of potassium to sodium, it is best to convert the alkalies
into chlorides--dry gently, ignite, and weigh; then dissolve in the
least possible quantity of water, and precipitate by platinic chloride,
which should be added so as to be a little in excess, but not much. The
liquid thus treated is evaporated nearly to dryness, and then extracted
with alcohol of 80 per cent., which dissolves out any of the double
chloride of platinum and sodium. Finally, the precipitate is collected
on a tared filter and weighed, after drying at 100°. In this way the
analyst both distinguishes between the salts of sodium and potassium,
and estimates the relative quantities of each. It is hardly necessary to
observe that, if the double chloride is wholly soluble in water or
alcohol, sodium alone is present. This, however, will never occur in
operating on organic tissues and fluids, for both alkalies are
invariably present. A correction must be made when complex organic
fluids are in this way treated for alkalies which may be naturally in
the fluid. Here the analyst will be guided by his preliminary
titration, which gives the total free alkalinity. In cases where the
alkali has been neutralised by acids, of course no free alkali will be
found, but the corresponding salt.
VII.--Neutral Sodium, Potassium, and Ammonium Salts.
§ 116. The neutral salts of the alkalies are poisonous, if
administered in sufficient doses, and the poisonous effect of the
sulphate, chloride, bromide, iodide, tartrate, and citrate appears
to depend on the specific action of the alkali metal, rather than on
the acid, or halogen in combination. According to the researches of
Dr. Ringer and Dr. Harrington Sainsbury,[126] with regard to the
relative toxicity of the three, as shown by their effect on the
heart of a frog--first, the potassium salts were found to exert the
most poisonous action, next come the ammonium, and, lastly, the
sodium salts. The highest estimate would be that sodium salts are
only one-tenth as poisonous as those of ammonium or potassium; the
lowest, that the sodium salts are one-fifth: although the
experiments mainly throw light upon the action of the alkalies on
one organ only, yet the indications obtained probably hold good for
the organism as a whole, and are pretty well borne out by clinical
experience.
[126] _Lancet_, June 24, 1882.
There appear to be four cases on record of poisoning by the above
neutral salts; none of them belong to recent times, but lie between
the years 1837-1856. Hence, the main knowledge which we possess of
the poisonous action of the potassium salts is derived from
experiments on animals.
§ 117. =Sodium Salts.=--Common salt in such enormous quantity as
half a pound to a pound has destroyed human life, but these cases
are so exceptional that the poisonous action of sodium salts is of
scientific rather than practical interest.
§ 118. =Potassium Salts.=--Leaving for future consideration the
nitrate and the chlorate of potassium, potassic sulphate and
tartrate are substances which have destroyed human life.
=Potassic Sulphate= (K₂SO₄) is in the form of colourless rhombic
crystals, of bitter saline taste. It is soluble in 10 parts of
water.
=Hydropotassic Tartrate= (KHC₄H₄O₆), when pure, is in the form of
rhombic crystals, tasting feebly acid. It is soluble in 210 parts of
water at 17°.
§ 119. =Action on the Frog’s Heart.=--Both excitability and
contractility are affected to a powerful degree. There is a
remarkable slowing of the pulsations, irregularity, and, lastly,
cessation of pulsation altogether.
§ 120. =Action on Warm-Blooded Animals.=--If a sufficient quantity
of a solution of a potassic salt is injected into the blood-vessels
of an animal, there is almost immediate death from arrest of the
heart’s action. Smaller doses, subcutaneously applied, produce
slowing of the pulse, dyspnœa, and convulsions, ending in death.
Small doses produce a transitory diminution of the force of arterial
pressure, which quickly passes, and the blood-pressure rises. There
is at first, for a few seconds, increase in the number of
pulsations, but later a remarkable slowing of the pulse. The rise in
the blood-pressure occurs even after section of the spinal cord.
