CHAPTER VII.

OF THE ALKALIS AND ALKALINE SALTS. The second order of the class of irritants comprehends the alkalis, some of the alkaline salts, and lime. The species which it includes are little allied to one another except in chemical composition; and in particular they are little allied in physiological properties. It appears impossible, however, to make a better arrangement than that proposed by Orfila, which will therefore be here followed. Most of the poisons of the second order are powerful local irritants. Some of them likewise act indirectly on distant organs; and a few are more distinguished by their remote than by their local effects. This order may be conveniently divided into two groups,—the one embracing the two fixed alkalis with their carbonates, nitrates, and chlorides, and also lime,—the other ammonia, with its salts, and likewise the alkaline sulphurets. The action of the first group is purely irritant and strictly local. When concentrated, the fixed alkalis and their carbonates produce chemical decomposition, softening the animal tissues, and reducing them eventually to a pulpy mass; which change depends on their possessing the power, as chemical agents, of dissolving almost all the soft solids of the body. When much diluted, they produce inflammation, without corroding the textures; and it does not appear that they are even then absorbed in such quantity as to prove injurious to any remote organ. The action of the alkaline nitrates and of lime is that of irritants only; at least their chemical action is obscure and feeble. _Of the Fixed Alkalis and their Carbonates._ _Section_ I.—_Of their Tests._ _Potass_ in its caustic state, as usually met with in the shops, forms little gray-coloured cylinders or cakes which have a radiated, crystalline fracture, and an excessively acrid caustic taste, and feel soapy if touched with the wet finger. It deliquesces rapidly in moist air, and then attracts carbonic acid from the atmosphere. It is easily fused by heat, and is exceedingly soluble in water. The solution has a strong alkaline reaction on vegetable colours, restoring reddened litmus to blue, turning syrup of violets or infusion or red cabbage to green, and rendering infusion of turmeric brown. It is distinguished from the alkaline earths when in solution, by not precipitating with carbonic or sulphuric acid, and from soda by the tests to be presently mentioned for its carbonate. _Carbonate of potash_ [subcarbonate, salt of tartar], is usually sold, when pure, in small white grains, formed by melting the salt and stirring it rapidly as it cools. In its impure state it is called in this country potashes, and when somewhat purified, pearl ash. It has then a mixed grayish, yellowish, or bluish colour, and is sold in crumbly lumps of various sizes. In every state it is deliquescent and very caustic. It cannot be crystallized. It gives out carbonic acid gas with the addition of any stronger acid, such as sulphuric, muriatic, or acetic acid. Its solution precipitates yellow with the chloride of platinum, gives a crystalline precipitate with perchloric acid, when the salt forms not less than a fortieth or fiftieth part,—is similarly acted on by a considerable excess of tartaric acid, if the salt constitute about a thirtieth of the fluid,—and yields with the soluble salts of baryta a white precipitate soluble in nitric acid. _Soda_ resembles potass closely in chemical as well as physiological properties; and the _carbonate_ bears the same resemblance to the carbonate of potass. The chief differences are the following. The carbonate of soda is easily crystallized, and effloresces on exposure to the air. A solution in twenty parts of water yields no precipitate with either perchloric acid or an excess of tartaric acid, because there is no sparingly soluble perchlorate or bitartrate, as in the case of potash. Its solution is precipitated by antimoniate of potash, because the antimoniate of soda is very sparingly soluble. All its salts remain unaffected by the chloride of platinum, because their base cannot form like potass an insoluble triple salt with the reagent. The acetate of soda is permanent in the air, while the acetate of potass is one of the most deliquescent salts known. In trying this last test, which is very characteristic, care must be taken to avoid an excess of acid in the acetate of soda by expelling it at a temperature of 212°, otherwise the salt is as deliquescent as the acetate of potass.