Chapter XX: Part IV: Acids and Alkalies (3)

§ 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.