Somewhat larger doses cause rapid lowering of the blood-pressure,
and apparent cessation of the heart’s action; but if the thorax be
then opened, the heart is seen to be contracting regularly, making
some 120-160 rhythmic movements in the minute. If the respiration be
now artificially maintained, and suitable pressure made on the walls
of the chest, so as to empty the heart of blood, the blood-pressure
quickly rises, and natural respiration may follow. An animal which
lay thirty-six minutes apparently dead was in this way brought to
life again (_Böhm_). The action of the salts of potassium on the
blood is the same as that of sodium salts. The blood is coloured a
brighter red, and the form of the corpuscles changed; they become
shrivelled through loss of water. Voluntary muscle loses quickly its
contractility when a solution of potash is injected into its
vessels. Nerves also, when treated with a 1 per cent. solution of
potassic chloride, become inexcitable.
§ 121. =Elimination.=--The potassium salts appear to leave the body
through the kidneys, but are excreted much more slowly than the
corresponding sodium salts. Thus, after injection of 4 grms. of
potassic chloride--in the first sixteen hours ·748 grm. of KCl was
excreted in the urine, and in the following twenty-four hours 2·677
grms.
§ 122. =Nitrate of Potash= (KNO₃).--Pure potassic nitrate
crystallises in large anhydrous hexagonal prisms with dihedral
summits; it does not absorb water, and does not deliquesce. Its
fusing point is about 340°; when melted it forms a transparent
liquid, and loses a little of its oxygen, but this is for the most
part retained by the liquid given off when the salt solidifies. At a
red-heat it evolves oxygen, and is reduced first to nitrite; if the
heat is continued, potassic oxide remains. The specific gravity of
the fused salt is 2·06. It is not very soluble in cold water, 100
parts dissolving only 26 at 15·6°; but boiling water dissolves it
freely, 100 parts dissolving 240 of the salt.
A solution of nitrate of potash, when treated with a zinc couple
(see “Foods,” p. 566), is decomposed, the nitrate being first
reduced to nitrite, as shown by its striking a red colour with
metaphenylene-diamine, and then the nitrite farther decomposing, and
ammonia appearing in the liquid. If the solution is alkalised, and
treated with aluminium foil, hydrogen is evolved, and the same
effect produced. As with all nitrates, potassic nitrate, on being
heated in a test-tube with a little water, some copper filings, and
sulphuric acid, evolves red fumes of nitric peroxide.
§ 123. =Statistics.=--Potassic nitrate, under the popular name of
“_nitre_,” is a very common domestic remedy, and is also largely
used as a medicine for cattle. There appear to be twenty cases of
potassic nitrate poisoning on record--of these, eight were caused by
the salts having been accidentally mistaken for magnesic sulphate,
sodic sulphate, or other purgative salt; two cases were due to a
similar mistake for common salt. In one instance, the nitrate was
used in strong solution as an enema, but most of the cases were due
to the taking of too large an internal dose.
§ 124. =Uses in the Arts=, &c.--Both sodic and potassic nitrates are
called “nitre” by the public indiscriminately. Sodic nitrate is
imported in large quantities from the rainless districts of Peru as
a manure. Potassic nitrate is much used in the manufacture of
gunpowder, in the preservation of animal substances, in the
manufacture of gun cotton, of sulphuric and nitric acids, &c. The
maximum medicinal dose of potassium nitrate is usually stated to be
30 grains (1·9 grm.).
§ 125. =Action of Nitrates of Sodium and Potassium.=--Both of these
salts are poisonous. Potassic nitrate has been taken with fatal
result by man; the poisonous nature of sodic nitrate is established
by experiments on animals. The action of the nitrates of the
alkalies is separated from that of the other neutral salts of
potassium, &c., because in this case the toxic action of the
combined nitric acid plays no insignificant part. Large doses, 3-5
grms. (46·3-77·2 grains), of potassic nitrate cause considerable
uneasiness in the stomach and bowels; the digestion is disturbed;
there may be vomiting and diarrhœa, and there is generally present a
desire to urinate frequently. Still larger doses, 15-30 grms.
(231·5-463 grains), rapidly produce all the symptoms of acute
gastro-enteritis--great pain, frequent vomiting (the ejected matters
being often bloody), with irregularity and slowing of the pulse;
weakness, cold sweats, painful cramps in single muscles (especially
in the calves of the legs); and, later, convulsions, aphonia, quick
collapse, and death.