—Another difference is, that the chloride of sodium, being nearly as soluble in temperate as in boiling water, crystallizes with difficulty and but sparingly by cooling a concentrated boiling solution; while the chloride of potassium is much more soluble in hot than in cold water, and crystallizes easily and abundantly when a concentrated boiling solution is cooled down. _Process for Potash and its Carbonate in Organic Mixtures._—The following method has been lately recommended for the detection of potash and its carbonate in complex organic mixtures. Ascertain that the mixture is alkaline in its action on litmus-paper and turmeric-paper, and that it is not ammoniacal in odour. Distil to one-third; ascertain that it has still an alkaline reaction, and evaporate to dryness in a porcelain basin. Agitate the residue, when cold, with absolute alcohol; boil, pour off the liquor, and filter it while hot. Repeat this with the residuum and more alcohol. Distil off most of the alcohol, and evaporate to dryness. Raise the heat to char the residuum, continue the heat as long as vapours come off, remove the charcoaly matter, and incinerate it for forty-five minutes in a silver crucible. Try to separate potash from what remains by means of absolute alcohol; and if this do not succeed, remove carbonate of potash by boiling water. In either case search for potash by litmus-paper, turmeric-paper, chloride of platinum, and perchloric acid.[429] The conclusiveness of this process depends upon the fact, that absolute alcohol cannot dissolve from solid organic substances such a proportion of lactate, tartrate, acetate, sulphate, or phosphate of potash, or chloride of potassium, as to be acted on by chloride of platinum or perchloric acid.[430]—It is to be observed that carbonate of potash singly is insoluble in absolute alcohol; but it becomes soluble in that fluid, when it is conjoined with various organic matters. Hence it is that this process, intended fundamentally for caustic potash alone, is applicable to carbonate of potash also. _Process for Soda and its Carbonate in Organic Mixtures._—These substances may be separated by the method just described for potash. If the alcoholic solution of the extract of the suspected matter be alkaline in its action on litmus, and be afterwards found to contain soda or its carbonate, the evidence of these substances having been derived from without is satisfactory, because the carbonate of soda contained in many animal matters cannot be so detached. But if no indications of the presence of soda be thus obtained, it is not enough that soda be found in the alcoholic solution of the incinerated alcoholic extract, because the natural carbonate of soda of animal matter may be separated in that manner.[431] SECTION II.—_Of the Action of the fixed Alkalis, and the Symptoms they cause in Man._ The action of the two fixed alkalis and their carbonates on the animal system is so nearly the same, that the facts which have been ascertained in respect to one of them will apply to all the rest. The operation of potass and its carbonate has been carefully investigated by Professor Orfila,[432] and by M. Bretonneau of Tours.[433] When caustic potass is injected in minute portions into the veins, it instantly coagulates the blood. Five grains, according to Orfila, will in this way kill a dog in two minutes. But when small doses either of potash itself, or its carbonate, or indeed any of its salts are used, Mr. Blake found, that without coagulating the blood, they arrested the action of the heart in ten seconds, if injected into the jugular vein; and that when they were injected into the carotid artery, they occasioned in four seconds signs of great obstruction in the capillary circulation, and arrestment of the heart’s action in thirty-five minutes, through means of this effect. Next to the salts of baryta he thought the potash salts the most powerful on the heart’s action of all those he tried.[434] When introduced into the stomach potash acts powerfully as an irritant, and generally corrodes the coats of that organ. Thirty-two grains given by Orfila to a dog caused pain in the gullet, violent vomiting, much anguish, restlessness, and death on the third day. On dissection he found the inner coat of the gullet and stomach black and red; and near the pylorus there was a perforation three-quarters of an inch wide, and surrounded by a hard, elevated margin. The observations of Bretonneau are in some respects different. When potass was swallowed by dogs in the dose of 40 grains, he found that the animals, after suffering for some time from violent vomiting, always died sooner or later of wasting and exhaustion; and that the action of the poison was confined chiefly to the gullet, which was extensively destroyed and ulcerated on its inner surface. But when the gullet was defended by the potass being passed at once into the stomach in a caustic holder, larger doses, even several times repeated, did not prove fatal. The usual violent symptoms of irritation prevailed for two or three days; but on these subsiding, the animals rapidly recovered their appetite and playfulness, appearing in fact to be restored to perfect health. Yet there could be no doubt that the stomach all the while was severely injured; for in some of the animals, which were strangled for the sake of examination several weeks after they took the poison, the villous coat was found extensively removed, and even the muscular and peritonæal coats were here and there destroyed and cicatrized. Bretonneau farther adds, that ten or fifteen grains introduced into the rectum caused death sooner than three times as much given by the mouth. The carbonate of potass possesses properties similar in kind, but inferior in degree to those of the caustic alkali. Two drachms given by Orfila to a dog killed it in twenty-five minutes, violent vomiting and great agony having preceded death. The stomach was universally of a deep-red colour on its inner surface. Potash and its carbonate are absorbed in the course of their action, and may be detected by Orfila’s process in the liver, kidneys, and urine.