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healthy man, aged thirty-six years, on being seized as a thief by the police officers, snatched a small sealed phial from his pocket, broke off the neck of it, and swallowed the greatest part of its contents. A strong smell of bitter almonds soon spread around, which almost stupified all present. The culprit staggered a few minutes, then, without a groan, fell on his knees, and sunk lifeless on the ground. Medical assistance being called in, not the slightest trace of pulse or breathing could be found. A few minutes afterwards, a single and violent expiration occurred, which was again repeated in about two minutes. The extremities were perfectly cold, the breast and abdomen still warm, the eyes half open and shining, clear, lively, full, almost projecting, and as brilliant as those of the most ardent youth under violent emotion. The face was neither distorted nor convulsed, but bore the image of quiet sleep. The corpse exhaled a strong smell of bitter almonds, and the remaining liquid being analyzed, was found to be a concentrated solution of prussic acid in alcohol. Several cases are also on record of poisoning by the distilled water of the cherry laurel, the leaves of this plant, and the essential oil of almonds, which we have not room to insert.* All of them, however, show the dreadful effects which substances containing the prussic acid are capable of producing. The modus operandi of hydrocyànic acid appears to be through the medium of the nervous system; and we will here relate one or two of the experiments made with this substance on animals, by M. Orfila,+ to show the symptoms it produced. Experiment 1st. Two drops of prussic acid were given to a young dog; immediately afterwards the respiration was accelerated, its step became unsteady, the animal fell, made water in abundance,

Vide Paris and Fonblanque on Medical Jurisprudence, vol. ii. p. 400.

Traité des Poisons, par M. P. Orfila, tom. ii. p. 168.

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and vomited twice; in a short time it recovered. In five hours' time eight drops more were given to it, when the animal instantly experienced the following symptoms: cough, flow of saliva, quickened respiration, weakness of the hinder extremities, plaintive cries, purging, bending of the body backwards, dilatation of the pupils, rigidity of the muscles, and in less than five minutes, paralysis of the hind feet first, then of the fore feet; general insensibility, excepting of the rump, which was occasionally agitated; accelerated pulse, from 72 to 150 in the minute, great mobility of the eyes and eyelids, and at last complete stupor. Fifteen minutes after this the animal arose, voided its urine, bent the body backwards, and in half an hour was restored. On the following day, sixteen drops of the same poison were again given to this animal. Instantly, quickened respiration, very violent cries, convulsions, opisthotonos (bending of the body forwards), then emprosthotonos (the contrary motion), the ̈ fore feet placed on the head, general tetanus, dilated pupils, ears stiff, urine copious, general paralysis, lapping of the tongue, eyes fixed, eyelids in motion. Five or six minutes afterwards, respira tion difficult, trismus irregular and unexpected movements. At the end of half an hour the animal raised itself, and appeared to suffer in the stomach; was frightened at the least noise, sought the dark, and greatly trembled. One hour after, it ate with a voracious appetite.

Experiment 2d. When thirty or forty drops of prussic acid were administered to dogs or cats, they put forth cries more or less violent, had convulsive motions, and expired six, twelve, or fifteen minutes after taking the poisonous substance.

On examining the bodies of animals or persons poisoned by this acid, no traces of inflammation are to be observed; there is congestion of the veins, whilst the arteries are empty. We are not

aware that any antidote against this poison has been successfully employed; vinegar, or the vegetable acids, coffee, a solution of chlorine in water, camphor, emollient drinks, and bleeding, have all been recommended, but their power in counteracting the effects of this poison has not yet been proved.

The chemical processes by which the presence of hydrocyanic acid may be detected require careful consideration, as in cases where this poison is suspected to have been given with intent to kill, the life of an individual may depend on the nature of the testimony which is given respecting it. Dr. Granville, in the treatise which we quoted above, gives the follow ing directions in conducting the experiments, which should be strictly observed: After collecting the blood contained in the ventricles of the heart, a portion of the contents of the stomach and of the superior intestines, together with a certain quantity of any fluid which may chance to be present within the cavity of the head, chest, or abdomen; and having agitated the mixture for some time in distilled water, and filtered the liquid, taking care to keep the whole at a low temperature, proceed to the following experiments :—

1. To a small quantity of the liquid supposed to contain the acid, add a few drops of a solution of caustic potash in alcohol.

