COMMENTARY. Galen gives some ingenious remarks on the causes of coughing. He states that when any substance becomes fixed in the trachea, as it is a cartilaginous and hard tube, and incapable of contraction, nature brings on coughing, by which a violent expiration of air is induced. A cough, then, is nothing but a violent expiration by which nature endeavours to expel any body that obstructs the air-passages; and, when she cannot accomplish this at the first effort, she repeats it once and again until she effect her purpose. He goes on to state, that such fluids as are very watery, instead of being brought up, are merely divided or cut asunder by the current of air, while such as are thick and viscid, adhere so closely to the sides of the windpipe that they cannot be removed, and hence violent efforts are necessary to effect the discharge of them. (De Causis Sympt. ii, 4.) He treats fully of compositions for coughs in his work ‘De Comp. Med. sec. Loc.’ (vii.) See the 28th Section of the Third Book. Avicenna recommends cough pills and lohocks made with poppies, the cold medulla of fruit, starch, and the like. (iv, i, 2.) The prescriptions of Serapion contain liquorice, sweet almonds, tragacanth, and the like. (De Antidotis, vii, 17.) Those of Haly Abbas are very similar. (Pract. iii, 22.) A receipt is given by Rhases for cough pills, the principal ingredients of which are tragacanth, sweet almonds, poppy seed, gum Arabic, and Armenian bole. (Divis. i, 52.) Many such receipts are given by Myrepsus. SECT. XLIX.—ON SNEEZING. Sneezing frequently occurring in fevers is troublesome, for it determines to the head and weakens the strength, and, in some cases, it produces a discharge of blood. Such are the bad effects of sneezing, which ought therefore, to be contended against. It is restrained by rubbing the nose, forehead, and eyes; by yawning, frequent friction of the roof of the mouth, eructation, stretching of the loins, raising the head, turning to the side, gently chafing the extremities, anointing the masseter muscles, pouring hot oil into the ears, applying a warm cushion under the chin. It is proper to avoid being roused suddenly from sleep, and also smoke, dust, acrid smells, pepper, castor, mustard, and mint. The smell of apples and polenta is proper, for it blunts the desire of sneezing. The empty sea-sponges do the same. When there is a frequent desire of sneezing without the ability, let the lips be composed, let the patient smell to acrid substances, and let the mind be relaxed. * * * * * COMMENTARY. Galen explains that sneezing is a still more violent effort of nature than coughing, and that its intention is to remove irritating matters from the parts about the nose. (De Caus. Sympt. ii, 4.)