[435] The actions of soda and its carbonate seem on the whole the same with those of potash; but they are not so energetic. In one respect however soda and its salts differ most materially from those of potash. For while the latter, when admitted directly into a vein, act by arresting the action of the heart, soda and its salts, according to the inquiries of Mr. Blake, have no such effect, but cause death by obstructing the circulation of the pulmonary capillaries, and preventing the return of blood from the lungs to the left side of the heart. This conclusion seems to flow from the following facts. The respiration becomes in a few seconds laborious and soon ceases, whilst the heart continues to beat vigorously: arterial pressure is greatly reduced, while venous pressure is much increased owing to accumulation of blood in the right side of the heart: after death the lungs are found congested and often full of froth: and the heart continues contractile, very turgid in the right side, but quite empty of blood in its left cavities.[436] Poisoning with the caustic alkalis is rare. In 1842, a lady suffering from inflammation of the bowels took an ounce of solution of potass by mistake for kali-water, or a solution of bicarbonate of potash surcharged with carbonic acid. She suffered severely at the time, and died in a fortnight, probably of the conjunct effects of her disease and the poison.[437] This is the only case I have found in print of poisoning with a caustic alkali. But the effects of their carbonates have been several times witnessed, and appear to resemble closely those of the concentrated mineral acids. The symptoms are in the first instance an acrid burning taste, and rapid destruction of the lining membrane of the mouth; then burning and often constriction in the throat and gullet, with difficult and painful deglutition; violent vomiting, often sanguinolent, and tinging vegetable blues green; next acute pain in the stomach and tenderness of the whole belly; subsequently cold sweats, excessive weakness, hiccup, tremors and twitches of the extremities; and ere long violent colic pains, with purging of bloody stools and dark membranous flakes. So far the symptoms are nearly the same in all cases; but in their subsequent course several varieties may be noticed. In the worst form of poisoning death ensues at an early period, for example within twenty-four hours, nay even before time enough has elapsed for diarrhœa to begin. A case of this kind, which has been very well described by Mr. Dewar of Dunfermline, and which arose from the patient, a boy, having accidentally swallowed about three ounces of a strong solution of carbonate of potass, proved fatal in twelve hours only.[438] Here death was owing to the general system or some vital organ being affected through sympathy by the injury sustained by the alimentary canal. In the mildest form, as in a case related by Plenck[439] of a man who swallowed an ounce of the carbonate of potass, the symptoms represent pretty nearly an attack of acute gastritis when followed by recovery,—the effects on man being then analogous to those observed by Bretonneau in animals, when the poison was introduced into the stomach without touching the gullet. But a more common form than either of the preceding is one, similar to the chronic form of poisoning with the mineral acids, in which constant vomiting of food and drink, incessant discharge of fluid, sanguinolent stools, difficulty of swallowing, burning pain from the mouth to the anus, and rapid emaciation, continue for weeks or even months before the patient’s strength is exhausted; and where death is evidently owing to starvation, the alimentary canal being no longer capable of assimilating food. Two characteristic examples of this singular affection have been recorded in the Medical Repository,[440] and a third, of which the event has not been mentioned, but which would in all likelihood end fatally, has been communicated by M. Jules Cloquet to Orfila.[441] Of the two first cases, which were caused by half an ounce of carbonate of potass having been taken in solution by mistake for a laxative salt, one proved fatal in little more than a month, the other three weeks afterwards. In Cloquet’s case, at the end of the sixth week the membrane of the mouth was regenerated; but the gullet continued to discharge pus, and the stools were purulent and bloody. Another form perhaps equally common with that just described, and not less certainly fatal, commences like the rest with violent symptoms of irritation in the mouth, gullet, and stomach; but the bowels are not affected, and by and by it becomes apparent that the stomach is little injured; dysphagia or even complete inability to swallow, burning pain and constriction in the gullet, hawking and coughing of tough, leathery flakes, are then the leading symptoms; at length the case becomes one of stricture of the œsophagus with or without ulceration; the bougie gives only temporary relief, and the patient eventually expires either of mere starvation, or of that combined with an exhausting fever. Mr. Dewar has related a very striking example of this form of poisoning with the alkalis.