In the case of a pregnant woman, a handful of “nitre” taken in
mistake for Glauber’s salts produced abortion after half-an-hour.
The woman recovered. Sodic nitrate subcutaneously applied to frogs
kills them, in doses of ·026 grm. (·4 grain), in about two hours;
there are fibrillar twitchings of single groups of muscles and
narcosis. The heart dies last, but after ceasing to beat may, by a
stimulus, be made again to contract. Rabbits, poisoned similarly by
sodic nitrate, exhibit also narcotic symptoms; they lose
consciousness, lie upon their side, and respond only to the sharpest
stimuli. The breathing, as well as the heart, is “slowed,” and death
follows after a few spasmodic inspirations.
=Sodic nitrite= was found by Barth to be a more powerful poison,
less than 6 mgrms. (·1 grain) being sufficient to kill a rabbit of
455·5 grms. (7028 grains) weight, when subcutaneously injected. The
symptoms were very similar to those produced by the nitrate.
§ 126. The _post-mortem_ appearances from potassic nitrate are as
follows:--An inflamed condition of the stomach, with the mucous
membrane dark in colour, and readily tearing; the contents of the
stomach are often mixed with blood. In a case related by Orfila,
there was even a small perforation by a large dose of potassic
nitrate, and a remarkable preservation of the body was noted.
It is believed that the action of the nitrates is to be partly
explained by a reduction to nitrites, circulating in the blood as
such. To detect nitrites in the blood, the best method is to place
the blood in a dialyser, the outer liquid being alcohol. The
alcoholic solution may be evaporated to dryness, extracted with
water, and then tested by metaphenylene-diamine.
§ 127. =Potassic Chlorate= (KClO₃).--Potassic chlorate is in the
form of colourless, tabular crystals with four or six sides. About 6
parts of the salt are dissolved by 100 of water at 15°, the
solubility increasing with the temperature, so that at 100° nearly
60 parts dissolve; if strong sulphuric acid be dropped on the
crystals, peroxide of chlorine is evolved; when rubbed with sulphur
in a mortar, potassic chlorate detonates. When the salt is heated
strongly, it first melts, and then decomposes, yielding oxygen gas,
and is transformed into the perchlorate. If the heat is continued,
this also is decomposed, and the final result is potassic chloride.
§ 128. =Uses.=--Potassic chlorate is largely used as an oxidiser in
calico printing, and in dyeing, especially in the preparation of
aniline black. A considerable quantity is consumed in the
manufacture of lucifer matches and fireworks; it is also a
convenient source of oxygen. Detonators for exploding dynamite are
mixtures of fulminate of mercury and potassic chlorate. It is
employed as a medicine both as an application to inflamed mucous
membranes, and for internal administration; about 2000 tons of the
salt for these various purposes are manufactured yearly in the
United Kingdom.
§ 129. =Poisonous Properties.=--The facility with which potassic
chlorate parts with its oxygen by the aid of heat, led to its very
extensive employment in medicine. No drug, indeed, has been given
more recklessly, or on a less scientific basis. Wherever there were
sloughing wounds, low fevers, and malignant sore throats, especially
those of a diphtheritic character, the practitioner administered
potassic chlorate in colossal doses. If the patient died, it was
ascribed to the malignity of the disease--if he recovered, to the
oxygen of the salt; and it is possible, from the light which of
recent years has been thrown on the action of potassic chlorate,
that its too reckless use has led to many unrecorded accidents.
§ 130. =Experiments on Animals.=--F. Marchand[127] has studied the
effects of potassic chlorate on animals, and on blood. If either
potassic chlorate or sodic chlorate is mixed with fresh blood, it
shows after a little while peculiar changes; the clear red colour at
first produced passes, within a few hours, into a dark red-brown,
which gradually becomes pure brown. This change is produced by a 1
per cent. solution, in from fifteen to sixteen hours; and a 4 per
cent. solution at 15° destroys every trace of oxyhæmoglobin within
four hours. Soon the blood takes a syrupy consistence, and, with a
2-4 per cent. solution of the salt, passes into a jelly-like mass.
