=Tannic Acid, Tannin.=—This is employed externally as an astringent and styptic, and internally as an astringent in atonic diarrheas. It is used in the form of a gargle or in troches in relaxed conditions of the throat, in solution to prevent bed-sores, and in the form of ointment or suppositories for the relief of internal piles. _Dose_, 1 to 10 grains. =Trional.=—This remedy resembles sulphonal in action, and is used for the same purpose. It may also be given in the same _dose_ and manner as sulphonal. =Urotropin.=—This compound, prepared by the action of ammonia on formaldehyd, is employed as a powerful urinary antiseptic in _doses_ of from 3 to 5 grains (0.2-0.3 gm.). Large doses may cause pain in the bladder, frequent urination, and bloody urine. =Veratrum Viride.=—This is the root of a North American herb. Its action resembles that of aconite in that it depresses the heart and slows the pulse. It is, however, more nauseating than aconite, and when locally applied does not cause numbness, tingling, and anesthesia. Large doses cause vomiting, muscular weakness, dizziness, sweating, failure of pulse, and collapse. It is used as a sedative in acute inflammatory diseases to subdue overaction of the heart. The _dose_ of the _tincture of veratrum viride_ (tinctura veratri viridis) is from 1 to 5 minims (0.06-0.3 c.c.). DOSAGE. The following general rules will aid the student in remembering the safe dose of many important preparations: 1. Tinctures of very active drugs, such as opium, digitalis, belladonna, physostigma, nux vomica, gelsemium, arnica, and capsicum may be given in _doses_ of from 5 to 20 minims (0.3-1.2 c.c.), except the _tinctures of aconite_, _veratrum viride_, _iodin_, and _cantharides_, the _dose_ of which is from 1 to 5 minims (0.06-0.3 c.c.). 2. Tincture of less active drugs, such as gentian, calumba, krameria, quassia, valerian, cinchona, kino, may be given in _doses_ of from ½ to 1 dram (2-4 c.c.). 3. Solid extracts of active drugs may be given in _doses_ of from ⅙ to ¼ of a grain (0.01-0.016 gm.). 4. Solid extracts of less active drugs may be given in _doses_ of from ½ to 5 grains (0.03-0.3 gm.) or more. 5. Dilute acids (hydrochloric, nitric, nitrohydrochloric, sulphuric) may be given in _doses_ of from 5 to 20 minims (0.3-1.3 c.c.), except _dilute hydrocyanic acid_, the _dose_ of which is from 1 to 5 minims (0.06-0.3 c.c.). 6. All medicated syrups, except the _syrup of iodid of iron_ and the _compound syrup of squill_, may be given in _doses_ of 1 to 2 drams (4-8 c.c.) or more. 7. All infusions may be given in _doses_ of ½ to 1 ounce (15-30 c.c.) or more, except the _infusion of digitalis_, the _dose_ of which is from 1 to 4 drams (4-15 c.c.).