This section is from the book "Dental Medicine. A Manual Of Dental Materia Medica And Therapeutics", by Ferdinand J. S. Gorgas. Also available from Amazon: Dental Medicine.
Cod-liver oil is obtained from the liver of the cod, Gadus morrbuae, and is in the form of a fixed oil, containing biliary principle, traces of iodine, bromine, phosphorus, lime, magnesia, iron, soda and sulphuric and phosphoric acids; also a principle known as gaduin. By distillation with ammonia, it yields propylamin. The pale oil is considered to be the best for internal use, and is the officinal preparation. Iodine, phosphorus, bromine and iron are often combined with cod-liver oil, but are considered to add nothing to its therapeutical powers. The special medicinal value of this oil depends upon the gaduin and propylamin, which are constituents of bile, iodine, phosphorus, bromine, etc., as well as upon the common ingredients of animal fat. The phosphates, hypo-phosphites, or the lacto-phosphate of lime are often combined with cod-liver oil, with excellent effects.
Cod-liver oil is considered to be a valuable remedy in certain forms of phthisis, such as the chronic forms - chronic tuberculosis and fibroid lung; but not in acute phthisis and caseous pneumonia; also in chronic affections of the brain and nervous system, and such skin diseases as lupus, ecthyma, psoriasis, etc. It is also employed in sequels of scarlet fever, chronic bronchitis, emphysema, chronic rheumatism and rheumatic arthritis, strumous synovitis, scrofula, caries and necrosis of bone; scrofulous, rickety infants and chlorotic girls derive benefit from warm baths and inunctions of the oil ; also lean persons. Inunction with cod-liver oil is also useful in rubeola, scarlatina, erysipelas, high fevers, catarrhal attacks, scrofula, phthisis, chronic dysentery, etc. It builds up the tissues, repairs waste and supplies nervous, muscular and digestive power. It may be administered in ale, beer, coffee, lemon juice, hot whiskey punch, compound spirits of lavender and brandy, or washing out the mouth with whiskey or brandy, or as an emulsion made with glycerine and yolks of eggs, and flavored. It is also used in the preparation of bread in form of rolls; ether added to it promotes its digestion; fifteen minims of ether to every half-ounce of the oil.
Of cod-liver oil, to