Theophrastus, Eudemus, and Aristoxenus are among the best-known names of these helpers, and from these we have valuable work extant. Physical geography was entrusted to Dikæarchus. All these researches were carried out in the same spirit, and with that unity of purpose that marks a school. There was apparently but one division of all the domain of science in which Aristotle did no original work, and yet his contribution to it is not to be underrated. This was the field of pure mathematics. For we know that he entrusted to his ablest pupil, Eudemus the Rhodian, the task of writing the history of what other men had done in this field. These books on the history of arithmetic, of geometry, and of astronomy (then called astrology) were well known and valued, and the modern critics declare that whatever is now known about the earlier development of mathematics was derived from this pure and rich source. Still more remarkable is it that this, the part of the edifice to which Aristotle himself did not contribute, should have been the only one that took root and flourished without any period of corruption or decay. As to Aristotle’s personal competence in this matter, I am assured by the best mathematicians that his not infrequent allusions to mathematics, by way of metaphor or illustration, show a clear and sound understanding of the subject. It is not, therefore, the vagary of an idle admirer, but the deliberate expression of a weighty judge, when we learn from him in his Discussion on Beauty—which he, being a Greek, of course seeks in form, symmetry, and proportion—that the highest and noblest examples of earthly beauty are to be found in mathematics.

Euclid was almost the contemporary of Aristotle, and so the Peripatetic Mathematics found at Alexandria a new home and a mighty development, which lasted for centuries and is not stayed to this day. But the rest of the vast system of Aristotle seems, after about two generations, to have fallen into incompetent hands. The activity of the Greek intellect passed into other channels and became again purely philosophical and ethical instead of scientific, as I shall show when I speak of the Stoic and Epicurean systems.

But there was another branch of practical science which, if not created by Aristotle, was certainly promoted by his studies in zoölogy and botany. We still regard these sciences as a necessary introduction to medicine, and we may be sure that in old days the order of such studies was not different. The distinction of being the father of rational medicine need not be added to the other crowns which adorn the great sage. Both Greeks and moderns are unanimous in awarding that honour to Hippocrates of Kos, where there was an old guild of physicians, of which he was neither the first nor the last of his name. Hence the works now known as those of Hippocrates may not all be the actual writing of one man; for as with Aristotle, so with Hippocrates, there was a school, and the pupils followed in the master’s path. But there is no doubt whatever as to the character and tone of his teaching. We find even a literary grandeur in his prose, that is not the writing of any but a great master. The famous opening of his Aphorisms is probably known to most of my hearers. But it is a puzzle to translate without dull amplification. Here is a paraphrase: “Life is brief, yet craft grows slowly; the right time is instantaneous, yet experience is treacherous, and decision burdensome.” As is the style, so is the thinking out of the problems before him. Starting from hygiene as the proper basis of medicine, he thinks those should be regarded as the earliest physicians who improved the food of primitive men by crushing grain, by cooking meat, and by selecting edible vegetables. From that time onward, there was growing up an experience of what was healthy and what the reverse. It is this experience which he seeks to systematise by careful observation and so to establish laws of hygiene, and the probable natural prophylactics or remedies afforded by air, water, and climate. He analyses with care the proper aspect for a town and decides (in the latitudes which he knew) for the eastern as the best and the western as the worst. He discusses the quality of the water supply, and lays great stress upon its altitude. He sets down careful clinical records of cases of fever—typhus, puerperal, malarious, and the like. The results of this rational treatment of disease were far-reaching and permanent. To cite to you the cloud of witnesses would be mere waste of time. But I will take one instance, closely related to the history of my great college and of medicine in Ireland.[36] The founder of the College of Physicians in Ireland under the Cromwellians and Charles II. was John Stearne, a grand-nephew of Archbishop Ussher, himself also a theologian and metaphysician. Driven out of Ireland by the stress of the Rebellion of 1641, and educated in all the medical learning of Cambridge, he returned with the Cromwellian restoration of order and became not only a Fellow of his college (along with some eminent Puritans from Harvard) but a distinguished practitioner in Dublin. By his influence was founded the Royal College of Physicians, once an adjunct to the University and ever since a great and dignified corporation, which has for many generations contributed eminent men to medical science.

But Stearne, like Hippocrates, not only practised; he wrote works on life and death; he was a theorist and a philosopher. This man, writing from the highest standpoint of Cambridge and of Dublin in the middle of the seventeenth century, tells us over and over again that the works of Hippocrates are wellnigh infallible, and are the only sure guide to medical science in his day.[37] The causes of this attitude are not far to seek. All mediæval medicine had been ruined by the admission of supernatural influences, special interventions, the action of evil spirits, the conjunction of hostile constellations, and other rubbish at which we now smile, but which men of science then deplored. The first great feature in Hippocrates is the utter ignoring of any such influences as the special causes of disease or cure. He is afraid of no ghost or goblin, he never mentions an incantation. And here is a momentous passage, which probably few of you have ever read, that expresses the mental attitude of his school. He is speaking of a class of patients affected with impotence who are venerated among the Scythians and even worshipped, each man fearing for himself, as he attributes the sickness to a special visitation of his God. “Well now I also think that these diseases are of divine ordinance and so are all the rest, but not one of them more divine or human than the rest, but all are homogeneous, and all from the gods. Yet each of them has its nature, and nothing happens without a natural cause.” He then goes on to explain the disease from the practice of too much riding, and observing that it attacks the rich more usually than the poor, because the latter do not live on horseback, he argues:

