stomach of a middle-sized rabbit. The animal was much agitated, as usual in such experiments. The pupils became dilated, and the iris immoveable. Motion and sensation were so rapidly destroyed that in five minutes the animal fell down, and showed no action when mechanically irritated. It lay like a body before the setting in of cadaveric rigidity; the globe of the eye alone showing some sensibility. It lay in this state for an hour, with quick breathing, and rapid, rather strong action of the heart. These gradually became slower, and the animal died in an hour and forty minutes. No morbid appearances of any importance were found.

A similar experiment was made on another rabbit with one drachm of the oil. The animal looked dull in five minutes. In ten minutes the irritability of the hinder legs was almost extinct, that of the fore legs less so. The heart's action and breathing were accelerated. The animal in fifteen minutes fell motionless on its side, and remained so for four hours, when it died. There were no important morbid appearances.

In a third experiment, a scruple of the oil was given to a rabbit, but beyond having its breathing quickened it was not injured.

Mitscherlich's conclusions are, that the oil, free from hydrocyanic acid, is a strong poison, weaker than oil of mustard, but stronger than the oils of savin, cinnamon, carraway, nutmeg, fennel, turpentine, lemons, juniper, and copaiba,-that the phenomena preceding death in poisoning by it are rapid exhaustion of voluntary motion and sensation, whilst the heart's action and respiration continue,--that the oil when not free from prussic acid acts in virtue of the presence of the latter, since a scruple of pure oil may be given without fatal effects,-that in large doses it is poisonous, like other volatile oils.

I submit that the detailed account of Mitscherlich's experiments does not warrant the unqualified statement of the editors of Dr Pereira's posthumous volume. In this state of uncertainty, therefore, it appeared to me right to make some experiments to satisfy myself and others as to the real state of the case. My experiments were made on dogs as well as rabbits. For ascertaining the modus operandi of a substance of known poisonous qualities, rabbits answer well, from their not being liable to eject the poison by vomiting; but for determining whether or not a substance may prove fatal to human beings, dogs, as more resembling man in organization and habits, are much to be preferred. The condition of the stomach as regards repletion can be easily regulated in dogs by keeping them from food; but in rabbits uniformity in this respect can never be attained, for even when they have been kept from food for days, masses of undigested vegetable matter will be found in the stomach.

In all the following experiments the oil was administered by injecting it mixed with a little water into the stomach through an elastic tube. The following trials were made upon dogs :

The experiments were made at the Veterinary College; and I have to express my thanks to Mr Dun, lecturer on Materia Medica there, for his valuable assistance.

EXP. I. To a small terrier weighing ten pounds were given twenty-five minims of oil rectified from a mixure of caustic potash and quicklime. This oil, by the iron test, was perfectly free from prussic acid. No visible effect of one kind or another was produced in half an hour. The dog then ate some meat, and continued quite

well.

EXP. II. Two drachms of another sample of rectified oil were given to the same dog seven hours afterwards. In twelve minutes he vomited a little slimy matter smelling of the oil; but he was not in the least distressed. In thirty-five minutes he was quite well, and three and a half hours afterwards, fed heartily.

EXP. III.-One drachm of the same oil used in Exp. II. was given to another dog weighing eleven pounds. It had produced no effect in half an hour. He then became quite lively, having recovered from the usual agitation of the experiment, and remained quite well for a period of several hours, during which he was under observation. Later in the day he had vomited a little, but in the evening was quite well, and ate greedily.

The oil used in these two last experiments had been redistilled from potash and lime, and was reported pure by the gentleman who prepared it; but on applying the iron test to half a drachm of it, I got from it a very decided precipitate of prussian blue.

These experiments show that in doses of one or two drachms, oil which has been rectified, but in which some hydrocyanic acid may still be detected, is not poisonous to dogs. Instead, however, of applying to them this somewhat hazardous signification, I would rather have them interpreted as showing that the iron test, as applied to the oil, is of sufficient delicacy to detect traces of prussic acid so small as not to be poisonous.

