Salerno represents an especially important chapter in the history of Medieval Medicine. As we shall see, the teachers at the great medical school there set themselves in strenuous opposition to the Arabian tendency to polypharmacy, by which the Oriental mind had seriously hurt medicine, and what is still more to the credit of these Salernitan teachers, they developed surgery far beyond anything that the Arabs had attempted. Indeed, surgery in the later centuries of Arabian influence had been distinctly neglected, but enjoyed a great revival at Salerno. Besides, the Salernitan physicians used all the natural methods of cure, air, water, exercise, and diet, very successfully. If any other proof were needed that Arabian influence was not prominent at Salerno, surely it would be found in the fact that women physicians enjoyed so many privileges there. This is so entirely opposed to Mohammedan ways as to be quite convincing as a demonstration of the absence of Arabian influence.

From Salerno, the tradition of medicine and surgery spread to Bologna early in the thirteenth century, and thence to the other universities of Italy and to France. Montpellier represented an independent focus of modern progress in medicine, partly due to close relationship with the Moors in Spain and the Greek influences they carried with them from Asia Minor, but not a little of it consequent upon the remnants of the older Greek culture, still not entirely dead even in the thirteenth century, because Marseilles, not far away, had been a Greek colony originally, and still retained living Greek influence, and wherever Greek got a chance to exercise its stimulant incentive modern scientific medicine began to develop.

France owed most of her development in medicine and surgery at the end of the Middle Ages to the stream of influence that flowed out of Italian universities. Such men as Lanfranc, who was an Italian born but exiled; Mondeville, who studied in Italy; and Guy de Chauliac, who has so freely acknowledged his obligation to Italian teachers, were the capital sources of medical and surgical teaching in France in the later Middle Ages.

It is thus easy to see how the two periods of historical import in medicine at the beginning and end of the Middle Ages may be placed in their intimate relation to Greek influences. At the beginning, Greek medicine was not yet dead in Asia Minor, and it influenced the Arabs. When the revival came, it made itself first felt in the portions of Southern Italy and Southern France where Greek influence had been strongest and still persisted. Fortunately for us, the great Renaissance printers and scholars, themselves touched by the Greek spirit of their time, put the books of the writers of these two periods into enduring printed form, and in more recent years many reprints of them have been issued. These volumes make it possible for us to understand just how thoroughly these colleagues of the Middle Ages faced their problems, and solved them with a practical genius that deserves the immortality that their works have been given.

The history of medicine and surgery during the Middle Ages has been greatly obscured by the assumption that at this time scientific medicine and surgery could scarcely have developed because men were lacking in the true spirit of science. The distinction between modern and medieval education is often said to be that the old-time universities sought to increase knowledge by deduction, while the modern universities depend on induction. Inductive science is often said to be the invention of the Renaissance period, and to have had practically no existence during the Middle Ages. The medieval scholars are commonly declared to have preferred to appeal to authority, while modern investigators turn to experience. Respect for authority is often said to have gone so far in the Middle Ages that no one ventured practically to assert anything unless he could find some authority for it. On the other hand, if there was any acknowledged authority, say Aristotle or Galen, men so hesitated to contradict him that they usually followed one another like sheep, quoting their favourite author and swearing by the authority of their chosen master. Indeed, many modern writers have not hesitated to express the greatest possible wonder that the men of the Middle Ages did not think more for themselves, and above all did not trust to their own observation, rather than constantly rest under the shadow of authority.

Above all, it is often asked why there was no nature study in the Middle Ages—that is, why men did not look around them and see the beauties and the wonders of the world and of nature, and becoming interested in them, endeavour to learn as much as possible about them. Anyone who thinks that there was no nature study in the Middle Ages, however, is quite ignorant of the books of the Middle Ages. Dante, for instance, is full of the knowledge of nature. What he knows about the ants, and the bees, and many other insects; about the flowers, and the birds, and the habits of animals; about the phosphorescence at sea and the cloud effects, and nearly everything else in the world of nature around him, adds greatly to the interest of his poems. He uses all these details of information as figures in his “Divine Comedy,” not in order to display his erudition, but to bring home his meaning with striking concreteness by the metaphors which he employs. There is probably no poet in the modern time who knows more about the science of his time than Dante, or uses it to better advantage.

It is sometimes thought that the medieval scholars did not consider that experience and observation were of any value in the search for truth, and that therefore there could have been no development of science. In an article on “Science at the Medieval Universities”² I made a series of quotations from the two great scientific scholars of the thirteenth century, Albertus Magnus and Roger Bacon, with regard to the question of the relative value of authority and observation in all that relates to physical science. Stronger expressions in commendation of observation and experiment as the only real sources of knowledge in such matters could scarcely be found in any modern scientist. In Albert’s tenth book of his “Summa,” in which he catalogues and describes all the trees, plants, and herbs known in his time, he declares: “All that is here set down is the result of our own experience, or has been borrowed from authors whom we know to have written what their personal experience has confirmed; for in these matters experience alone can be of certainty.” In his impressive Latin phrase, experimentum solum certificat in talibus. With regard to the study of nature in general he was quite emphatic. He was a theologian as well as a scientist, yet in his treatise on “The Heavens and the Earth,” he declared that: “In studying nature we have not to inquire how God the Creator may, as He freely wills, use His creatures to work miracles, and thereby show forth His power. We have rather to inquire what nature with its immanent causes can naturally bring to pass.”

