tenets he professed to follow, he condemned all curious speculations upon the intimate nature of disease, as incapable of proof, and therefore always useless and often hurtful; and maintained that the only trustworthy source of opinion in medicine is experience resulting from observations frequently repeated, and experiments cautiously varied; and that no theories worth attention can be framed until the recorded experience of many observers, under many different circumstances, and even through successive ages, shall be embodied into one general system; and he boldly declared his belief that every acute disease might then be cured. An instance, which unfortunately as yet stands alone in support of this rather sanguine expectation, may be taken from the history of small-pox. The observation of its contagious nature led to the general practice of inoculation, and this to the immortal discovery of Jenner, by which a disease but yesterday the scourge of the earth has been almost extinguished. It is remarkable that Sydenham, who first pointed out the important difference between its distinctive and confluent forms-who so materially improved the treatment by changing it from stifling to cooling-and who studied and has described it with a laborious accuracy hardly paralleled in the history of medicine-was not aware of this, to us, its most striking characteristic of contagion. A person conversant with such subjects will feel no surprise at this to the general reader it may be a sufficient explanation, that it lies dormant for ten days; and that as it can only be taken once, and was always prevalent in London, the number of persons susceptible at any given time, and in obvious communication with each other, were comparatively few; so that opportunities were not so likely to arise as might be imagined of tracing its progress in single families or neighbourhoods from one source of contagion.

Sydenham is justly celebrated for the happiness of his descriptions, and his skilful application of simple methods of cure, which are as effectual as they were novel in that age, when a medical prescription sometimes contained a hundred different substances; but he has merit of a

higher kind, as a discoverer of general laws. Among others, he was the first to notice that there is a uniformity in the fevers prevailing at any one time, which is subject to periodical changes; and that other acute diseases often partake largely of the same general character, and sometimes even merge in it altogether, as the plague is said to have swallowed up all other diseases. This, which he ascribed to some peculiar state of the atmosphere, he called its epidemic constitution; and to be aware of its vicissitudes must of course be very important to the physician as a guide to practice. The value of these laws, which Sydenham deduced from a multitude of observations, has been attested by almost every medical writer since his time.

Sydenham's works have been repeatedly printed in the original Latin, as well as in English and the Continental languages. His first work was published after he had been sixteen years in practice; the last, which he edited himself, is dated three years before his death; and an elegant compendium of his experience was published posthumously by his son. They all appear to have been extorted by the importunity of his friends or the misrepresentations of his enemies. It is said that they were composed in English, and translated into Latin by his friends Mapletoft and Havers: there is, however, little reason for attaching credit to this report, as we are assured, on the authority of Sir Hans Sloane, who knew him well, that Sydenham was an excellent classical scholar, and perfectly capable of expressing himself elegantly in Latin. They are most carefully written and clearly expressed, and bear marks of the utmost truth and impartiality in the narration of facts, and judgment in arranging them. They are not voluminous, as he studiously refrained from overloading them with trivial matter, and from entering into the detail of a greater number of cases than might be sufficient to illustrate his method of practice. His object was to confine himself to the results of his own observation: to this he pretty strictly adhered, so that little space is occupied in his writings by quotations or criticism. It must be admitted that he occasionally

lapses into theoretical discussion, in violation of his own principles; but as he seldom or never permitted his fancy to divert him from what was practically useful, he may be pardoned if, in that age of speculation, he could not entirely resist the seduction. A graver charge against him is, that he overlooked or undervalued the immense body of information to be obtained from examining the effects of diseased actions after death, and devoted himself too exclusively to the study of the symptoms during life, and the effect of remedies upon them. It is hardly a sufficient justification of a man of so much independence of spirit to reply, that such examinations were opposed by the prejudices of the age in which he lived. Others have overcome the same obstacles, and with them many of those difficulties which perplexed and misled even the mind of Sydenham. He had equal or greater difficulties to contend against in the deep-rooted absurdities of the chemical and mechanical schools, which in the early part of his life held an almost equally divided sway in medicine: the former originated with Paracelsus and his disciples, and had the advantage of a longer prescription; and the latter had received a fresh accession of strength from the recent discoveries of Harvey: both, however, gave way before his energetic appeal to fact and experience. Scarcely less credit is due to him for his successful opposition to the popular superstition in favour of a host of futile remedies, which are now happily consigned to oblivion with the family receiptbooks and herbals in which their virtues were paraded, than for his victory over false principles and dangerous rules of practice.

On the whole, it may be safely advanced that medicine, as a practical science, owes more to the closelyprinted octavo, in which the results of his toilsome exertions are comprised, than to any other single source of information.