The jelly has much permanence, and resists putrefactive changes for
a long time.
[127] _Virchow’s Archiv. f. path. Anat._, Bd. 77, Hft. 3, S. 455, 1879.
Marchand fed a dog of 17 kilos. in weight with 5 grms. of potassic
chlorate for a week. As there were no apparent symptoms, the dose
was doubled for two days; and as there was still no visible effect,
lastly, 50 grms. of sodic chlorate were given in 5 doses. In the
following night the dog died. The blood was found after death to be
of a sepia-brown colour, and remained unaltered when exposed to the
air. The organs were generally of an unnatural brown colour; the
spleen was enormously enlarged; the kidneys were swollen, and of a
dark chocolate brown--on section, almost black-brown, the colour
being nearly equal, both in the substance and in the capsule. A
microscopical examination of the kidney showed the canaliculi to be
filled with brownish cylinders consisting of altered blood. A
spectroscopic examination of the blood showed weak hæmoglobin bands,
and a narrow band in the red. With farther dilution, the hæmoglobin
bands vanished, but the band in the red remained. The diluted blood,
when exposed to the light, still remained of a coffee-brown colour;
and on shaking, a white-brown froth was produced on the surface.
A second experiment in which a hound of from 7-8 kilos. in weight
was given 3-5 grm. doses of potassic chlorate in sixteen hours, and
killed by bleeding seven to eight hours after the last dose, showed
very similar appearances. The kidneys were intensely congested, and
the peculiar brown colour was noticeable.
§ 131. =Effects on Man.=--I find in literature thirty-nine cases
recorded, in which poisonous symptoms were directly ascribed to the
action of chlorate of potassium; twenty-eight of these terminated
fatally. A quadruple instance of poisoning, recorded by Brouardel
and L’Hôte,[128] illustrates many of the points relative to the time
at which the symptoms may be expected to commence, and the general
aspect of potassic chlorate poisoning. The “_supérieure_” of a
religious institution was in the habit of giving, for charitable
purposes, a potion containing 15 grms. (3·8 drms.) of potassic
chlorate, dissolved in 360 c.c. (about 12½ ozs.) of a vegetable
infusion.
[128] _Annales d’Hygiène publique_, 1881, p. 232.
This potion was administered to four children--viz., David, aged 2½;
Cousin, aged 3½; Salmont, 2½; and Guérin, 2½. David took the whole
in two and a half hours, the symptoms commenced after the potion was
finished, and the child died five and a half hours after taking the
first dose; there were vomiting and diarrhœa. Cousin took the
medicine in seven hours; the symptoms also commenced after the last
spoonful, and the death took place eight and a half hours from the
first spoonful. The symptoms were mainly those of great depression;
the lips were blue, the pulse feeble, there was no vomiting, no
diarrhœa. Salmont took the medicine in nine hours, and died in
twelve. There was some diarrhœa, the stools were of a green colour.
Guérin took the whole in two hours, the symptoms commenced in four
hours; the lips were very pale, the gums blue. Death took place in
four days.
There was an autopsy in the case of David only. The stomach showed a
large ecchymosis on its mucous membrane, as if it had been burnt by
an acid; the spleen was gorged with blood, and its tissue friable;
the kidneys do not seem to have been thoroughly examined, but are
said to have been tumefied. Potassic chlorate was discovered by
dialysis. In the cases of the children just detailed, the symptoms
appear to be a mixture of the depressing action of the potassium,
and irritant action of the chlorate.
§ 132. In adults, the main symptoms are those of nephritis, and the
fatal dose for an adult is somewhere about an ounce (28·3 grms.),
but half this quantity would probably be dangerous, especially if
given to a person who had congestion or disease of the kidneys.
Dr. Jacobi[129] gives the following cases.
[129] _Amer. Med. Times_, 1860.
