It is not as a physician, but as a patient, that I wish to say a word or two on fever. We cannot help now and then speaking of our enemies; and this one has been attacking me for more than twenty years; not Fréron himself has been more implacable. I ask pardon of Sydenham, who defined fever to be "an effort of nature, laboring with all its power to expel the peccant matter." We might thus define smallpox, measles, diarrhœa, vomitings, cutaneous eruptions, and twenty other diseases. But, if this physician defined ill, he practised well. He cured, because he had experience, and he knew how to wait. Boerhaave says, in his "Aphorisms": "A more frequent opposition, and an increased resistance about the capillary vessels, give an absolute idea of an acute fever." These are the words of a great master; but he sets out with acknowledging that the nature of fever is profoundly hidden. He does not tell us what that secret principle is which develops itself at regular periods in intermittent fever--what that internal poison is, which, after the lapse of a day, is renewed--where that flame is, which dies and revives at stated moments. We know fairly well that we are liable to fever after excess, or in unseasonable weather. We know that quinine, judiciously administered, will cure it. This is quite enough; the _how_ we do not know. Every animal that does not perish suddenly dies by fever. The fever seems to be the inevitable effect of the fluids that compose the blood, or that which is in the place of blood. The structure of every animal proves to natural philosophers that it must, at all times, have enjoyed a very short life. Theologians have held, as have promulgated other opinions. It is not for us to examine this question. The philosophers and physicians have been right _in sensu humano_, and the theologians, _in sensu divino_. It is said in Deuteronomy, xxviii, 22, that if the Jews do not serve the law they shall be smitten "with a consumption, and with a fever, and with an inflammation, and with an extreme burning." It is only in Deuteronomy, and in Molière's "Physician in Spite of Himself," that people have been threatened with fever. It seems impossible that fever should not be an accident natural to an animate body, in which so many fluids circulate; just as it is impossible for an animate body not to be crushed by the falling of a rock. Blood makes life; it furnishes the viscera, the limbs, the skin, the very extremities of the hairs and nails with the fluids, the humors proper for them.