An oil or fat applied by friction to the epidermis will disappear, and, as a positive gain may thus accrue, it is reasonable to suppose that not only absorption, but assimilation, also, has taken place.

Fat plays an important part in the metamorphosis of animal fluids. As was long since shown by Lehmann, a small quantity of fat is essential to the digestion of nitrogenous articles of food. Cod-liver oil, as well as other oils, when taken in the proper quantity, has the power to facilitate gastric digestion, and therefore promotes the appetite. Oil is a very important material in intestinal digestion—constitutes the molecular basis of the chyle, which consists chiefly of finely-divided fatty matter, each globule of fat being surrounded by a thin layer of albumen. The fat taken in with the food undergoes the emulsionizing process, chiefly in the small intestine, and by the aid of the pancreatic and biliary secretions. Cod-liver oil is, above all other fats, adapted to form the molecular basis of the chyle. All fats do not penetrate into the veins and lacteals with the same facility, and the presence of certain substances is necessary to the process. Fats are not crystal-loidal but colloidal substances, and have, therefore, but a feeble power of osmosis; but, notwithstanding this fact, the blood of the portal vein is much richer in fat than the blood of the arteries and systemic veins. The diffusion of fats is accomplished by the action of the bile. It was long since shown, by Wistinghausen, that in capillary tubes moistened by bile, oil will rise much higher than in tubes not so moistened, or when moistened with water or a saline solution. He also showed that oil will pass through membrane saturated with bile much more readily than through similar membrane saturated with water. It has been ascertained that, in dogs with biliary fistulae, the amount of fat in the chyle is much below the normal, and in the faeces much greater than normal (Day). Hence it must be concluded that the presence of bile is necessary to the absorption of fats, and that cod-liver oil must be peculiarly adapted to form the molecular basis of the chyle. It is for these reasons that, during a course of cod-liver oil, the body-weight is increased, the red blood-globules become more numerous, and a greater amount of fat is deposited in the tissues. It promotes the constructive metamorphosis. The important rôle performed by the oils and fats in the organism is shown by a variety of considerations. Wherever tissue-changes, physiological or pathological, are taking place, fat accumulates and enters largely into the formation of the resulting products. Newly-formed plasma contains much free fat, and all plastic exudations more than the non-plastic (Lehmann). Fat is the most abundant constituent of pus.

Food is intended ultimately for two objects: first, to build up the tissues in the growing state and to reconstruct the tissues wasted by use; second, to supply force, nervous, muscular, and digestive, to the different parts of the organism requiring it. The part performed by the fats is important as regards both objects. As already stated, they are essential to the construction of tissue; modern researches have shown that they have a necessary office in the evolution of force. The well-known experiment of Fick and Wislicenus demonstrated that, on a diet of hydrocarbons, great muscular effort can be undergone with but little destruction of muscular tissue, and without increased urea-discharge. Turkish porters, who are remarkable for their great muscular strength and endurance, live on a diet composed of fat and rice. The acrobats of Japan, who live on a similar diet, grow to an enormous size, and accomplish feats of strength and agility to which the athletes of Western nations are hardly equal.

If a muscle is made to contract under a bell-jar, an extraordinary evolution of carbonic-acid gas takes place, just as in violent muscular exercise the amount of carbonic-acid gas exhaled from the lungs is increased.

Oil and Fat Therapy

Oils and fats are used by inunction in the treatment of the scaly skin-diseases. A warm bath, if not contraindicated, may well precede the inunctions, and adeps benzoinatus, or suet, be then thoroughly rubbed in.

Inunctions of oil or fat promote constructive metamorphosis in such chronic wasting diseases as phthisis, scrofula, chronic dysentery, etc. The best oil for this purpose is cod-liver oil, but, as it stains the skin yellow and has a disagreeable odor, it is often strongly objected to. Lard or suet benzoinated can be used, or may be perfumed to the taste of the patient. The best time for practicing the inunctions is just before retiring. A warm bath should first be taken, and then from one to two ounces may be rubbed into the skin. A thick night-garment should be put on to promote absorption and to prevent injury to the bedding.

Badly-nourished infants, rickety, or scrofulous, or suffering from chronic intestinal disorders, who have a dry and scaly skin, are often materially benefited by the tepid or warm bath, followed by inunctions of lard, suet, or almond-oil. Chlorotic girls, with or without disorders of menstruation, are improved in condition by the same means. Spare women, who wish to gain flesh and roundness of form, may have their wish gratified by warm baths and inunctions of oil. The improvement which results from this practice is partly due to the general gain in bodily nutrition.

Rubeola, scarlatina, roseola, erysipelas, and other febrile diseases, are benefited by oil inunctions. These applications are grateful to the patient; they allay the burning heat of the skin, and in this way diminish restlessness and excitement. Inunctions of oil reduce the temperature, but the decline in fever-heat is in part the result of the calmative influence which these applications have over one of the chief sources of distress. Inunctions of oil have a special utility in the desquamative stage of scarlet fever. It is the author's observation that inunctions of oil are serviceable in fevers generally, when there is much heat of skin and high temperature, with restlessness. Cocoa-butter is the most elegant of these preparations for external use, but lard benzoinated is the best. In the infectious diseases, a little carbolic acid may be added to the inunction oil or fat, with the view of destroying disease-germs.