Dr. Fountain in 1858, experimenting on himself, took 29·2 grms. (8·7
drms.) of potassic chlorate; he died on the seventh day from
nephritis. A young lady swallowed 30 grms. (8·5 drms.), when using
it as a gargle; she died in a few days from nephritis. A man, thirty
years of age, died in four days after having taken 48 grms. (12·3
drms.) of sodic chlorate in six hours. The _shortest time_ in which
I can find the salt to have been fatal, is a case related by Dr.
Manouvriez, in which a woman took 45 grms., and died in five hours.
The _smallest dose_ which has proved fatal is one in which an infant
three years old was killed by 3 grms. (46·3 grains).
Jacobi considers that the maximum dose to be given in divided doses
during the twenty-four hours, to infants under three, should be from
1-1·5 grm. (15·4-23·1 grains), to children from three years old, up
to 2 grms. (30·8 grains); and adults from 6-8 grms. (92·6-123·4
grains).
§ 133. =Elimination.=--Potassic chlorate is quickly absorbed by
mucous membranes, and by the inflamed skin, and rapidly separated
from the body by the action of the kidneys. Wöhler, as early as
1824, recognised that it in great part passed out of the body
unchanged, and, lately, Isambert, in conjunction with Hirne,[130]
making quantitative estimations, recovered from the urine no less
than 95 per cent. of the ingested salts. Otto Hehner has also made
several auto-experiments, and taking 2½ drms., found that it could
be detected in the urine an hour and a half afterwards. At that time
17·23 per cent. of the salt had been excreted, and, by the end of
eleven hours, 93·8 per cent. was recovered. It is then difficult to
believe that the salt gives any oxygen to the tissues, for though it
is true that in all the investigations a small percentage remains to
be accounted for, and also that Binz,[131] making experiments by
mixing solutions of potassic chlorate with moist organic substances,
such as pus, yeast, fibrin, &c., has declared that, at a blood heat
the chlorate is rapidly reduced, and is no longer recognisable as
chlorate--yet it may be affirmed that potassic chlorate is recovered
from the urine as completely as anything which is ever excreted by
the body, and that deductions drawn from the changes undergone by
the salt in solutions of fibrin, &c., have only an indirect bearing
on the question.
[130] _Gaz. Méd. de Paris_, 1875, Nro. 17, 35, 41, 43.
[131] _Berlin klin. Wochenschr._, xi. 10, S. 119, 1874.
§ 134. The essential action of potassic chlorate seems to be that it
causes a peculiar change in the blood, acting on the colouring
matter and corpuscles; the latter lose their property as oxygen
carriers; the hæmoglobin is in part destroyed; the corpuscles
dissolved. The decomposed and altered blood-corpuscles are crowded
into the kidneys, spleen, &c.; they block up the uriniferous
canaliculi, and thus the organs present the curious colouring seen
after death, and the kidneys become inflamed.
Detection and Estimation of Potassic Chlorate.
§ 135. Organic fluids are best submitted to dialysis; the dialysed
fluid should then be concentrated and qualitative tests applied. One
of the best tests for the presence of a chlorate is, without doubt,
that recommended by Fresenius. The fluid to be tested is acidulated
with a few drops of sulphuric acid; sulphate of indigo added
sufficient to colour the solution blue, and finally a few drops of
sulphurous acid. In presence of potassic or sodic chlorate, the blue
colour immediately vanishes. This method is capable of detecting 1
part in 128,000; provided the solution is not originally coloured,
and but little organic matter is present.
The urine can be examined direct, but if it contain albumen, the
blue colour may disappear and yet chlorate be present; if too much
sulphurous acid be also added, the test may give erroneous results.
These are but trivial objections, however, for if the analyst
obtains a response to the test, he will naturally confirm or
disprove it by the following process:--
The liquid under examination, organic or otherwise, is divided into
two equal parts. In the one, all the chlorine present is
precipitated as chloride by silver nitrate in the usual way, and the
chloride of silver collected and weighed. In the other, the liquid
is evaporated to dryness and well charred by a dull red heat, the
ash dissolved in weak nitric acid, and the chlorides estimated as in
the first case. If chlorates were present, there will be a
difference between the two estimations, proportionate to the amount
of chlorates which have been converted into chlorides by the
carbonisation, and the first silver chloride subtracted from the
second will give an argentic chloride which is to be referred to
chlorate. In this way also the amount present may be quantitatively
estimated, 100 parts of silver chloride equalling 85·4 of potassic
chlorate.
