The act of blowing a vapour or powder into some cavity, or on some particular part of the body; e.g., air blown into the mouths of new-born infants, to excite the respiratory function. In modern practice the term is chiefly applied to the following mode of applying solid substances to the larynx, &c., as proposed by Trousseau and Belloc* Alum, the Subnitrate of Bismuth, &c., having been reduced to impalpable powders, are put into one end of a reed or glass tube, and the other is carried back as far as possible into the mouth. After a full expiration, the patient closes his lips around the tube, and inspires suddenly and forcibly through it, by which some of the powder is carried into the larynx and trachea. The cough which is excited should be restrained as much as possible, to prevent the too speedy expulsion of the medicine. The Subnitrate of Bismuth may be used pure. Calomel should be diluted with 12, Red Precipitate, the Sulphates of Zinc and Copper with 36, Alum with 2, Acetate of Lead with 7, and the Nitrate of Silver with 22, 36, or 72 times, their respective weights of sugar. The powders should be impalpably fine, as the least roughness excites such efforts to cough, as to insure the expulsion of the powder. They are chiefly used in affections of the larynx and trachea. (Dr. Williams.)

3177. Issues and Setons, considered as therapeutic agents,

* Trait de la Phthisie Laryngee, 8vo, Paris, 1837.

Lib. of Med., vol. i.

closely resemble one another in their operation and effects, and may be conveniently considered together. They are mentioned in the earliest records of medicine, and their use doubtless arose from observing how constantly nature, by the formation of natural issues, as ulcers, &c, relieves the system from a tendency to certain diseases; how much these natural issues mitigated the severity of the symptoms, when the disease is established; and how frequently serious, and even fatal effects follow their removal, either spontaneously or by artificial means. In employing these agents, we closely follow nature, and the benefit derived from them is very great, particularly when compared with the very little expense to the strength of the constitution which they occasion. They are purely chronic remedies, suitable only to chronic diseases, in which they appear to act chiefly as derivatives, and partly perhaps also as evacuants.

3178. Observations On Their Use

1. In acute diseases, the benefit from setons or issues is very small; their use is chiefly confined to chronic diseases.

2. Never place them over projecting points of bone, or over the bellies of muscles, or in any part which is much interfered with by muscular action, or they may degenerate into ill-conditioned ulcers.

3. Cleanliness Is Of The Utmost Importance

Issues should be dressed at least once daily.

4. Care is necessary that the sore does not discharge too profusely; a drachm of pus in the day is the utmost that can be borne by most constitutions.