Roger Bacon, the recent celebration of whose seven hundredth anniversary has made him ever so much better known than before, furnishes a number of quotations on this subject. One of them is so strong that it will serve our purpose completely. In praising the work done by Petrus, one of his disciples whom we have come to know as Peregrinus, Bacon could scarcely say enough in praise of the thoroughly scientific temper, in our fullest sense of the term, of Peregrinus’s mind. Peregrinus wrote a letter on magnetism, which is really a monograph on the subject, and it is mainly with regard to this that Roger Bacon has words of praise. He says: “I know of only one person who deserves praise for his work in experimental philosophy, for he does not care for the discourses of men and their wordy warfare, but quietly and diligently pursues the works of wisdom. Therefore, what others grope after blindly, as bats in the evening twilight, this man contemplates in their brilliancy, because he is a master of experiment. Hence, he knows all of natural science, whether pertaining to medicine and alchemy, or to matters celestial or terrestrial. He has worked diligently in the smelting of ores, as also in the working of minerals; he is thoroughly acquainted with all sorts of arms and implements used in military service and in hunting, besides which he is skilled in agriculture and in the measurement of lands. It is impossible to write a useful or correct treatise in experimental philosophy without mentioning this man’s name. Moreover, he pursues knowledge for its own sake; for if he wished to obtain royal favour, he could easily find sovereigns who would honour and enrich him.”

Roger Bacon actually wanted the Pope to forbid the study of Aristotle because his works were leading men astray from the true study of science—his authority being looked upon as so great that men did not think for themselves, but accepted his assertions. Smaller men are always prone to act thus at any period in the world’s history, and we undoubtedly in our time have a very large number who do not think for themselves, but swear on the word of some master or other, and very seldom so adequate a master as Aristotle.

Bacon insisted that the four great grounds of human ignorance are: “First, trust in inadequate authority; second, that force of custom which leads men to accept without properly questioning what has been accepted before their time; third, the placing of confidence in the assertions of the inexperienced; and fourth, the hiding of one’s own ignorance behind the parade of superficial knowledge, so that we are afraid to say, ‘I do not know.’” Prof. Henry Morley suggested that: “No part of that ground has yet been cut away from beneath the feet of students, although six centuries have passed. We still make sheepwalks of second, third, and fourth, and fifth hand references to authority; still we are the slaves of habit, still we are found following too frequently the untaught crowd, still we flinch from the righteous and wholesome phrase, ‘I do not know,’ and acquiesce actively in the opinion of others that we know what we appear to know.”

It used to be the custom to make little of the medieval scientists because of their reverence for Aristotle. Generations who knew little about Aristotle, especially those of the seventeenth and eighteenth centuries, were inclined to despise preceding generations who had thought so much of him. We have come to know more about Aristotle in our own time, however, and as a consequence have learned to appreciate better medieval respect for him. Very probably at the present moment there would be almost unanimous agreement of scholars in the opinion that Aristotle’s was the greatest mind humanity has ever had. This is true not only because of his profound intellectual penetration, but above all because of the comprehensiveness of his intelligence. For depth and breadth of mental view on a multiplicity of subjects, Aristotle has never been excelled and has but very few rivals. The admiration of the Middle Ages for him, instead of being derogatory in any way to the judgment of the men of the time, or indicating any lack of critical appreciation, rather furnishes good reasons for high estimation of both these intellectual modes of the medieval mind. Proper appreciation of what is best is a much more difficult task than condemnation of what is less worthy of regard. It is the difference between constructive and destructive criticism. Medieval appreciation of Aristotle, then, constitutes rather a good reason for admiration of them than for depreciation of their critical faculty; and yet they never carried respect and reverence to unthinking worship, much less slavish adoration. Albertus Magnus, for instance, said: “Whoever believes that Aristotle was a God must also believe that he never erred; but if we believe that Aristotle was a man, then doubtless he was liable to err just as we are.” We have a number of direct contradictions of Aristotle from Albert. A well-known one is that with regard to Aristotle’s assertion that lunar rainbows appeared only twice in fifty years. Albert declared that he himself had seen two in a single year.

Galen, after Aristotle, was the author oftenest quoted in the Middle Ages, and most revered. Anyone who wants to understand this medieval reverence needs only to read Galen. There has probably never been a greater clinical observer in all the world than this Greek from Pergamos, whose works were destined to have so much influence for a millennium and a half after his time. How well he deserved this prestige only a careful study of his writings will reveal. It is simply marvellous what he had seen and writes about. Anatomy, physiology, pathological anatomy, diagnosis, therapeutics—all these were magnificently developed under his hands, and he has left a record of accurate and detailed observation. There are many absurdities easily to be seen in his writings now, but no one has yet written on medicine in any large way who has avoided absurdities, nor can anyone hope to, until we know much more of the medical sciences than at present. The therapeutics of any generation is always absurd to the second succeeding generation, it has been said. Those in the modern time who know their Galen best have almost as much admiration for him, in spite of all our advance in the knowledge of medicine, as the medieval people had. No wonder, seeing the depth and breadth of his knowledge, that he was thought so much of, and that men hesitated to contravene anything that he said.

Even in the authorities to which they turned with so much confidence, the medieval physicians are admirable. If man must depend on authority, then he could not have better than they had. As with regard to this, so in all other matters relating to the Middle Ages, the ordinarily accepted notions prove to have been founded on ignorance of actual details, and misconceptions as to the true significance of their point of view. To have contempt give way to admiration, we need only to know the realities even in such meagre details as can be given in a short manual of this kind. The thousand years of the Middle Ages are now seen to have been full of interesting and successful efforts in every mode of human activity, and medicine and surgery shared in this to the full.