Toxicological Detection of Alkali Salts.
(See also _ante_, p. 121.)
§ 136. Sodium, in combination, especially with chlorine, and also
with sulphuric, carbonic, and phosphoric acids, is found in the
plasma of the blood, in the urinary secretion, in the pancreatic
juice, in human bile, and in serous transudations, &c. Potassium, in
combination, is especially found in the red blood-corpuscles, in the
muscles, in the nervous tissues, and in milk. Ammonia, in
combination with acids, is naturally found in the stomach, in the
contents of the intestine; it is also a natural constituent of the
blood in small traces, and in a corpse is copiously evolved from
putrefactive changes.
It hence follows, that mere qualitative tests for these elements in
the tissues or fluids of the body are of not the slightest use, for
they are always present during the life of the healthiest
individual, and can be found after death in persons dying from any
malady whatever. To establish the fact of a person having taken an
unusual dose of any of the alkali salts, by simply chemical
evidence, it must be proved that the alkalies are present in unusual
quantities or in an abnormal state of combination.
In cases of rapid death, caused by sodic or potassic salts, they
will be found in such quantity in the contents of the stomach, or in
matters vomited, that there will probably be no difficulty in coming
to a direct conclusion; but if some time has elapsed, the analyst
may not find a sufficient ground for giving a decided judgment, the
excretion of the alkali salts being very rapid.
In most cases, it will be well to proceed as follows:--The contents
of the stomach are, if necessary, diluted with distilled water, and
divided into three parts, one of which is submitted to dialysis, and
then the dialysed liquid evaporated to a small bulk and examined
qualitatively, in order to ascertain whether a large amount of the
alkaline salts is present, and in what form. In this way, the
presence or absence of nitrate of potassium or sodium may be proved,
or the iodide, bromide, sulphate, and chlorate detected.
To find, in this way, nitrate of potassium, a coarse test is
preferable to the finer tests dependent upon conversion of the
nitrate into nitrites or into ammonia, for these tests are so
delicate, that nitrates may be detected in traces; whereas, in this
examination, to find traces is of no value. Hence, the old-fashioned
test of treating the concentrated liquid in a test-tube with copper
filings and then with sulphuric acid, and looking for the red fumes,
is best, and will act very well, even should, as is commonly the
case, some organic matters have passed through the dialyser.
Chlorates are indicated if the liquid is divided into two parts and
tested in the manner recommended at p. 127. If present in any
quantity, chlorates or nitrates may be indicated by the brilliant
combustion of the organic matter when heated to redness, as also by
the action of strong sulphuric acid on the solid substances--in the
one case, yellow vapours of peroxide of chlorine being evolved--in
the other, the red fumes already mentioned of nitric peroxide.
With regard to a substance such as the hydro-potassic tartrate, its
insolubility in water renders it not easy of detection by dialysis;
but its very insolubility will aid the analyst, for the contents of
the stomach may be treated with water, and thus all soluble salts of
the alkalies extracted. On now microscopically examining the
insoluble residue, crystals of bitartrate, if present, will be
readily seen. They may be picked up on a clean platinum wire and
heated to redness in a Bunsen flame, and spectroscopically examined.
After heating, the melted mass will have an alkaline reaction, and
give a precipitate with platinic chloride. All other organic salts
of potassium are soluble, and a white crystal giving such reaction
must be hydro-potassic tartrate.
=Ammonium Salts.=--If the body is fresh, and yet the salts of
ammonium present in large amount, it is safe to conclude that they
have an external origin; but there might be some considerable
difficulty in criminal poisoning by a neutral salt of ammonium, and
search for it in a highly putrid corpse. Probably, in such an
exceptional case, there would be other evidence. With regard to the
quantitative separation and estimation of the fixed alkalies in the
ash of organic substances, the reader is referred to the processes
given in “Foods,” p. 99, _et seq._, and in the present work, p. 121.