Those who experience frequent catarrhal attacks, and take cold on slight exposure, may have their susceptibility diminished by a daily application of oil to the whole surface of the body.

In many maladies, the patients experience a notable distaste for fatty food in any form. This is especially the case with scrofulous and phthisical subjects, and, as fat in some form is necessary to digestion, assimilation, and heat-producing, it is obvious that by the use of cod-liver oil an essential element of nutrition may be supplied in the best form. In cases in which there exists a condition of faulty assimilation of fats, cod-liver oil, by reason of the fact that it contains in intimate association the bile elements, is especially adapted to form the molecular basis of the chyle. In scrofula, rickets, and other disorders of the nutritive functions belonging to this group, cod-liver oil is the best agent for promoting constructive metamorphosis.

After scarlet fever in many children, especially in those with strumous diathesis, there occur discharges from the nose and ears, feeble digestion, and general emaciation. These sequelae, of scarlet fever are best removed by the internal use of cod-liver oil.

As a remedy in phthisis, cod-liver oil holds the first place, but it is not adapted to all forms and all stages of that disease. It is especially a remedy for the chronic forms of phthisis—-fibroid lung and chronic tuberculosis—and is not serviceable in caseous pneumonia and acute phthisis. It is more useful in the chronic forms of phthisis because these afford the time and opportunity to reconstruct the tissues of the body—to build up the tissues from the molecular basis of the chyle. Cod-liver oil is not well borne when there is much fever, and can not be well assimilated when the stomach has undergone the alterations which belong to acute inflammatory affections. This remedy is too often prescribed without any reference to the condition of the patient's digestive functions. The power of the stomach and intestines to digest fat is limited, and, if the quantity which can be disposed of is exceeded, the patient is incommoded. Rarely is it proper to prescribe more than a teaspoonful three times a day, and few patients can digest a tablespoonful. As the secretion of gastric juice, bile, and pancreatic juice, takes place most abundantly during the digestion of food, the time for the administration of oil in phthisical cases is after eating. When it is not well borne, the digestion and assimilation of the oil may be aided by combining it with liquor potassse, lime-water, the compound tincture of gentian, tincture of nux vomica, or strychnine, or other correctives according to the indications in individual cases. When the oil is not well digested—although stomach disorder may not have occurred—and it is seen to float on the stools, it may be combined with ether, since Bernard has demonstrated that ether increases the production of pancreatic fluid.

If continued for a sufficient length of time, cod-liver oil is of the greatest service in chronic bronchitis and emphysema. It should be given in the same way and under the same conditions as in phthisis.

Chronic rheumatism and rheumatic arthritis, maladies for the relief of which cod-liver oil was first prescribed, when occurring under bad hygienic influences in cachectic subjects, may be much relieved by this agent. In addition to the internal use of the oil, it may be applied with advantage locally to the affected joints. This combined use of the oil, systemically and by local inunction, is to be commended in the so-called rheumatic gout with deposits about the joints. On the same principle, cod-liver oil is beneficial in cases of strumous synovitis, caries, and necrosis of bone dependent on a constitutional state

It does not have, it must be admitted, any direct influence over these morbid processes; but it enters most usefully into constructive tissue-metamorphosis.

As a reconstituent, cod-liver oil is a very useful remedy in certain chronic affections of the brain and nervous system. One of the most common conditions with which we have to deal in middle and advanced life, and also one of the most important as regards the integrity of the brain, is atheroma of the arteries. This condition is represented by increased hardness of the radial pulse, the arcus senilis, irregular action of the heart, giddiness, vertigo, partial loss of vision, and failure of the memory and other intellectual faculties. Used to obviate these degenerative changes, and to prevent failure in the nutrition of the brain, we have in cod-liver oil a remedy of real value. It should be given in small quantity, and continued for a long time. As a phosphorized fat plays an important part in the structure and functions of the cerebral tissues, we may imitate the processes of Nature and administer the phosphates, the hypophosphites, or the lacto-phosphate of lime, in combination with cod-liver oil. The author has seen excellent results from such a combined use of these agents. Dr. Anstie much insists on the use of fats, especially cod-liver oil, as a part of the diet of those suffering from neuralgia, paralysis agitans, epilepsy, mercurial tremor, and chorea. Dr. Radcliffe had previously pointed out the utility of fats and oils in the same affections, and all practical physicians familiar with the subject are now pretty well agreed as to the value of this practice. The special indications for cod-liver oil in these affections are faulty assimilation and a low condition of the nutritive functions. Fats and oils are, of course, contra-indicated in these nervous disorders when they occur in plethoric and overfed subjects, but such a state of things is exceptional.

In diseases of the shin of strumous origin, cod-liver oil is, as Dr. Tilbury Fox remarks, "our sheet-anchor." Among these diseases are lupus, ecthyma, psoriasis, scleroderma, etc. The constitutional state requiring cod-liver oil is a lowered condition of the assimilative functions dependent on the strumous cachexia. The local use of the oil is certainly advantageous in these cases. Dr. Hughes Bennett strongly recommends the free application of the oil to favus and eczema im-petiginodes.

The condition of debility and faulty assimilation which results from the prolonged treatment of syphilis with mercury and iodine is frequently remarkably improved by cod-liver oil. The syphilodermata, when occurring in cachectic subjects, are benefited by a persistent use of the same remedy. With the internal use of the oil may be conjoined inunctions. These are especially beneficial in the squamae of syphilitic origin.