Active Ingredients. - The leaves possess a bitter and somewhat acrid flavor, and the odor evolved, when they are bruised, is offensive and characteristic. Drying dissipates the odor, but the taste remains, and then exhibits a certain amount of astringency. Their most important constituent is amygdaline, the formula of which, according to Wohler and Liebig, is C20H17NO11; a substance identical with the glucoside of that name which is found in bitter almonds, although not crystalline, like the latter, but amorphous. Amygdaline is capable of a variety of chemical transformations, but the most interesting is that which it undergoes when mixed with certain albuminous matters and with water, which is also present in the almonds. In bitter almonds it unites, under these circumstances, with emulsine, and the immediate result is the formation of hydrocyanic acid, bitter almond oil, sugar, and (probably) formic acid. A similar kind of transformation takes place when laurel leaves are distilled with water, although it is not known what is the albuminoid body that here performs the functions of the emulsine in bitter almonds. The consequence is that laurel-water contains a small (but unfortunately a varying) proportion of prussic acid, and, so far as is known, this is the ingredient which alone gives it power to affect the system.

Physiological Action. - The leaves and the kernels of the fruit possess poisonous properties. "Laurel-water," prepared from the former, is similar in action to prussic or hydrocyanic acid, being capable of inducing sudden insensibility, and even of producing death within a few minutes. The parts of the body particularly affected by the swallowing of an overdose are the brain and the true spinal system. The cerebral affection is indicated by pain in the head, insensibility, and coma; and disorder induced in the spinal system has corresponding evidence in tetanic convulsions.

Taken in non-poisonous or medicinal doses, laurel-water occasions nausea, accompanied, perhaps, by vertigo, and pain in the stomach; the first effects being increased secretion of saliva, irritation in the throat, nausea (very frequently), disordered and laborious respiration, pain in the head, giddiness, obscured vision, and sleepiness. If the dose be increased, there is decided vertigo, faintness, and perhaps rapidity of pulse, with sickness, and a sense of constriction at the pra?cordia; while a dose that stops short only of being fatal, occasions insensibility and extreme feebleness of the action of the heart.

Swallowed in poisonous quantity, other symptoms quickly show themselves. The respiration becomes difficult and spasmodic; the pupils are usually dilated, though sometimes contracted; the pulse becomes small or even imperceptible; and presently there are tetanic convulsions, with insensibility, and death quickly follows. The proximate cause of death, in most cases, is obstructed respiration; but in some instances it is referable to stoppage of the action of the heart.1

Regarded as a medicine, cherry-laurel water, like prussic acid, is said to be narcotic, sedative, and anti-spasmodic, but it does not possess the power of lessening pain in general; nor has it the property of inducing sleep in a direct manner, in the way, for instance, that is effected by opium. Neither, again, has it the power of controlling the pulse, such as we find possessed by digitalis.

It is remarkable that the pulp of the fruit is not only free from the poisonous properties of the leaves and kernels (as happens also with the fruit of the yew-tree), but is wholesome and palatable.

Therapeutic Action. - Laurel-water may be employed in all cases where it is customary to resort to prussic acid; and emphatically when there is need of a sedative narcotic. The results of the administration are rendered uncertain, however, by the varying- strength of the medicine, the energy of which is greatest when moderately young leaves are employed, or when the water has been prepared quite recently from dried ones. It is a useful remedy in gastralgia, pyrosis, hiccough, and some other forms of dyspepsia. Palpitation, depending upon dyspepsia, is, in common with the other symptoms, greatly mitigated by the use of it. The powers of this medicine are again very conspicuously shown in cases of vomiting unconnected with inflammation of the stomach. Frequently, as with pregnant women, it has been found to arrest, at the first few doses, vomiting which had existed for several weeks, and which arose merely from morbid irritability.

As with prussic acid, laurel-water will not, however, mitigate pain felt in the intestines. Not being a general anodyne, its employment for the relief of pain is proved by experience to be often useless; though the attacks of pain which occur in angina pectoris, and which, in situation and course, so closely resemble gastrodynia, are often more quickly alleviated by laurel-water, or by prussic acid, than by any other agent at command. It must be added that laurel-water sometimes very quickly allays and even removes tic-douloureux.

Hooping-cough, etc. - I have frequently employed laurel-water, with advantage, in hooping-cough, and in the affection termed "spasmodic cough," in both instances as a substitute for prussic acid; also, in cases of inflammation of the chest, after the subsidence of the acute symptoms. In repeated catarrh, and in chronic bronchitis, small doses of the same medicine often prove eminently serviceable; it will also relieve some of the more distressing symptoms of phthisis, and is valuable therefore in its competency to afford temporary comfort.

1 The most interesting case of fatal poisoning with laurel-water recorded is that of Sir Theodosius Broughton, who was murdered in this way in 1781.

Prurigo, etc. - In prurigo, impetigo, inveterate psoriasis, and other cutaneous affections, attended by severe itching and tingling, laurel-water again affords great relief to the patient. The powdered leaves of the tree, mixed with flour or linseed-meal, have been employed as a poultice for ulcers.

But for the procuring of sleep, for the relief of pain in general, or as a remedy for diabetes, laurel-water, like prussic acid, though often recommended, will be found a poor substitute for other drugs.

Preparations and Dose. - Aqua Lauro-cerasi (B. Ph.), mv. xxx. (.30 - 2.). The strength of this preparation being very uncertain, caution is required in its use. The Codex directs that the "Eau distillee de Laurier-cerise " shall be adjusted by analysis so as to contain .05 per cent. of hydrocyanic acid.