[442] His patient, after the first violent symptoms had exhausted themselves, which took place in sixteen or eighteen hours, suffered little for four or five days till the sloughs began to separate from the lining membrane of the mouth, throat, and gullet. The affection of the gullet then became gradually predominant, and terminated in stricture, of which she appears to have been several times so much relieved as to have been thought in a fair way of recovery. After repeatedly disappointing Mr. Dewar’s hopes of a successful issue by her intemperance in the use of spirituous liquors, she died of starvation about four months after swallowing the poison. Sir Charles Bell has noticed three parallel cases, and has given delineations of the appearance in the gullet of two of them.[443] One of his patients did not die till twenty years after swallowing the poison, which in this instance was soap-less; yet he does not hesitate to ascribe the stricture to that cause, and says death arose purely from starvation. The carbonate of soda, though a salt in very common use, has not hitherto been the cause of accident, which has found its way into print. It is plainly much less actively corrosive than carbonate of potass, and is therefore probably in every sense less energetic. SECTION III.—_Of the Morbid Appearances caused by the fixed Alkalis._ The morbid appearances caused by potass, soda, and their carbonates differ with the nature of the case. In the boy who died in twelve hours Mr. Dewar found the inner membrane of the throat and gullet almost entirely disorganized and reduced to a pulp, with blood extravasated between it and the muscular coat. The inner coat of the stomach was red, in two round patches destroyed, and the patches covered with a clot of blood;—its outer coat, as well as all the other abdominal viscera, was sound. In the two chronic cases mentioned in the Medical Repository the mischief was much more general, the whole peritonæum being condensed, the omentum dark and turgid, the intestines glued together by lymph, the external coats of the stomach thick, the villous coat almost all destroyed, what remained of it red and near the pylorus ulcerated, and the pyloric orifice of the stomach plugged up with lymph so as barely to admit a small probe. In Mr. Dewar’s patient who died of stricture of the gullet the intestines were sound, the inner surface of the stomach red especially towards the cardia, the inner and muscular coats of the gullet thickened and firmly incorporated together by effused lymph, the inner coat here and there wanting, the passage of the gullet every where contracted, and to such a degree about two inches above the cardia as hardly to pass a common probe. In Sir C. Bell’s cases the appearances were similar. Orfila says he is led to conclude from a great number of facts that of all corrosive poisons potass is the one which most frequently perforates the stomach.[444] This appearance, however, has not been mentioned in any case of poisoning in the human subject. SECTION IV.—_Of the Treatment of Poisoning with the fixed Alkalis._ In the treatment of poisoning with the alkalis the first object is evidently to neutralize the poison. This may be done either with a weak acid, or with oil. Of the acids the acetic in the form of vinegar is most generally recommended, as it is not itself injurious. A successful case in very unpromising circumstances, where two ounces and a half of carbonate of potash had been taken by mistake for cream of tartar, and where the antidote was not administered for half an hour, has been related by M. Liégard of Caen. Great relief was experienced to the burning in the throat and stomach, the chilliness, difficult breathing, and frequent efforts to vomit, which were the first symptoms; and after repeated alternations of collapse and reaction, convalescence was established in eight days.[445]—M. Chereau thinks that for the mineral alkalis and their carbonates fixed oil is a preferable antidote to vinegar; and he has given the heads of two cases of poisoning with large doses of carbonate of potass, in which the free employment of almond oil prevented the usual fatal consequences. It appears to act partly by rendering the vomiting free and easy, partly by converting the alkali into a soap. It must be given in large quantity, several pounds being commonly required.[446] For the subsequent treatment the reader may consult the paper of Mr. Dewar, which contains many useful hints on the management of the most complex description of cases.