The febrile state induces serious changes in the constitution of solids and liquids. The interstitial fat disappears from the tissues, which become soft and watery. The muscles grow flabby and pale, and decline in contractile energy. Digestion is feeble, or suspended or abnormal, and the food supplied is either rejected or enters the blood in an imperfectly-prepared state. The blood suffers material alterations; the red corpuscles diminish in number; the fibrin increases, and the products of imperfect tissue-metamorphosis accumulate. The urine is usually scanty and high-colored, and loaded with uric acid and urates. The chlorides more or less diminish in or disappear from the urine, but accumulate in the inflamed tissues. The excretion of phosphates is increased. In the tissues, the seat of organic alterations, rapid but imperfect metamorphosis ensues, and on the one side pathological materials crowd the interstices in the anatomical elements, and on the other the products of waste struggle for elimination. Avoiding further speculation as to the fever-process, it will suffice to state that an enormous increase of the urea-discharge takes place, and that the organs and tissues of the body undergo a granular disintegration, which has been designated "parenchymatous degeneration"; or, as it may be stated, the increased temperature of fever represents an enormous consumption of the nitrogenous elements. The higher the range of temperature, as a rule, the more extensive the parenchymatous degeneration.

In fevers and inflammations not of the digestive tract, the most useful aliments are milk and beef-juice. These should be given at intervals determined by their rate of digestibility, usually about every three hours. Fresh milk only should be used, and, if the stomach be irritable, it may be diluted with one half to one fourth of lime-water. It has been conclusively demonstrated that fresh milk is the most suitable aliment in typhoid, and it may be depended on wholly (Johnson). It is equally applicable as the aliment in scarlatina, partly as a nutrient, and partly as a diuretic, for in this disease one of the chief dangers is from arrest of the urinary secretion.

The author is convinced that beef-tea and beef-essence are too exclusively used in the treatment of the fevers and inflammatory diseases. As an aliment, beef-tea is comparatively inferior, and is also difficult of digestion. It is not unusual to see, in cases of typhoid, the beef-tea floating on the peculiar dejections of this disease. It ought, therefore, never to be used as the exclusive aliment in typhoid cases. Another fallacy of a very dangerous kind is current in domestic practice, viz., the belief that beef-tea, which gelatinizes on cooling, is especially rich in nutritive elements. Such beef-tea consists chiefly of gelatin, which has very little value as a nutrient.