If this disease were indeed more divine in origin than the rest, it ought not to attack the rich and well bred among the Scythians, but all alike; nay rather the poor in preference, if indeed the gods delight in honour and service from men, and show them favour accordingly. For it is but natural that the rich should offer many sacrifices to the gods as they have both wealth and honour; but the poor less so, either from want of means, or want of good will toward the gods who have not favoured them, so that the poor ought to be specially subject to punishment for their transgressions or mistakes. But as I said before, this disease is heaven-sent like the rest. For everything happens according to nature.

This was the spirit that died out when the Greek world decayed, and Europe fell a victim to ignorance and superstition. Then came the heyday of miraculous images, of relics with power to cure, of pilgrimages, of intercessions, of all that mental degradation which the Mediæval Church, far from repudiating, used for its own purposes. And so the resurrection of medical science was connected with rebellion against the Church. Among every three physicians, are two atheists, was the word, and even the pious Stearne, whom I have mentioned, preaches a purely Stoic creed, and systematically ignores all the rites of his church.

Hippocrates and his school had in their day to combat similar superstitions, just as the scientific medicine of our day has to deal with Lourdes and with Christian Science. Within the last few years, we have recovered from oblivion the ruins of the temple and town of Epidauros, where the god Æsculapius had a famous shrine, and where hundreds of pilgrims assembled to seek cures for their several ailments. Their recreation was as well looked after as in any modern watering-place; the theatre was the most splendid thing of the kind in Greece, and there were porticoes, and baths, and groves to secure that comfort and idle amusement which have a great effect on health. But as we know from the ridicule of Aristophanes, corroborated by numbers of inscriptions commemorating cures, the method of these Asklepiads was far behind those of Kos; it was superstitious and not scientific. Dreams and omens, charms and ceremonial acts still stood in the way of sound hygiene and careful clinical observation. Not that I deny the occurrence of cures under such treatment. The most sceptical examination of the annals of Lourdes shows that mental influences will cure not only mental diseases, and diseases known as nervous, but even those that seemed absolutely physical. And what the Blessed Virgin does for the faithful of Lourdes may doubtless be done by the influence of more human and tangible causes. These admissions, which I make freely, will not change the opinion now held by every true man of science. It is the opinion of Hippocrates and his school, and that which he sought to enforce by his theory and his practice. The great truth that work is what exhausts the human frame, and that food supplies this waste, was laid down clearly in their practice. The equally important principle, that no organ will keep in health and vigour without exercise of its natural function and that if disused it will shrink or decay, was also clearly pronounced. They even guessed that the greatest problem of medicine (which they failed to solve) was the passage from inorganic into organic substances.

It is of course idle to say that these practitioners were not encumbered and shackled by many false guesses, many pretended discoveries, many groundless speculations of their predecessors. But as the famous oath, which every practitioner in the school of Kos took, expresses clearly the high moral aim with which even now the physician enters on his noble work, the solemn declaration that he will not abuse his influence or intimacy in any house for selfish or immoral purposes, so in their scientific aims these Greeks sought to advance human knowledge by recording honestly their observations, even by telling of their failures, and by seeking to leave behind them such clinical work as might enlighten not only successors but opponents. If we compare this truly modest and scientific attitude with that of the doctors whom Molière scourged, and whose practice is but too well known to us from the minute account of their treatment of princely or even royal patients, we shall again come to the conclusion that where the Greeks failed to teach modern Europe it was not for want of rich suggestion and splendid anticipations of modern science.

I need hardly tell you (in conclusion) that I have not only confined myself to touching the fringes of these vast subjects; I have deliberately omitted large topics such as optics, and the correction of optical delusions, which the Greeks attained by a subtle use of curves, not merely sections of a large circle, but particularly by the use of the conic section still known by its Greek name of hyperbola. I have said nothing about their astronomy, with its prediction of eclipses, its application to the calendar, and its use as the basis of scientific geography. Had I attempted to weave all these matters into the present lecture, I must have given you a kaleidoscope and not a picture. The main fact to be impressed upon you is that the great triumphs of the Greeks in art and in literature were not attained without a strict education in hard thinking and close reasoning. Plato is said to have made it the first condition of entering on a course of philosophy that the pupil should have studied geometry.

It was in accordance with that principle that in our older universities every student, though he were a specialist in classics, must show an adequate knowledge of mathematics. No man in Trinity College, Dublin, can take the degree in languages without having been taught, and having qualified in, pure mathematics, physics, and astronomy. That was the kind of education given by the Greeks. So far as we have departed from it in our education; so far as we have substituted hurry for deliberation, quantity of facts for quality of knowledge, miscellaneous information for systematic thinking, so far we have rendered modern culture impotent to rival their excellence.