EXP. IV. To a dog, weighing sixteen pounds, three drachms of this same oil were given. No effect was produced for twenty-five minutes, when he vomited once. No other symptom showed itself, and the animal was quite well next day.

EXP. V. To the same dog, as in Nos. I. and II., three drachms of another sample of rectified oil were administered. This oil, with the iron test, gave so infinitesimal a trace of prussian blue, that it may be said to have been free from hydrocyanic acid. The dog vomited slightly in thirteen minutes, and, in about three minutes more, passed some urine smelling distinctly of the oil. No further symptoms were produced in half an hour. Shortly after that he vomited once again, but otherwise remained quite well.

The exemption from the action of poison in these trials cannot be ascribed to the expulsion of the oil by vomiting; for in one it did

NEW SERIES.-NO. XLIX. JANUARY 1854.

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not occur for 25 minutes, and in the other not until a quantity of the oil had been absorbed into the circulation.

EXP. VI. was made, to contrast with these trials, the effects of the unrectified oil. Half a drachm of ordinary commercial oil was administered to a dog weighing eighteen pounds. In three minutes he fell on his side in strong convulsions, and in five minutes more was dead.

The following experiments were made upon rabbits:

EXP. VII.-One drachm of the oil, not quite free from prussic acid, used in Exp. II. and III., was given to a middle-sized rabbit. No effect ensued for seventeen minutes, except rapid, rather strong, action of the heart, and quick breathing, which at that period was, 96 in the minute. In twenty-five minutes the pupils were sluggish but not dilated. The animal was dull, but moved readily when touched. It remained quite well for four hours, at which time it fed heartily. It was apparently well next morning, but died early in the subsequent day, thirty-nine hours after getting the oil. On dissection, the muscles were very rigid; there was no odour of the oil in any part of the body. The stomach was full of food, and the intestines of semifluid fæces. The mucous membrane of the stomach presented a moderate diffuse redness, but no extravasation. Both lungs were of a bright scarlet colour, and the lower lobes, on both sides, were in the congestive stage of pneumonia.

EXP. VIII. Two drachms of the same oil were given to a strong white rabbit. In five minutes it was dull, and not easily roused, breathing 76 per minute. In eight minutes it lay on its side, and did not attempt to move any of its legs. In ten minutes the pupils were closely contracted, though in a dull light-the animal was an albino. All the muscles became relaxed; it made a feeble attempt to cry; the breathing became rapid and irregular; there were twitchings of the muscles of the head and neck, and it died in sixteen minutes, without any farther approach to convulsions.

On dissection, there was a slight smell of the oil in the cellular tissue, more distinct in the blood, very marked in the abdominal cavity, and intense in the stomach, the mucous membrane of which was of a natural colour. The bladder contained some urine, with a slight smell of the oil, and yielding readily, by the usual process, the characteristic crystals of hippuric acid. This, with Exp. V., enables me to add my testimony to the observation of Wöhler and Frierichs, that the oil appears in the urine in the form of hippuric acid; but if the dose be large, that part of it passes unchanged.

EXP. IX. Two drachms of another sample of oil, entirely free from prussic acid, were given to an albino rabbit, of middle size. In seven minutes the animal passed some urine, quite free from the

smell of the oil. At ten minutes it fell languidly on its side, and lay motionless, the pupils contracted, and the ears cold. The heart's action was rapid and feeble, and the breathing exceedingly quick, short, and ultimately irregular. At nineteen minutes the animal was moribund. Being anxious to try the effects of cold affusion, so valuable in poisoning with hydrocyanic acid, I applied it to this animal. Under the action of a full stream of cold water the breathing for a while became deeper and more regular, but it soon became irregular again. The rabbit, however, did not cease to breathe till fifty minutes after getting the oil. I have little doubt that life was prolonged by the cold affusion.

On dissection, the mucous membrane of the stomach was found to be of an uniform pale pink colour, but no extravasation of blood. Both sides of the heart were much distended with blood. All the other organs were natural.

