Avicenna, Averrhoes, and Haly Abbas direct a traveller to get bled before entering upon a journey; and, in certain cases, this might be a very proper practice to prevent the blood from being inflamed by violent exercise, but, on the other hand, unless judiciously applied, it might bring on such debility as would render the traveller unable to undergo the necessary fatigue. They recommend him to hold in his mouth a small ball of the trochisk of camphor. The Arabians, it is to be recollected, maintained that the action of camphor is frigorific. Instead of the draught mentioned by our author, Avicenna recommends vinegar and water. He recommends little food, but of good nourishment; and forbids pot-herbs and fruit. With regard to the treatment of the feet, they are to be rubbed until they become warm, and then anointed with hot fragrant oils. When the feet have suffered from cold, some, he says, put them into cold water, and are thereby relieved, in like manner as congealed fruits are sometimes restored. When the water for drink is bad, he advises to get it distilled. Haly Abbas gives very minute directions for the conduct of travellers. Like our author, he advises them to gird the body with a swath or band, and to use a staff. He forbids them to begin a journey either fasting, or in a state of repletion with food. Exposure to the sun, he says, is apt to occasion hectic fevers, headach, consumption, and dryness of the body. He directs them to have the head covered. When hurt by exposure to heat, he advises cold water, or any other thing of a cooling nature to be poured over the head. After exposure to cold, he recommends the hot bath. (Pract. i, 31.)