An "Embrocation" is a preparation of a thinner consistence. LOTIONS. External applications or washes, generally consisting of simple solutions of medicinal substances, and usually applied by wetting a piece of linen. OINTMENTS. Fluid Soft unctious substances applied to the skin by inunction. They should have the consistency of good butter. Where the active ingredients are pulverulent, fresh lard free from salt is the best excipient. or semi-fluid ingredients require suet, or a mixture of suet and lard, or sometimes wax. On the other hand, if the ingredients form too dense a mass, oil may be added. A good vehicle for active ingredients is simple ointment. "Cerates," so called from containing wax, are of a firmer consistence than ointments. FUMIGATIONS. Vapours or gases extemporaneously set free for deodorizing or disinfecting purposes, or to produce medicinal action on certain parts of the body with which they are brought into contact. In the following Lessons we will endeavour to apply the principles, the study of which has hitherto occupied our attention. I purpose devoting our concluding Lessons to examples and exercises; and I trust that the arrangement I have adopted will be found to conduce to convenience, and to invest the subject with additional interest. ANTACIDS. Antacids are medicines which counteract acidity, acting chemically by neutralizing the acid. "Direct" antacids are those which directly neutralize the acidity of the stomach and intestines; "Remote" antacids are those which increase the normal alkalinity of the blood, and, through it, correct acidity of the secretions. Antacids may be divided into three classes-1. Those which are both direct and remote. 2nd. Those which are direct but not remote, as ammonia and its salts. 3rd. Those which are remote but not direct, for instance potash or soda combined with some vegetable acid, as citric or tartaric. In the latter case the vegetable acid becomes converted into carbonic acid in the system. The physician will remember that antacids are only palliative in their action. The administration of alkalies should not be continued too long; when a course of alkalies is indicated, they should be combined with some vegetable tonic, and they should be discontinued at intervals. F The following is a list of the antacids with their pharmacopoeial preparations and doses : Ammon. Liquor. mx.-xxx. Spt. Ammon. Ar. mxxx.—3i. Calcis Liquor. 3i.—iv. Calcis Liquor Sacch. mxv.-zi. Mist. Creta. Zi.—ii. Pulv. Creta Ar. gr. x.- -zi. Pulv. Crete Ar. c. Opio. gr. x.-xxx. Lithia Carb. gr. iii.—vi. Liq. Lithia Efferv. 3v.-x. Lithia Cit. gr. v.—x. Magnesia. gr. x.—zi. Magnesia Levis. gr. x.—3i. Magnesiæ Carb._gr. x.—3i. Magnesiæ Carb. Levis. gr. x.-—zi. Liq. Magnes. Carb. Zi.—ii. Potassæ Liquor. mxv.-3i. Liq. Potassa Efferv. Zv.-x. Potassæ Carb. gr. x.-xxx. Soda Liquor. mx.—zi. Soda Bicarb. gr. x.-31. Liq. Soda Efferv. 3v.-x. Trochisci Soda Bicarb. 1-6. Soda Carb. gr. v.-xxx. Soda Carb. Exsiccat. gr. iii.—x. REMOTE ANTACIDS. Salts of potash or soda combined with a vegetable acid, as citric or tartaric. 1. Prescribe a mixture for a case of acidity with flatulent distension of the stomach. R Liquoris Ammoniæ, drachmam. Mistura Amygdala, uncias octo. Misce. Fiat mistura. Capiat cochlearia duo magna bis terve in die. In this case we select ammonia as it is a volatile antacid; carbonate of ammonia would be inadmissible, as the evolution of carbonic acid in the stomach would increase the flatulence. The student will notice that we have prescribed the ammonia in a large quantity of bland fluid, a precaution which it is always well to observe in administering liquor ammonia. B 2. Prescribe Carbonate of Ammonia in effervescence. Ammoniæ Carbonatis, grana sex. Syrupi Aurantii, drachmas duas. Aquæ, drachmas decem. Misce. Fiat haustus, cui, tempore capiendi, adde Succi Limonis recentis cochleare medium unum, et in effervescentiâ sumatur. Not unfrequently at examinations and in practice you will be required to prescribe certain substances in a state of effervescence. The following table, showing the proportions which should be ordered to produce exact neutralization, will be found of use: 3. Prescribe a mixture containing Carbonate of Ammonia with a salt of iron and a vegetable infusion. R Ammoniæ Carbonatis, semidrachmam. Ferri Tartarati, grana quadraginta. Syrupi Zingiberis, unciam. Infusi Quassiæ, ad uncias octo. Misce. Fiat mistura. Capiat cochlearia duo magna bis in die. This prescription serves to illustrate several important facts. It shows that carbonate of ammonia, although incompatible with other salts of iron, may be given with ferrum tartaratum. Syrup of ginger is preferred to syrup of orange, which is turned black with the iron. Infusion of quassia which does not contain tannin is an excellent vehicle for iron salts. 4. Prescribe an Alkali in combination with Sulphate of Magnesia. Soda Bicarbonatis, drachmas duas. Infusi Cascarillæ, ad uncias octo. Misce. Fiat mistura, cujus capiat cochlearia duo ampla sextis horis. |