Where the body is exposed to miasmata, and a great deal of exercise taken at the same time, broths, a little wine, or malt liquors, may be used with the fruits and garden vegetables of the season, with safety and advantage. The change from a full to a low diet should be made gradually. When made suddenly, it predisposes to an attack of the disease. 2. Laxative medicines. Hundreds, perhaps thousands, of the citizens of Philadelphia were indebted for their preservation from the yellow fever to the occasional use of a calomel pill, a few grains of rhubarb, or a table-spoonful of sweet, or castor oil, during the prevalence of our late pestilential fevers. Even the air of Batavia has been deprived of its poisonous quality, by means of this class of medicines. A citizen of Philadelphia asked a captain of a New-England ship, whom he met at that island, how he preserved the whole crew of his ship in health, while half the sailors of all the other ships in the harbour were sick or dead. He informed him, that it was by giving each of them a gentle purge of sulphur every day. 3. A plentiful perspiration, or moderate sweats, kept up by means of warm clothing and bed-clothes. The excretion which takes place by the skin, is a discharge of the first necessity. I have never known an instance of a person's being attacked by the yellow fever in whom this discharge was constant, and equally diffused all over the body. Its effects are equally salutary in preventing the plague. So well known is this fact, that Mr. Volney informs us, in his Travels into Egypt, that the common salutation at Cairo, during the prevalence of the plague, is, "Do you sweat freely?" For the purpose of promoting this excretion, flannel shirts or waistcoats worn next to the skin have been found more useful than linen. As the perspiration and sweats, which are thus discharged in a pestilential season, are often unusual in their quantity, and of a morbid quality, clean body-linen or flannel should be put on every day, and where this is not practicable, that which has been worn should be exchanged every morning and evening for that which has been exposed during the previous day and night, in a dry air. 4. Blood-letting. In addition to the authorities of Dr. Haller and Dr. Hodges, mentioned in another place[16], in favour of this remedy, I shall subjoin a few others. Dr. Mitchell, in his Account of the Yellow Fever which prevailed in Virginia, in the year 1741, informs us, that it was often prevented in persons who were under the influence of its remote cause, by the loss of a few ounces of blood. It was formerly a practice among the physicians in St. Domingo, to bleed whole regiments of troops as soon as they arrived from France, by which means they were preserved from the malignant fever of the island. [16] Account of the Yellow Fever in 1793, vol. iii.