Practically all infectious diseases are ushered in with fever. Sometimes the fever continues throughout the course of the disease until convalescence begins. On the other hand, fever, as a rule, means infection of some kind. It seems wise, therefore, to begin this discussion with a more or less detailed treatment of dietetics in fevers in general.

The practical advantage of this method of treatment will be evident as we proceed. When once the fundamental principle of dietetics in fevers in general is thoroughly understood, the application of these general principles to numerous febrile conditions found in the various infectious diseases will be only a matter of detail and will be simple.

The initial fast which should be instituted in all fever cases must be of varied duration according to circumstances. If the patient is well nourished before the onset of the fever, and if the illness is of a character which will probably not be of long duration, a fast of three days may not be too long. If, on the other hand, the patient is in a state of low nutrition, and if the illness is of a character where several weeks of duration may be expected, it is important to shorten the fasting period to a much lower limit, perhaps not over twenty-four hours. In many cases of beginning fever there is some nausea, in most cases a decided disinclination to eat. These are Nature's indices as to the rational course to take.

Water should be freely used during all fevers, but its use during the fasting period should be especially copious for several reasons. In the first place, the patient is certain to experience considerable thirst. This is nature's indication of the rational treatment. The action of water in the system at this time is easily understood in the light of the preceding chapters. It is the most effective agent in the control of body temperature. It is the most effective agent in elimination of waste materials, whether these waste materials have accumulated in the intestinal tract or in the blood. If in the intestinal tract, the water facilitates free bowel movements; if in the blood, the water facilitates kidney activity and the waste materials are readily carried away. While pure water is probably the best drink that can be presented to the patient during this and the subsequent period, many variations may be instituted; such acid drinks as lemonade and orangeade may be freely given; weak tea and iced coffee may also serve as an agreeable change. One should never forget in this connection that the citrous drinks serve as stimulants both to kidney action and to skin action. In this stage of the case it is not unlikely that this stimulation is a much-desired effect to produce. Furthermore, tea and coffee act as stimulants to the nervous system. Such stimulation may be desirable, or the reverse. The dietitian will be governed accordingly.

Vomiting and nausea, whenever they appear as initial symptoms of an infectious disease, should be considered as an indication to be followed, and the fasting period should be continued so long as the vomiting and nausea remain.

The first food given to the fever patient should be liquid. Unless there are very good reasons to the contrary - as, for example, personal idiosyncrasy against it - this first liquid food should be milk. The almost universal choice of milk as the staple liquid food in the early stages of fevers is due to the fact that, as a rule, it is easily digested, non-irritant to the stomach, does not yield an appreciable bulk of unabsorbed material, and is rarely subjected to putrefactive changes within the intestines. Occasionally we find a patient who does not digest unmodified milk easily. In such cases a modification of the milk may readily be made. One of the best agents for this purpose when the milk is to be taken into the stomach is barley water, which may be added to the milk before it is taken. When thus treated the casein does not coagulate into curds in the stomach. Another modification of the milk is the addition of limewater to the extent of two ounces to a pint. This addition of limewater greatly facilitates the digestion of the casein. Sometimes the dilution of the milk with plain water is a sufficient modification. The addition of some flavoring material may make the milk more palatable, though it would not modify its digestion.

Beef juices or broths may be used freely and serve to break: the monotony of the milk diet. (For recipes, see Appendix I.) Sometimes milk can be added to the broth, in which case the nourishment may be represented mostly by the milk - the broth furnishing the flavor.

Semi-solid foods may be introduced in most fever cases after the first few days. The indication for the introduction of semi-solids into the diet should be an evidence of the complete digestion and absorption of the liquid diet previously given, and an appetite on the part of the patient for something more substantial. The semisolid foods are those which readily become liquefied either in the mouth or stomach as the result of mastication or rise of temperature or through the solvent action of saliva or gastric juice. Among these semi-solid foods may be named ice cream, fruit jelly, meat jelly, junket, custard, souffle, and gruel. In all these, complete quick action in the mouth or stomach is insured. In the preparation of gruels cereals are used.

In order to make the cereals easy of mastication and of complete liquefaction after mastication, the greatest care should be used in their preparation. Hours of boiling may be necessary to reduce rice, barley, oatmeal, or other cereal meal or flour to the required condition. Cornstarch jellies, tapioca, and sago may also be so prepared as to belong properly to this class of semi-solid foods. The transition from liquid to semi-solid foods should be a gradual one, and these should be introduced into the dietary in such a way as to provide variety. As the patient enters upon his convalescence there should be an equally gradual transition from semi-solid to solid foods.

Solid foods may be understood to include any foods in the dietary which require to be ground by the teeth in order to reduce them to a semi-solid condition. In the choice of solid foods for a convalescent patient, one has usually a wide range and may freely consult the likes and dislikes of his patient, not losing sight, however, of the importance of serving only such foods as represent considerable nourishment or such as have a laxative effect on the bowels. Meats, vegetables, fruits, and cereals may be freely used; they should always be served in small portions and prepared in such a way as to be easily digested. All attendants upon the sick should emphasize the importance of a very thorough mastication of the food. A convalescent patient cannot plead lack of time for that process.

Febrile albuminuria sometimes appears late in a fever case as a complication. Whenever this complication arises the diet should be at once modified and the patient put upon a strictly liquid diet, principally milk, until the symptom disappears.