This Humoral Pathology assumed the existence of four humours in the body, viz., blood, melancholy, choler, and phlegm. Blood was supposed to be formed by the liver, melancholy by the spleen, choler by the gall-bladder, and phlegm by the stomach. The temperament of each individual was termed sanguine, melancholy, choleric, or phlegmatic, according to the humour naturally predominant in his constitution, and one fluid prevailing with abnormal excess over the others gave rise to morbid conditions. The faculty still held to the doctrine of "signatures," as it was called, as the basis of therapeutics; which doctrine assumed certain remedies to be potent in certain diseases, because there was some external resemblance or fanciful connection between the two. Thus, scarlet bed-curtains were a cure for scarlet fever, measles, or any disease with a red eruption on the skin, and the grandfather of Maria Theresa died of small pox, wrapped by order of his physicians in twenty yards of scarlet broadcloth! The yellow powder turmeric was a remedy for jaundice, the lung of the long-winded fox a cure for asthma and shortness of breath; the heart of a nightingale was prescribed for loss of memory; the royal touch was a specific for scrofula or king's evil; and we find John Brown, chirurgeon in ordinary to Charles II., writing a treatise on the "Royal gift of healing strumæs by imposition of hands," with a description of the proper and efficacious manner of conducting the ceremony. This delusion actually held its ground until the eighteenth century, when the great Dr. Johnson was touched by Queen Anne.

As late as 1623, Sir Kenelm Digby, the Admirable Crichton of his time, produced a sympathetic powder whichwas to cure wounds even when the patient was out of sight. This powder had extraordinary success, and its efficacy was almost universally acknowledged.

The more advanced minds were, in truth, not yet in the condition most favourable to the development of the positive sciences. They had passed, in great measure, into the metaphysical stage of thought, which naturally succeeded the superstitious phase; from which, however, they were not by any means completely emancipated. Men of the most daring and original minds were thus tainted with superstition and credulity. Luther believed that the devil tormented him with ear-ache; he emphatically enforced the duty of burning witches, and earnestly recommended some anxious parents to destroy their son, whom he declared to be possessed by an evil spirit! The belief in witchcraft was still universal, and the last witch was not burnt until 1722. Bishops, judges, magistrates, and learned men all agreed in crediting the reality of sorcery and the efficacy of astrology.

The metaphysical phase of thought, moreover, delayed the march

of knowledge, by leading men away from the search for facts into the labyrinths of abstract speculations. Men wasted their time and energies in discussing whether a spirit could live in a vacuum, and whether in that case the vacuum would be complete; and whether Adam and Eve, not being born in the natural manner, possessed the umbilical mark. They theorised concerning the nature or essence of vital principles, and other mysterious entities, and heaped hypothesis on hypothesis, careless of their foundations. Van Helmont, who is immortalised by the discovery of the gases, adopted as an established fact, a theory which he founded on the hypothetical "archæus" or entity of Paracelsus. The archæus being an immaterial force or spiritual agent, Van Helmont believed that each member of the body had its own particular archæus subordinate to the central or principal archæus, which he localised in the stomach; and as he found that nauseating medicines impaired mental vigour, he assigned to the stomach the seat of the intellect also. Thus, although he made great discoveries in chemistry, his physiology was wildly imaginary and unwarrantably assumptive, and detracts from the fame which his valuable researches in chemistry conferred upon him. The matter-of-fact Vesalius too, who had dared to fail in secing the openings through the septum of the heart, which Galen had declared to exist, did not dream of disputing the theory of that authority concerning the distribution of the blood, which required that the blood from the two ventricles should intermingle, and therefore imagined that it distilled through the pores of the unbroken and impermeable partition; and, contrary to what seems to have been his general temper, he steadily denied the existence of valves in the veins, which had been observed by others, although he might have verified their statements had he been in this instance open to conviction. Servetus also,-the victim of Calvin, who persecuted him even unto death, burning him and his works together at Geneva,—when he had discovered the pulmonary circulation, and almost grasped the great secret afterwards found out by Harvey, the complete circulation of the blood, instead of proceeding with the investigation, assumed all other errors except the one he had disproved, and describes how the air passes from the nose into the ventricles of the brain, and speculates how the devil takes the same route to the soul. The spirit of the age continued eminently unpractical, and men took interest in facts only as they could be bent to the support of preconceived theories, "spinning," as Lord Bacon says, "like the spider, the thread of speculative doctrine from within themselves," and regarding the perfection and symmetry of their production rather than its truth and certainty.

And yet there were men of true science, who did not suffer themselves to be led away into such speculations, but were content to record facts and make experiments, deducing therefrom no unwarrantable conclusions. One of the first among these was Ambroise Paris, a Frenchman. He devoted a life of nearly a century to the improvement of practical medicine and surgery, and as he enjoyed for the greater part of that time the highest reputation, his example and teaching must have had a most beneficial effect on the progress of scientific knowledge. His improvements were obstinately resisted by the surgeons of the sixteenth century, especially that of tying ligatures on wounded arteries, which they derided as an absurd mode of hanging life upon a thread, preferring the good old plan of searing the stump with a red-hot iron, which had stood the test of so many centuries. Harvey, Sydenham, Mead, Heberden, and Cullen steadily went on with the work of observation and record, and by the materials which they collected, and the cautious deductions which they drew, helped to confirm the healthy tone of thought which was gradually gaining ground amongst the educated classes. Thus science progressed, surely though slowly. Men had not, indeed, ceased altogether to believe in the efficacy of the royal touch as a remedy for scrofula, and physicians still discoursed at times of "salino-sulphureous impurities of the fluids" and "derangements of the temperies of the humours," of "distinct intelligent organic agents," and the "vis medicatrix naturæ;" but these fancies were mostly swept away by the additional impulse given to medical science by the labours of Boerhaave, William and John Hunter, and their pupil, Dr. Matthew Baillie. Boerhaave commenced systematic instruction in clinical medicine, and placed physiological science in immediate relation with pathological research, thus bringing new forces to bear upon the work of unravelling the secrets of nature. The Hunters worked out anatomy and physiology into almost minute perfection, and Dr. Baillie, by researches in morbid anatomy, and connecting these results with the observation of symptoms during life, threw great light upon the

science of disease.

