The enumeration of his writings by different authors varies very much. Renouard, who seems to have studied the subject very carefully, gives the following as appearing to him to be the authentic list of writings of Hippocrates the Second,—i.e., the Great: The Prognostic, the Aphorisms, the first and third books of Epidemics, that on Regimen in Acute Disease, that on Airs, Waters, and Places, that on Articulations and Luxations, that on Fractures, and the Mochlic, or the treatise on instruments and reduction. This list does not comprise the fourth part of the entire Hippocratic collection, but its authenticity appears to be undoubted, and it suffices, as Renouard says, to justify the enthusiasm of his contemporaries and the admiration of posterity. Later, joined with the writings of Pythagoras, Plato, Aristotle, and others, they constituted the so-called Hippocratic collection, which was a definite part of the great libraries of Alexandria and Pergamos, and formed the most ancient authentic monument of medical science.
Respect for the bodies of the dead was a religious observance in all Greece, and prevented the dissection of the human body. Consequently the knowledge of anatomy possessed by Hippocrates must have been meagre. Nevertheless, he described lesions, like wounds of the head, of the heart, the glands, the nature of bones, etc. It being impossible to establish a physiology without an anatomical basis, it is not strange that we find but little physiology in the Hippocratic writings, and that this little is very crude and incorrect. Arteries and veins were confounded, and nerves, tendons, ligaments, and membranes were represented as analogous or interchangeable tissues. The physiologists of those days abandoned themselves to transcendental speculation concerning the nature and principles of life, which some placed in moisture, others in fire, etc. Speculation, thus run wild, prevented such accurate observation as might have greatly enhanced the progress of physiological knowledge.
Hippocrates wrote at least three treatises concerning hygiene: The first, on Airs, Waters, and Places; the second, on Regimen; the third, on Salubrious Diet,—practically an abridgement of the preceding, in which he recommends the habit of taking one or two vomits systematically every month. The classification of diseases into internal or medical, and external or surgical, is not modern, but is due to Hippocrates; neither is it philosophic, although it is very convenient.
With so little knowledge of physiology and pathology as the ancients had, it is not strange that they ascribed undue importance to external appearance; in other words, to what has been termed semeiotics, which occupies a very considerable place in the medical treatises of the Asclep-iadæ. Indeed, the writings on this subject constitute more than one-eighth part of the entire Hippocratic collection. To prognosis, also, Hippocrates ascribed very great importance, saying that "The best physician is the one who is able to establish a prognosis, penetrating and exposing first of all, at the bedside, the present, the past, and the future of his patients, and adding what they omit in their statements. He gains their confidence, and being convinced of his superiority of knowledge they do not hesitate to commit themselves entirely into his hands. He can treat, also, so much better their present condition in proportion as he shall be able from it to foresee the future," etc.
To the careful scrutiny of facial appearances, the position, and other body-marks about the patient he attributed very great importance; in fact, so positive was he about these matters that he embodied the principal rules of semeiotics into aphorisms, to which, however, there came later so many exceptions that they lost much of their value. From certain passages in his book on Prediction, and from the book on Treatment, which is a part of the Hippocratic collection, it appears that it was the custom then of physicians to announce the probable issue of the disease upon the first or second visit,—a custom which still prevails in China and in Turkey, It gave the medical man the dignity of an oracle when right, but left him in a very awkward position when wrong.
To Hippocrates we are indebted for the classification of sporadic, epidemic, and endemic forms, as well as for the division of disease into acute and chronic. Hippocrates wrote extensively on internal disease, including some particular forms of it, such as epilepsy, which was called the sacred disease; also fragments on diseases of girls, relating particularly to hysteria; also a book on the nature of woman, an extensive treatise on diseases of women, and a monograph on sterility. That Hippocrates was a remarkably close observer of disease as it appeared to him his books amply prove; in fact, they almost make one think that close observation is one of the lost arts, being only open to the objection that too much weight was attached to insignificant external appearances, speculation on which detracted from consideration of the serious feature of the case. His therapeutics, considering the crude information of the time, was a vast improvement on that which had preceded, and really entitled him to his title of "Great Physician."
Of external diseases and their surgical therapeutics he wrote fully: on The Laboratory of the Surgeon, dealing with dressings, bandaging, and operating; on Fractures; and on Articulations and Dislocations; showing much more anatomical knowledge than was possessed by his contemporaries. The Mochlic was an abridgment of former treatises; in Wounds of the Head he formulated the dictum concerning the possible danger of trifling wounds and the possible recovery from those most serious, so often ascribed to Sir Astlev Cooper. Other monographs, also, he wrote, on Diseases of the Eye, on Fistula, and on Hoemorrhoids. He described only a small number of operations, however, and all the Hippocratic writings on surgery would make but a very incomplete treatise as compared with those that belong to the next historical epoch; all of which we have to ascribe—in the main—to prejudice against dissection and ignorance of anatomy.
From the earliest times physicians and writers occupied themselves largely with obstetrics, as was most natural. The Hippocratic collection includes monographs on Generation; the Nature of the Infant; the Seventh Month of Pregnancy; the Eighth Month of Pregnancy; on Accouchement; Superfoetation; on Dentition; on Diseases of Women; on Extraction of the Dead Foetus. The treatise on superfcetation concerned itself mainly with obstetrics.
On epidemics Hippocrates writes extensively, showing that he had studied them carefully. He was among the first to connect meteorological phenomena with those of disease during given seasons of the year, expressing the hope that by the study of storms it would be possible to foresee the advent of the latter, and prepare for them. Seven books of the Hippocratic collection bear the title of Epidemics, although only two of them are exclusively devoted to this subject. In these books were contained a long list of clinical observations relating to various diseases. They constituted really a clinical study of disease.
The collection of Hippocrates's Aphorisms fills seven of the books; no medical work of antiquity can compare with these. Physicians and philosophers of many centuries have professed for them the same veneration as the Pythagoreans manifested for their golden verses. They were considered the crowning glory of the collection. Even within a short time past the Faculty of Paris required aspirants for the medical degree to insert a certain number of these in their theses, and only the political revolution of France served to cause a discontinuance of this custom. These aphorisms formed, says Littré, "a succession of propositions in juxtaposition, but not united." It has always been and always will be disadvantageous for a work to be written in that style, since such aphorisms lose all their general significance; and that which seems isolated in itself becomes more so when introduced into modern science, with which it has but little practical relationship. But not so if the mind conceive of the ideas which prevailed when these aphorisms were written; in this light, when they seem most disjoined they are most related to a common doctrine by which they are united, and in this view they no longer appear as detached sentences.