2. To this a few drops of a solution of sulphate of iron must be added, when a cloudy and reddish precipitate, of the colour of burnt terra sienna, will fall down.

3. Some sulphuric acid is now to be introduced into the tube, when the colour of the precipitate will instantly change to that of a bluish green, which, by a permanent contact with the atmosphere, becomes gradually of a beautiful blue, assuming at the same time a pulverulent aspect, if there be any acid present. Or,

1. Treat the filtered liquid with carbonate of potass.

2. Add a solution of sulphate of iron with a small quantity of alum: a precipitate, as in the former method, will fall down, which, if treated by free sulphuric acid, will also become blue and pulverulent. During this latter part of the experiment there is a disengagement of carbonic acid.

farther, and the existence of the Evidence may be pushed still Prussic acid proved in a most pothe precipitate above described, sitive manner, by decomposing and which is a true prussian blue, this purpose, heat the precipitate so as to separate the acid. For with an equal quantity of tartaric acid in a glass retort, at the temperature of 150°, when the hydrofrom the mixture, and may be recyanic vapours will soon exhale ceived in water.

A test by which the presence of a smaller quantity of this acid than can be discovered by the two preceding experiments, has been lately suggested and tried by M. Lassaigne, at Paris. The test made use of consists of the sulphate of copper instead of the sulphate of iron, and the experiment is conducted in the following manner :—

1. Into the liquid supposed to contain the hydrocyanic acid some potash is to be put, so as to slightly alkalize it.

2. To this a few drops of a solution of sulphate of copper are to be added.

3. On the addition of sufficient hydrochloric (muriatic) acid to redissolve the excess of oxide of copper which has been precipitated by the alkali, the liquid instantly assumes a milky appearance, more or less intense, according to the hydrocyanic acid which it contains.

The advantage of the sulphate of copper consists in its detecting much more minute quantities of the acid than the sulphate of iron, and with greater rapidity. We cannot conclude this article without stating that the nitrate of silver will be found a very delicate test for discovering in distilled water

the existence of the hydrocyanie acid; but as the product which is obtained possesses properties which are common to it and the chlorate of silver, with which it may be confounded, the copper is to be preferred.

CIRCULATION OF THE BLOOD. THE following eloquent description of the circulation of the blood, by Dr. Paley, may not be unacceptable to the youthful readers of The Chemist, particularly as its pages have lately contained a dry, but we hope correct account of the process of respiration and animal heat.

“There is provided in the central part of the body a hollow muscle, (the heart) invested with spiral tubes, running in both directions. By the contraction of these fibres, the sides of the muscular cavities are necessarily squeezed together, so as to force out from them any fluid which they may at that time contain: by the relaxation of the same fibres, the cavities are in their turn dilated; and, of course, prepared to admit every fluid which may be poured into them. Into these cavities are inserted the great trunks, both of the arteries which carry out the blood, and of the veins which bring it back. This is a general account of the apparatus: and the simplest idea ofits action is, that by each contraction a portion of blood is forced as by a syringe into the arteries; and at each dilation an equal portion is received from the veins. This produces, at each pulse, a motion and change in the mass of blood to the amount of what the cavity contains, which in a full-grown human heart is about an ounce, or two table-spoons full. Each ventricle will at least contain one ounce of blood. The heart contracts four thousand times in one hour; from which it follows, that there pass through the heart every hour four thousand ounces, or 350lbs. of blood, troy weight. Now the whole mass of blood is about 25lbs.; so that a quantity of

blood equal to the whole blood within the body passes through the heart fourteen times in one hour; which is about once every four minutes. Only consider what this is in very large animals. The aorta of a whale is larger in the bore than the main pipe of the waterworks at London Bridge; and the water roaring in its passage through that pipe is inferior in impetus and velocity to the blood gushing from the whale's heart." According to Dr. Hunter, ten or fifteen gallons of blood are thrown out of the heart of a whale at a stroke, with an immense velocity, through a tube of a foot diameter. The whole idea fills the mind with wonder! See Dr. Hunter's account of the dissection of a whale, in the Philosophical Transactions.

