When one has a hot, dry skin, a glowing red cheek, thirst, a rapid pulse, and weakness of body, with more or less dulness or disturbance of the mental faculties, we say he has fever. Constipation of the bowels, and scanty secretion from the kidneys, also commonly belong to the same condition. But of all this group of symptoms, the most constant is heat. In health, a thermometer in the armpit will mark 98.50 Fahr. Fever often runs it up to 1030, 1040, 1050, or even higher still.

Fever is met with in connection with many diseases. Inflammation of any of the great organs, brain, lungs, heart, pleura, bronchial tubes, stomach, bowels, etc., will, when active, be attended by it. And, without any inflammation, we meet with it in typhus; also with inflammatory affections secondary to the general disease, in scarlet fever, small-pox, measles, diphtheria; and with or without local inflammations, in yellow fever, in relapsing, intermittent, and remittent fevers; perhaps also sometimes without any true acute inflammation, in typhoid fever.