* _Arsenic._—Dose, one-sixtieth to one-fifteenth of a grain. Is a powerful and poisonous drug, and should be taken with caution. It is useful in chronic malaria, and in anæmia and debility, especially that following an attack of fever. It is best combined with iron in tablet form—iron and arsenic tablet—two of which may be taken twice a day, after food, for a week. This is a good general tonic. _Aspirin._—Dose 5 to 15 grains. Should be taken with a drink of water. Useful in rheumatic and febrile conditions; often relieves headache and the feeling of discomfort associated with chill. It is apt to be depressing in large doses, and some persons do not tolerate it well. Speaking generally it may be used in those conditions in which salicylate of soda is indicated. _Bismuth carbonate._—Dose, five to twenty grains. Useful in dyspepsia, pain in the stomach, vomiting and diarrhœa. The drug is heavy, and therefore gum or starch water should be used to suspend it. It is often combined with opium and bicarbonate of soda to check vomiting and diarrhœa. Bismuth may also be used as a dusting powder. _Boric acid, or boracic acid._—Chiefly used in solution, for its mild antiseptic properties, as a gargle, injection, eye lotion, or mouth wash. On the same account, it is used for washing wounds, or syringing out ulcers, or sore and inflamed ears. It is practically non-poisonous. Lotions should contain from five to ten grains to the ounce. Boric ointment is a useful dressing for sores, burns, or wounds; it may be made by adding one part of powdered boric acid to nine of vaseline or fat. Equal parts of finely-powdered boric acid, zinc oxide and starch makes a good dusting powder for moist eczema, bed-sores, chafes, and perspiring feet. Boric lint (lint impregnated with boric acid) is useful as a dressing for wounds, ulcers, and abrasions. Boric wool is absorbent cotton-wool impregnated with boric acid, and is the most generally useful antiseptic wool. _Bromides._—The bromides generally used are those of potassium, or ammonium. Dose in either case, five to twenty-five grains. They are sedatives, and are used in convulsions, epilepsy, and delirium; they relieve headache, especially if taken with sal volatile, and may be combined with chloral (_see_ Chloral). The bromide of ammonium is less depressing than the bromide of potassium. _Calcium sulphide, i.e., sulphurated lime._—Dose, a quarter to one grain three times a day. Useful for those who are suffering from boils or carbuncles. * _Calomel, or subchloride of mercury._—Dose, two to five grains. Calomel may be used in almost all cases requiring an aperient; its action will be assisted by giving fruit salt, or citrate of magnesia, four hours later. In cases of insensibility or delirium it is specially useful, for the powder may be placed on the back of the tongue, and it will be swallowed unconsciously. Four grains of calomel may usually be given with advantage, at the beginning of a malarial attack.