I place these together, because, so far as concerns their operation on the air-passages of the lungs, they are almost identical in their effects. Elsewhere it has been stated that these substances are stimulant to the circulatory system, with a disposition to excite the different emunctories, in all the forms of chronic bronchitis, even without any symptoms of hectic, which have been called pituitous catarrh, bronchorrhoea, humoral asthma, and tussis senilis, all characterized by copious expectoration, these medicines may be employed, whenever there is no acuteness in the symptoms to contraindicate them.

especially the kidneys. They exercise a similar, though comparatively feeble influence on the bronchial mucous membrane. it is probable that all their effects, both local and general, are dependent almost exclusively on their volatile oil, which enters the circulation, and escapes, unchanged or modified, through various outlets, exciting the several tissues in its passage. The lungs afford one of these outlets, and are, therefore, subject to this special influence of the oil. Besides this, they feel, together with all the other vascular tissues of the body, the stimulant action of the oil circulating through them with the blood. There is thus a double action upon the air-passages, which is sometimes available for important therapeutic purposes.

Copaiba and the turpentines may be used in all chronic bronchial and laryngeal inflammations, in which activity of excitement or acuteness of inflammation is wholly past; but especially when there is coincident general debility. They are specially adapted to those old cases of catarrh or bronchitis, in which there is copious expectoration of mucous, muco-purulent, or purulent matter, with general debility, emaciation, night-sweats, etc.; and which bear a close resemblance to pulmonary consumption in their external aspect, though toto coelo different in their real nature.

They may be used by the stomach or by inhalation. The turpentines, administered in the latter method, have been recommended in gangrene of the lungs.

Copaiba is generally most conveniently given in emulsion, made by suspending it, by means of gum arabic and loaf sugar, in mint-water; and may frequently be combined with laudanum, or some other preparation of opium, and with other expectorants, to give it a more decided direction to the lungs. From ten to twenty minims may be administered three or four times a day, or, in cases of urgency, every two or three hours. Or its volatile oil may be substituted in from one-third to one-half the dose.

Turpentine may be used in the same way. The Canadian turpentine is the most elegant and agreeable of these oleo-resins; but any one of them may be employed; our common white turpentine, Strasburg turpentine, Venice turpentine, or the Chian. They may be given also in the form of pill, and those having the liquid form in electuary; but the emulsion is on the whole the best method, as likely to be most acceptable to the stomach. The volatile oil (Oleum Terebinthinae) might be substituted; but, from the rapidity of its absorption, it is more stimulant in its operation, and more likely to affect the urinary passages disagreeably. The dose of the turpentines is from a scruple to a drachm.

The following are substances analogous to the turpentines in their effects upon the chest, and are occasionally used for the" same purpose.