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healthy man, aged thirty-six years, oa 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 hydrocyanio 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. OrAla,-)to show the symptoms it produced. Experiment \st. 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. - t Traite des Poisons, par M. P. Orftla, tout. ii. p. 168.

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, quiokened 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, respiration 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.

Erperiment 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 1hat any antidote against this poison has been successfully employed; vinegar, or the vegetable acids, cofl'ee, a solution of chlorine in water, camphor, emollient drinks, and bleeding, have all been recommended, but their power in counteracting the effeots 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 thfi testimony which is given respecting it. Dr. Granville, in the treatise which we quoted above, gives the following 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 bead, 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 to be, 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.

Evidence may be pushed still farther, and the existence of the prussic acid proved in a most positive manner, by decomposing the precipitate above described, and which is a true prussian .blue, so as to separate the acid. For this purpose, heat the precipitate with an equal quantity of tartaric acid in a glass retort, at the temperature of 150°, when the hydrocyanic vapours will soon exhale from the mixture, and may be received 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 arc to be added.

3. On the addition of sufficient hydrochloric (muriatic) acid to rodissolve 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 oopper 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 hydrocyanic acid; but as the product which is obtained possessesproperties 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 beat.

"There is provided in the central part of the body a hollow muscle, (tho heart) invested with spiral tubes, running in both directions. By the contraction of these fibres, the sides ofthemuscularcavitics 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 \eius which bring it back. This is a general account of the apparatus: and tlie simplest ideaof its 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 ounc6 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 251bs.; so that a quantify 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 ihan the main pipe of the waterworks at London Bridge; and the water roaringin 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 ideafillsthemind 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 p.arts, 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.
Art. IV.

ALCOHOL.

We now come to that part of this complicated process which is, properly speaking, the distiller's art, viz.—the art of extracting the greatest possible quantity of spirit, of the most agreeable flavour, from the fermented liquid, whether that is obtained from ripe fruits, or from the process of malting and fermenting grain. It has been already mentioned, both in the first article on distillation, and in the last, that the alcohol exists ready formed in the wine and in the wash, combined with other substances;

and the art of distillation therefore consists in separating the alcohol from the other substances in the cheapest and best manner. It is an established fact, that alcohol boils at a temperature at least forty degrees below the boiling point of water, and consequently it is volatilized much sooner than any of the other ingredients, except, perhaps, the peculiar volatile oils to which the different spirits owe their flavours, with which it is combined. The object is, to apply this degree of heat, and no more, to the mixture containing the alcohol, so that it may be separated, and nothing carried over with it. In

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genersl, 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, according 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. reclilied 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 einpyrcuma 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; lirst 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 distil 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 otir readers under the various names of brandy, rum, gin, holiands, whisky, arrack, &c, as Ihey are procured from different substances. Brandy is obtained by distilling wine, rum by distilling the fermented juice of the sugar-cane, whisky, gin, and holiands, as well as what is called corn brandy, Khnaptt aqua rikr, &o.:

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