Finally, certain fumes and vapours may be inhaled through a common smoking pipe, as those of stramonium and camphor for example, the former being set on fire in the bulb, the latter volatilized in the same position by the current of air passing through it. Another mode of effecting the same object is by the smoking of cigarettes, made by rolling into the form of small cigars narrow strips of paper, previously impregnated with a solution of the substance the fumes of which are to be inhaled, and then drying them.

Use of liquids in the form of spray. Reference has already been made to a new process by which liquids are brought into contact with the air-passages, mixed, in a state of extremely minute division, with atmospheric air, or aqueous vapour, but still retaining the liquid form. Liquids in this condition are said to be pulverized, atomized, or nebulized; and the instruments by which the effect is produced are variously named atomizers, pulverizers, or nebulizers; the first of these terms being preferred by English writers, the second by the French, and the third by the Germans. As this subject has been pretty fully considered in the recently published edition of my Treatise on the Practice of Medicine (6th ed., vol. i. p. 949), it is unnecessary to do more here than to make a few observations, calculated to give the reader a general knowledge of the subject. It is well known that various substances in solution, or otherwise in the liquid state, often have a curative effect when brought into contact with local diseases, whether of the skin, or of accessible mucous surfaces. It has, therefore, been a desideratum to find a method by which these substances might be applied to the air -passages within or beneath the larynx. Attempts have been made to accomplish this object, to a certain extent, by the injection of liquids into the trachea and bronchia, or by penetrating the rima glottidis with moistened sponge at the end of a long handle; but the inconvenience if not danger of these methods is very great, and their success very problematical. But when the idea suggested itself that the end might be safely attained by imitating certain processes of nature, by which liquids in a state of extremely minute division, still holding soluble substances in solution, might be intimately mixed with air, and in this state safely introduced into the air-passages in ordinary respiration, as when we inhale the spray from breakers on the sea-shore; it was an obvious conception, that this process might be artificially imitated, and medicinal liquids in this way be brought into direct contact with the interior of the lungs. Two methods of accomplishing this object suggested themselves to experimenters; one by causing a small stream of the liquid to be forcibly impelled against a solid body, and thus to be broken into minute particles and diffused in the surrounding air; and another, by which a strong current of air should, at the point of issue from a tube, be made to bear upon a slender column of liquid, and to carry this along with it in the form of spray, expanding into a cone with a constantly increasing base till lost in the atmosphere. Instruments were contrived on both of these principles, and have come into extensive use; those, however, based upon the second plan being generally preferred. For an account of the instruments and their mode of use, I must content myself with referring to my Treatise on the Practice, and to the various published monographs on the subject.* There is reason to believe that good may be effected by this method of inhalation, not only by the curative influence exerted in the diseased membrane by the contact of the medicine, but also through its absorption into the circulation, and the exercise on the system at large of its peculiar powers. It has been objected to this mode of medication, so far as concerns its action on the pulmonary air-tubes, that the pulverized liquid never really passes below the glottis; being deposited before it reaches the respiratory passages. This, however, is not exactly true. Abundant proof has been offered that some substances do in fact reach the bronchia, and beneficial therapeutical effects have been obtained; but it is true, nevertheless, that much of the liquid separates before reaching the interior of the larynx, and very little of it is carried to the ultimate ramifications of the bronchia; so that wo must be satisfied with less practical result, as regards pulmonary diseases, thai) may have been anticipated by some in the beginning. By certain modifications of the apparatus, the pulverization may be effected in the cavity of the mouth, and even in the fauces; so that the spray may be brought to bear with its entire intensity, upon the pharynx, the posterior nares, the entrance of the Eustachian tube, and the exterior glottis; and will probably also pass more deeply into the air-passages than when inhaled, as it ordinarily is, from without. The particular medicines adapted to this mode of exhibition, and the strength of the solutions to be atomized, will be more appropriately considered under the heads of the several medicines employed.

* Among these may be mentioned Chisholm's inhaler(N. Y. Medical Record, Jan. 1, 1867, p. 509); Nelson's inhaler (Lancet, Feb. 11, 1865); Curtis' s inhaler (Med. T. and Gaz., Dec. 1861, p. 624); and Thompson's hydro-pneumatic inhaler (Lancet, Jan. 28, 1860), which, however, acts on a different principle. (Note to the third edition).

* I would especially call attention to two essays; one by Dr. J. M. Da Costa, of Philadelphia, in the N. Y. Med. Journ. (Sept. and Oct. 18GG, pp. 401 and 29); the other by Dr. Ephraim Cutter, of Boston, in the, Med. and Surg. Reporter (July 14 and 21, 1866, pp. 38 and 60). In the Boston Med. and Surg. Journal (Dec. 27, 1866. p. 434) a variety of the apparatus has been described, denominated the "hydrostatic atomizer," in which the pressure of a column of water is employed in order to give requisite force to the current of air, instead of pressure by the hand, by a forcing pump, or by steam, which is employed in other instruments.

Besides the remedial advantages above mentioned as resulting from this method of applying medicines, other useful results have been obtained. For disinfecting purposes the atomizer has been found very effi-eient, diffusing as it does the disinfecting material equably through the air of the apartment, and thus causing it to act on every particle of the offensive or noxious agent. Another effect is the production of extreme cold by the rapid evaporation of volatile liquids, brought into this state of minute division; and the anaesthetic influence of the cold, thus generated upon the surface of the body, has been taken advantage of to a considerable extent by surgeons. More will be said of both of these effects hereafter in this work.