There is a broad but not commonly recognized distinction between what constitutes a medicine and a food. All the materials that normally enter into the composition of the living body, and are necessary to the maintenance of health and strength, may be property classed as foods, whether they be obtained from the animal, vegetable, or mineral kingdoms; thus the iron, sulphur, phosphorus, lime, potash, etc., required by the system usually exist in and are organically combined with the various foods in common use, and they are perhaps quite as essential to the physical well-being as albuminoid, fatty, and saccharine matters. When the system is suffering from lack of any of the above mentioned chemicals, their administration is to be regarded as the giving of nutritive substances, although they be prescribed by a physician in divided doses and procured from a pharmacist.
On the other hand, a medicine is any substance that does not naturally enter into the composition of the body, but which has the power, when skillfully used, to modify the physical processes so that physiological disorder - disease, shall be replaced by physiological harmony - health. Belladonna, hyoscyamus, opium, etc., are familiar examples of medicaments. Therefore a food is any substance that is capable of directly contributing to the nutrition of the body, and medicine is a substance competent, under proper conditions, to secure the same results indirectly. Viewed in the light of the above definition, cod-liver oil is to be regarded as a very valuable food, as well as a most effective remedy both for the prevention and cure of consumption.
I have previously stated that food is divided by physiologists into three great classes. The albuminoids are used to build up the organism, while the fatty and saccharine are burned in the body to keep it warm. Although these are the chief functions devolving on the above mentioned food elements, yet they are mutually interdependent on each other for the proper performance of their several offices. Thus the albuminoids cannot undergo the wonderful vitalizing process necessary to fit them to enter into and form part of the living body, except an adequate quantity of fatty matter be present to assist in the vital transformation. On the other hand, the assistance of the albuminoids is equally necessary to enable the fatty and saccharine foods to maintain the internal heat of the body. Of all fatty matters, whether derived from the animal or vegetable kingdom, none possesses the property of stimulating and perfecting the nutritive processes in so high a degree as cod-liver oil; it is more readily emulsified and fitted for absorption by the pancreatic secretion during intestinal digestion than any other fatty matter of which we have any knowledge.
The beneficial effects of its use have been proved in myriads of cases of confirmed consumption, and if it were used for prolonged periods by persons who are losing weight, and whose breathing capacity is too little, along with effective cultivation of the latter function, many persons would escape this disease who now succumb to it.