seems so homogeneous; they can explain to you how this nerve is the organ of sensation, and that of motion, and how a third marshalls in one army the various corps that perform this or that function—they can unravel a multitude of such mysteries with as much (or as little) real knowledge, and yet you may search in vain for one who can demonstrate the nature of diseases, and still less their cure. There is no formula by which you may cure consumption, or pneumonia, or a specific fever, or any other disease under the sun. The student or young physician who has felt so sure of himself while he was expounding the mysteries of physiology, stands silent and abashed before the rationale of the simplest therapeutic act; and so little is he sure of the remedies he should choose that after he has expended all his laboratory science, and even all his skill derived from experience upon an apparently simple question, he is obliged to confess that vital problems are too deep for him to understand, and that his highest real achievement in therapeutics must be the employment of not the most certain remedies, but the best authenticated by reason and experience, and so feel entitled to hope for, but never to be absolutely sure of, the desired result.
An eminent man of science has emphasized his condemnation of the popular notions upon this subject by saying that "An explanation is never given by science: the whole of science is description" (Prof. Karl Pearson, Fortnightly Review, November, 1895, p. 675). The interpretation of the things described may, and indeed must, vary more or less with the mental nature and the competency of the interpreter. And so the less of one's self one weaves into the descriptions he gives of diseases and of their treatment, the more faithfully will he represent the truth of nature, and the nearer will he approach a likeness to those great physicians who, from Hippocrates to our own day, have "held the mirror up to nature."
What has been said of one of the greatest thinkers of modern times, Goëthe, may serve as the pattern of all natural philosophers, and especially of rational physicians: "He possessed the patient observation, the reliance on careful experiment, the aversion to hasty theorizing, the instinct for so co-ordinating numerous facts into a general law which collectively mark the highest scientific genius" (John Owen, The Five Great Sceptical Dramas, p. 220).
But clinical, experimental, and, indeed, every form of observation is intended not only to preserve a photographic picture of bare facts, but also to produce a special grouping and sequence of facts that will
