The rise of the body temperature is the pathognomonic sign of fever. It is not, however, the only symptom which constitutes it. The well-known pathological condition known as fever is manifested by a group of symptoms, one or more of which may be more or less marked or may be even entirely absent. The rise of temperature is generally preceded by chill or rigor. The person has the sensation of general chilliness; he shivers, and feels as if cold water were running down his back; the skin has the appearance of goose skin, and is often bluish in colour; the face looks pinched, the eyeballs are sunken, respiration is more frequent and the pulse quickened. The patient feels nauseated, depressed, miserable in mind and body, and attempts to obtain warmth by curling himself up into warm bedding or clothes. Rise of temperature follows, and is accompanied in typical cases with restlessness of the body and limbs, headache, dulness and mental apathy, extreme sensibility to light and noise, a feeling of great fatigue, rapidly increasing muscular weakness, drowsiness or sleeplessness, with illusions, hallucinations and delirium, wasting both of the muscles and of the fat of the body, an arrest of the digestive functions, and an inability to digest solid food, great thirst, dry mouth, dirty tongue, a dry burning skin, scanty excretion of urine, and often constipation.

This collection of symptoms shows a profound disturbance of all the organs of the body. Whether the increased heat is the cause of these symptoms and organic disturbances, or whether the increased temperature is one of the effects of a specific poison acting on the sympathetic nervous system, are points which are still undecided by pathologists. The question of importance to us, in considering the treatment of fever from the dietetic point of view, is not theoretical, but how, practically, to prevent by proper diet the extravagant tissue waste which is going on during the fever process, and so to maintain and build up the strength of the patient, that when the fever has passed, convalescence may proceed uninterruptedly towards recovery.