generalization of heat and cold, dry and moist division of diseases and constitutions. The same observation holds true in regard to the old maxim that diseases were cured by their opposites. This opinion was advanced by Hippocrates, and rendered into Latin by Galen thus: Contraria contrariis curantur. It was advanced by Hippocrates merely as a working hypothesis, or guide in selecting remedies, not as a universal procedure; it is still authority, however, in theory and practice. Its opposite, similia similibus curantur, is as frequently operative in practice, since Nature pays little heed to theories in her reaction against morbificants. As a general proposition, both doctrines are demonstrably true; but they have lost dignity as a law of nature, for in practice there are many exceptions to them. For example: In cases of simple diarrhoea, it is a good rule to give a medicine with tonic or astringent properties; but if the cause be found to be an indigestion, or a chill, or a toxæmia, the indications of treatment would be reversed and loosening medicine, or medicine with corrective properties, neither for nor against the malady, be administered. If, on the contrary, constipation be the malady under observation, the indication would call for loosening drugs, or drugs that increase the peristalsis of the alimentary tract. In such a case the contrary principle is operative. But, again, there are conditions where a relaxing medicine would be contra-indicated, when it would not be wise to excite an action of the bowels, as in certain states of typhoid fever, or on the eve of an exanthemata, or an attack of zymotic diseases, as measles, scarlet fever, etc., when the bowels should not be disturbed until after the eruption is assured. Had either of these illustrious men been in possession of the light which recent discoveries have shed on the specific nature of certain maladies and their toxic causation, their maxims would have been worded differently. Infection and toxæmia were effects well known to the Greek physician; but the precise nature of those morbific poisons was unknown to them and to their followers down to a very recent period, when the microscope came into use in diagnosis. Finally, Galen was no servile imitator of the Father of Medicine. He was Hippocrates' foremost disciple and most distinguished descendant, and also his most illuminated interpreter. His genius added lustre to the character of his master, which enabled the generations that have followed the better to understand him. M. Le Clerc, has given us the best account of Galen, which we translate as follows: Galen has been held in the highest esteem, in ancient as well as modern times. Athenée, who was contemporary with him, remarked the consideration. in which he held him, introducing him to the banquet (Festin) of philosophers as one of the learned of the banquet; and he not only gave him credit as an instructor, by the great number of his writings, but added that Galen was not excelled in clearness of elocution. Eusebius, who lived about a century later than Galen, said that the veneration in which that physician was held was carried so far as to cause him to be regarded as a god by many, who rendered him religious homage. Trallian gave him the title of very divine (très-divin). Oribasius, who survived Eusebius, and who was himself a physician, acknowledged the favor in which he regarded Galen, by the extracts which he made from his books, and by the praises he gave him. . . . Artius and Paulus Aginetius closely copied Galen. Avicenna and Averrhoës and other Arabian physicians placed Galen among the highest, and acknowledged their indebtedness to him for his teachings.' We pass over a part of the favorable testimony of the moderns-that is to say, of those who have written since a century or two, and the great number of his commentators, because it is a fact well known and generally admitted. 'Histoire de la Médecine, troisième partie, livre iii., p. 667. FOURTH: THE MEDIEVAL PERIOD THE CHAPTER IV IMPOSTURE MEDICINE Part I.-The Dark Ages HERE is much discrepancy of opinion among historians as to the approximate period of the so-called Dark Ages, when they began and when they closed. Hallam rather arbitrarily fixes (and no historian has a better right) their beginning at Rome in the sixth century; but then there was a long period of after-glow, when the light of Greece went out in the West-a period of twilight of several centuries before absolute darkness finally set in,-and the capture of Alexandria by the Saracens, early in the seventh century (A. D. 638). Interest in learning and things of time and sense began to wane in Galen's day at Rome, in the second century. The climax of darkness was reached in Germany in the tenth century, and in France a little earlier. Hallam says that France and Germany began to improve, to awaken, at the advent of Charlemagne-the tenth century,-but the improvement was slow. In England the darkest period did not reach its climax before the thirteenth, nor end until |