Among the labors of the present generation, none perhaps have already more far-reaching results, none hold out more promise of fruit in the future, than those which bear on the influence of the nervous system over the circulation of the blood and over nutrition. The knowledge we are gradually acquiring of the subtile nervous bonds which bind together the unconscious members of the animal commonwealth, which make each part or organ at once the slave and guardian of every other, and which with cords of nervous sympathy draw each moiety of the body to work for the good of all, is putting a new aspect on physiology, and throwing many a gleam of light into the very darkest regions of the science. The words "inflammation" and "fever," bandied about of old as mystery-words, sounding much but signifying little—shuttlecocks tossed to and fro from one school of doctrinaire pathologists to another—now at last, through the labors of modern physiology, seem in a fair way of being understood. That understanding, when it is complete, will have been gained step by step through experiments on living animals, one of the first of which was Claude Bernard's research on vaso-motor nerves.[1]
There still remains the question, What good does physiology bring to mankind? Of the value of physiology as a not insignificant segment of the circle of universal knowledge, nothing need be said; where saying aught is necessary, it would be useless. Nor need much be said concerning the practical value of physiology as a basis for the conduct of life. So long as men refuse to learn or to listen to physiology in order that they may the better use their bodies, it would be hopeless and useless to talk of the day when they may come to it for instruction how to form their minds and mould their natures. It will be enough for my present purpose to point out briefly the relations of physiology to the practical art of medicine.
These are twofold. In the first place, the medical profession is largely indebted to physiology on account of special discoveries and particular experimental researches. If we regard the profession simply as a body of men who possess or should possess a remedy for every disease, this may seem an exaggerated statement. Many of the remedies in use or in vogue at the present day have been discovered by chance, borrowed from ignorant savages, or lighted on by blind trials. Physiology can lay no claim to the introduction of opium or quinine. Where specific remedies have been suggested by physiologi-
- ↑ The great importance of the vaso-motor system justly led Mr. Huxley to introduce into his "Elementary Lessons in Physiology" Bernard's fundamental experiment with some such words as "a rabbit may be made to blush artificially by dividing the sympathetic nerve." A writer, apparently biased by the memories of his own boyhood, has accused Mr. Huxley of thereby dangerously inciting boys and girls to cruelty, as if the division of the sympathetic nerve were the sort of thing a school-boy might do with a pocket-knife and a bit of string. Is it any use to enlighten the malevolent ignorance of such minds by telling them that many physiological experiments require such skill and care as make ordinary surgical operations seem rough and easy proceedings?