The end of the eighteenth and the beginning of the nineteenth centuries form another epoch in the History of Medicine. Students of science had become more and more bent on original research, and less and less given to extravagant speculations. They had learnt "to seek the how instead of the why," the laws rather than the ultimate causes of phenomena. From this time discoveries in physiology and pathology succeeded each other with amazing rapidity. Jenner discovered vaccination, Laennec found out how to learn the condition of organs within the chest by

means of auscultation, and, after them, Bright, Marshall Hall, Brown-Sequard, Trousseau, Watson, and a hundred others have each added more to medical knowledge within our own recollection, than the whole series of philosophers from Galen to Paracelsus. The work accomplished in the last twenty or thirty years in these two sciences by the patient, systematic method of interrogating nature now adopted, exceeds what was accomplished in fifteen centuries under the pernicious influence of superstition, priestly repression-under the metaphysical phase of thought. Chemistry, the handmaid of medicine, revived by the labours of Cavendish, Priestley, Lavoisier, and Davy, has advanced along the same path with gigantic strides. The enormous extent of chemical knowledge in our time excites the most unqualified admiration, when we consider that it is almost entirely the work of the last hundred years, for that length of time has not yet passed since Cavendish first decomposed water and Priestley discovered oxygen.

To chemistry we owe the most valuable remedies of the present time, and by the gift of chloroform alone it has earned the eternal gratitude of mankind. The labours of such men as Harvey, Jenner, the Hunters, and Laennec, have conferred solid benefits on the human race, and will live for ever the admiration of the world. Their work is proved, and found true and enduring; while the wild speculations of Galen and his ten centuries of disciples, the false hypotheses of Servetus and Paracelsus, have already ceased to influence science, or, together with the reckless follies of innumerable Dr. Sangrados, remain but as wrecks to warn future explorers. But although we have just reason to be proud of our progress in anatomy and physiology, in chemistry and pathology, there is one branch of the science of medicine which lags terribly behind the rest. We have a satisfactory knowledge of the enemy with whom we have to deal in all his Protean forms, and of the structure of the citadel which we have to defend from his attacks; and we can tell with tolerable accuracy whether he is making slow and insidious approaches by sap and mine, or intends to take the fortress suddenly by storm. We understand that the weapons we wield are powerful engines of war, but we know not yet how to use them. We are fighting as it were in the dark, or at best in a dim uncertain light, and are ignorant often whether we strike friend or foe. We do not indeed slaughter recklessly and indiscriminately, as did our forefathers, cutting and slashing with closed eyes; but we are obliged to fence warily, sure indeed that our arms are effective against a few particular foes, yet giving blows, after all, at random against many, and perchance slaying allies or knocking a fatal breach unawares in the beleaguered fortress. To drop metaphor, although we are tolerably well acquainted with the signs and course

of disease, and the structure and functions of the various organs of the body, and are increasing our knowledge of these every day, we know little of the remedies we have to employ, and in this respect make hardly any perceptible advance. One or two drugs only do we possess which we can confidently affirm have a sure and constant effect in arresting particular diseases, as quinine in ague, and perhaps alkalies in acute rheumatism. For the rest, it may be said that we know of certain specific effects which they produce on the human economy; we can purge or cause to vomit, we can salivate with mercury and narcotise with opium; but whether these and like effects influence diseases for good or evil is generally uncertain. We feel assured that one general principle of treatment will not increase the mortality, and we hope lessens it, and that another will infallibly be most fearfully fatal. We know, for instance, that if we bleed a patient suffering from continued fever, or use remedies of powerful effect, he will almost surely die; but that if we content ourselves with alleviating the worst symptoms, and obviating the tendency to death until the violence of the disease be overpast, he will probably recover. Much has indeed been done to lessen the mortality from disease by improved sanitary measures, the results of which seem to be unmistakable. The general laws of health are better known than beforetime; we are far greater now in prevention than in cure; for the very drugs which we see have the most powerful and obvious action on the body are those concerning whose influence in disease the opinion of the medical faculty is the most divided. The BigEndians and the Little-Endians fight their battles by the invalid's bed as well as elsewhere. In truth, the poisonous action of drugs is well marked and unmistakable; but what we suppose to be their beneficial action may be merely the decline of the disease itself. We cannot make a healthy man better still by giving him drugs, but we can make him ill, and undoubtedly make him still worse afterwards, although probably not able to restore him to health again. On the very point on which the ancient physicians proudly boasted of their knowledge and success, and spoke and wrote with the greatest confidence, we feel ourselves painfully uncertain and miserably weak. Therapeutics, the crowning point of medical science, the ultimate end and aim of all research in the various sciences on which it is built, it must be confessed is yet in its veriest infancy. But at this, it appears to me, we need neither be surprised nor disheartened. The science is still partly in the superstitious, partly in the metaphysical stage. It could not be otherwise. There is no groundwork on which to form a positive science. The action of medicines must be traced through a series of complex laws of organic chemistry, and nervous action, and of these we hardly