EXP. X.-Two drachms of oil, rectified by myself ten months ago, and both then and now found to be free from hydrocyanic acid, were given to a very strong buck rabbit. After the first agitation had subsided, no symptoms were observed for twenty minutes, when the animal looked dull and languid. At thirty-two minutes, however, it revived and ate a little bit of cabbage. It was watched for one hour, and during that time appeared quite well. It was again seen, after four and a half hours, apparently well, but it died in the course of the night.

On dissection, the mucous membrane of the stomach was found slightly reddened in patches. All the other organs were healthy. The bladder contained a little urine, smelling feebly of the oil.

These two last experiments show, that in rabbits death will ensue from hydruret of benzule, quite free from hydrocyanic acid. But, before fixing our ideas as to its activity as a poison, let us compare it with another volatile oil, which could have no possible connection with hydrocyanic acid. That which I used was the oil of cloves, as being, in pungency and density, the likest to hydruret of benzule.

EXP. XI.-A drachm of oil of cloves was given to a middle-sized rabbit. The breathing became rapid, as usual, but no bad effects followed. The animal was quite well at three and a half hours, fed freely, and remained well.

EXP. XII. Two drachms of oil of cloves, after an interval of two days, were given to the same rabbit. In eight minutes it began to grow very dull, the ears became cold, the heart's action was rapid and strong, the breathing slow and irregular. At twelve minutes the iris was somewhat dilated, and barely sensible to strong light. In fifteen minutes the animal lay motionless on its side; the breathing was slower (32 per minute), and more irregular. There was a temporary slight return of heat in the ears, but the breathing continued

slow and irregular; the extremities became cold, and the animal died in an hour and a quarter.

On dissection, there was found some serous effusion into the peritoneum, but no traces of inflammatory action there. The serum had a slight aromatic odour, but not recognisable as that of oil of cloves. The contents of the stomach smelled strongly of the oil. The mucous membrane of the stomach was not inflamed, being pale throughout its whole extent, but marked by numerous small spots of dark bloody extravasation into the submucous tissue. The lungs were healthy.

EXP. XIII.-Two drachms of oil of carraway were given to a dog weighing sixteen pounds. The animal, which was naturally sluggish, was very dull in thirty-five minutes, and continued so for three hours more. It vomited a little during this interval, and refused to eat, but no other effect was observed, and it quite recovered.

From these experiments of my own, and those recorded by others, I am led to draw the following conclusions:

1. That the marked difference between rectified and unrectified oil of bitter almonds, shows that the poisonous action of the latter is essentially due to the hydrocyanic acid which it contains.

2. That the oil, really free from hydrocyanic acid, in doses of a few drops, does not act as a poison on animals generally; and that the instances of fatal effects on man and animals of such doses of the unrectified oil, must be referred entirely to the hydrocyanic acid.

3. That experiments on rabbits with quantities of half a drachm and under, invariably show, that if quite free from prussic acid, such doses do not cause fatal effects.

That in larger doses (a drachm and upwards), it does, even when quite free from hydrocyanic acid, prove fatal to rabbits, but with great variation as respects the rapidity of the death, which variation is due to the physiological peculiarities of these animals.

4. That on dogs, whose organization renders them much better subjects for testing the probable effects of the substance on man, doses, even so large as three drachms of the oil, entirely or nearly free from prussic acid, produce no other effect than a little vomiting, and do not cause death, or even dangerous symptoms.

5. That experiment shows, that if this substance is to be called a poison at all, it must be regarded as one of no great activity; but that, in reality, it cannot, even on the ground of its effects on rabbits, be styled a poison, without including under this denomination many other substances, such as oil of cloves, which cannot be regarded as poisonous, in the common sense acceptation of the term.

6. That the use of the purified oil to make flavouring condiments is open to no objection which would not apply to ordinary aromatic volatile oils, and that the spirituous solutions sold for this purpose, if made of properly purified oil, are not dangerous.