"It was necessary that the blood should be successively brought in contact or proximity with the air; therefore, as soon as the blood is received by the heart from the veins of the body, and before that it is sent out again into its arteries, it is carried by the force of the contraction of the heart, and by means of a supplementary artery, to the lungs; from which, after it has undergone the proper change, it is brought back by a large vein once more to the heart, in order, when thus prepared, to be from thence distributed anew into the system.

"An anatomist, who understood the structure of the heart, might say beforehand that it would play : but he would expect, I think, from the complexity of its mechanism, and the delicacy of many of its parts, that it would always be liable to derangement; or that it would soon work itself out. Yet shall this wonderful machine go, night and day, for eighty years together, at the rate of a hundred thousand strokes every twentyfour hours, having at every stroke a great resistance to overcome; and shall continue this action for this length of time without disorder, and without weariness."Paley's Natural Theology.

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DISTILLATION. no ads and the art of distillation therefore good sive Art. IV.relagayozish consists in separating the alcohol ylotulos ALCOHOL. bioto from the other substances in the We now come to that part of cheapest and best manner. It is this complicated process which is, an established fact, that alcohol properly speaking, the distiller's boils at a temperature at least art, viz. the art of extracting the forty degrees below the boiling greatest possible quantity of spirit, point of water, and consequently it of the most agreeable flavour, from his volatilized much sooner than any the fermented liquid, whether thats of the other ingredients, except, is obtained from ripe fruits, or perhaps, the peculiar volatile oils from the process of malting and to which the different spirits owe fermenting grain. It has been also their flavours, with which it is com ready mentioned, both in the first bined. The object is, to apply article on distillation, and in the this degree of heat, and no more, last, that the alcohol exists ready to the mixture containing the alcoformed in the wine and in the wash, to hol, so that it may be separated, combined with other substances; and nothing carried over with it. In

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general, however, this. principle has not been strictly attended to, and a far greater degree of heat has been applied than is necessary to vaporize the alcohol. Thus, ac-, cording to the mode of distillation at present in use in England, the process has to be repeated. What is first obtained is termed low wines, which, on being again distilled, yield raw spirit, and this gives, by a third distillation, the rectified spirit. All the writers on the subject, and all practical men agree in opinion, that the application of heat should be gradual, and not be increased beyond the degree necessary to separate the alcohol. Two evils, in fact, arise from the employment of too much heat. The first is to separate some empyreuma with the spirit, giving it a harsh, burnt, disagreeable taste, from which it can never be entirely freed; and the second is the greater quantity of time and trouble required to condense the spirit. These principles being admitted, our readers will hear with wonder that the excise laws of England have been so framed as to make it for the interest of the distiller to work

with a greater degree of heat than necessary to separate the alcohol; first compelling him, as already. stated, to make a more concentrated wash than is proper for making a mild, bland, salutary spirit, and then inducing him to disti: that with the greatest possible rapidity, and with as much. heat as he dared to apply. Nay, after the impolicy of these regulations has been shown, after a more economical and better system has been invented, and patents taken out to carry it into effect, the excise regulations, we have been informed, interfere, and absolutely compel the manufacturer to proceed in an unskilful manner, wasting both time and money, and producing a bad commodity.

The liquors resulting from distillation are known to most of our readers under the various names of brandy, rum, gin, hollands, whisky, arrack, &c., as they are procured from different substances. Brandy is obtained by distilling wine, rum by distilling the fermented juice of the sugar-cane, whisky, gin, and hollands, as well as what is called corn brandy, schnaps, aqua vita, &c...

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