respect to its utility may now be collected. As a palliative in certain spasmodic coughs, there is reason for supposing that it _may sometimes_ be useful, but in that species of pulmonary irritation for which it was at first so greatly extolled, I will venture to assert that it is far inferior in efficacy to well directed doses of _Conium_. But there is another class of diseases in which its exhibition is said to prove useful, in dyspeptic affections attended with heartburn; where it is supposed to be capable of reducing the morbid irritability of the stomach, and thereby of enabling the juices of that organ to be more slowly secreted and of a more healthy character. Dr. Elliotson has published the result of his treatment of stomach complaints with this medicinal agent, and would appear to appropriate to himself the merit of originating the practice, a claim which Mr. Thomson, in the third edition of his Dispensatory, refuses to concede.[344] As a local remedy, prussic acid has also received no small share of commendation, and it has been said that it is the only application that can be depended upon for allaying the cutaneous irritation so frequently attendant upon certain impetiginous affections. It must, however, be confessed that this medicine is rapidly declining in popularity.[345] Any prejudice raised against it, upon the ground of its poisonous activity in large doses, is too absurd to be believed; the knife and the caustic are unquestionably powerful, and may therefore become dangerous instruments; but who ever blames the surgeon for employing a sharp knife or an active caustic, seeing that both are to be directed by his eye, and guided by his hand? FORMS OF EXHIBITION. It may be conveniently administered in any liquid vehicle, as distilled water, camphor mixture, or in some vegetable infusion. See _Supplementary Formulæ_, 1, 2, 3. A question has lately arisen whether the effects of the prussic acid might not be more conveniently ensured by the administration of some vegetable[346] in which it exists as a native ingredient; a company of associated Physicians, Surgeons, and Naturalists at Florence, have accordingly expressed their joint opinion, that the essential oil of the _Prunus Lauro Cerasus_ is to be preferred in medical practice to all other preparations which contain the hydro-cyanic acid; for, say they, unlike the distilled water of the plant, and pure prussic acid, it contains the same proportion of active matter, and of the same power, whether recently prepared or not; whether made in one place or another; or whether it has been exposed or not to the air, light, or heat. They are also of opinion that olive oil forms the best vehicle for its exhibition in the proportion of one ounce to twelve drops of the essential oil. Other practitioners again prefer _Laurel Water_, made by distilling two drachms of the fresh leaves chopped, with four ounces of water, recommitting the distilled water twice afterwards on the same quantity