circulation, as it is called, was again brought forward as an original discovery of his own by Realdus Columbus, in his work De Re Anatomica, published at Venice in that year. And, in 1571, Casalpinus of Arezzo, in his Quæstiones Peripateticæ, also published at Venice, inferred from the swelling of veins below ligatures that the blood must flow from these vessels to the heart. So far had the investigation of the subject, or rather speculation respecting it, proceeded when it was taken up by Harvey. From Fabricius ab Aquapendente, under whom he studied at Padua about the year 1600, Harvey, then in his twenty-second or twenty-third year, learned the fact of the existence of valves in many of the veins, which were evidently so constructed as to prevent the flow of blood in these vessels from the heart, and at the same time not to impede its motion in the opposite direction. According to Harvey's own account, given in a conversation with Boyle, which the latter has reported in his treatise on Final Causes, it was the existence of these valves in the veins that first suggested to him the idea of his general theory of the circulation. Having satisfied himself by much consideration of the subject, and by many dissections and other careful experiments both on dead and living bodies, that his views were at least in the highest degree probable, he is supposed to have first announced the doctrine of the complete circulation of the blood from the left ventricle of the heart through the whole system back to the right by means of the arteries and veins, in his delivery of the Lumleian lectures on anatomy and surgery before the College of Physicians in 1615. But it was not till the year 1619 that he came before the world with the full demonstration of his theory in his treatise entitled Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus. The best proof of the novelty of the views propounded in this work is furnished by the general incredulity with which they were received by the profession in every part of Europe. It is said that there was scarcely an instance known of the doctrine of the circulation being accepted on its first promulgation by any anatomist or medical man who had passed his fortieth year. It is probable, indeed, that even the small circulation, or the passage of the blood from the right

relating to the circulation of the blood is extracted at length. It is remarkable, however, that what is believed to be the original manuscript, in the author's own handwriting, of the First Part of the Christianismi Restitutio also still survives. See De Bure, i. 423, 424.

to the left ventricle of the heart through the lungs, which was really all that had been hitherto discovered, was as yet but little known, or generally looked upon rather as at most an ingenious supposition than a well-established fact. At all events there can be no doubt that, beyond this point, all was darkness and error— that, notwithstanding some vague, inaccurate generalizations that had been thrown out by Servetus, Columbus, and one or two other writers, the circulation of the blood through the whole course of the arteries and veins, so far from being believed in, had scarcely been heard of or dreamed of by anybody before it was demonstrated by Harvey. The notion, we may say, universally entertained still was, as in the earliest times, that the veins were merely sacks of stagnant or at least unprogressive blood, and the arteries nothing more than air-tubes. Harvey himself, in proceeding to propound his theory, expresses his apprehension lest the opposition of the views he is about to state to those hitherto entertained might make all men his enemies; and it appears that he encountered as much popular as professional opposition and odium by his book, which was looked upon as a daring attack at once upon antiquity, common sense, and Nature herself. It was indeed the beginning and proclamation of a complete revolution in medical science. If the circulation of the blood was true, the greater part of all that had been hitherto taught and believed on the subjects of anatomy and physiology was false. As has been strikingly observed by a writer of our own day, 66 a person who tries to imagine what the science of medicine could have been while it took no account of this fact, on which, as a basis, all certain reasoning about the phenomena of life must rest, is prepared for what old medical books exhibit of the writhings of human reason in attempts to explain and to form theories while a fatal error was mixed with every supposition.'

Harvey, whose life was extended to the year 1658, contributed to the improvement of anatomical and physiological knowledge by various subsequent publications; and the progress of discovery in this department was also aided by others of our countrymen, particularly by Dr. Nathaniel Highmore (who has given his name to that cavity in the upper jaw called the Antrum Highmorianum), Dr. Francis Glisson (the discoverer of what is called the capsule of Glisson, lying between the liver and the * Arnott's Elements of Physics, 4th edit. i. 519.

stomach), Dr. Jolyffe, Dr. Thomas Wharton, and Drs. Thomas Willis and Richard Lower, celebrated as the first accurate anatomists of the brain and nerves. Some of the most important publications of the three last mentioned, however, were not produced till after the Restoration. In natural history little was done in England in the earlier half of the seventeenth century. The great authority in botany was still the Herbal, or General History of Plants, of John Gerard, originally published in 1597, which was for the most part merely a hasty and inartificial compilation from Dodonæus, and nearly as destitute of scientific as of literary merit.

NATURAL PHILOSOPHY.

But even in the mathematico-physical sciences, and the other branches of what is commonly called natural philosophy, it is wonderful how little general effect appears to have been produced in this country either by the example or by the actual discoveries of Kepler, Galileo, Torricelli, Pascal, Des Cartes, and their associates and immediate successors abroad, and of Napier, Briggs, Horrocks, and the few others among ourselves whose names have a place in this period of the history of science beside those of their illustrious continental contemporaries ;— how little of the general darkness they had dispersed-how little acceptance, or even attention, either their doctrines or the spirit of their philosophy seem to have met with from the common herd of our English speculators and professional men.

Some notion of the barbarous state in which physical science still remained among us after the middle of the seventeenth century may be obtained from a curious volume entitled Archelogia Nova, or New Principles of Philosophy, which was published in the year 1663 by a Dr. Gideon Harvey, who had held the high office of physician to the forces in Flanders, and may be therefore regarded as having stood nearly at the head of his profession. Besides an introduction on philosophy in general, Dr. Harvey's work treats of metaphysics and of natural theology, as well as of natural philosophy or physics; but the last mentioned subject occupies the greater portion of the book. The author makes an apology in his preface for some deficiency of polish in his style; the learned tongues, he would have us

So.

understand, apparently, had occupied his whole time to the exclusion of the vernacular : "It was never my fortune," he says, "to read two sheets of any English book in my life, or even to have had the view of so much as the title-leaf of an English grammar." His English certainly is not always very classical; but the language of his explanations and reasonings would usually be intelligible enough if the matter were equally The work, as we have seen, professes to be a new system of philosophy; and it does contain, certainly, various new crotchets; but the author's views are founded, nevertheless, in the main upon the old Aristotelian and mediæval notions, and one of his principal aims throughout is to refute the recent innovators who in so many departments had been questioning or denying these long universally admitted dicta. Thus, in an early chapter, he falls with great violence upon Van Helmont for his dissent from the authority of Hippocrates, Galen, and Aristotle in various points of physical doctrine, and especially for his rejection of the four elements. Afterwards he attacks Des Cartes, whom he charges with no fewer than seventeen serious errors; amongst which are, that the moon and the other planets borrow their light from the sun "_" that the earth is nothing different from a planet, and consequently that the other planets are inhabitable "—" that the moon is illuminated by the earth" and "that he assumes most of the erroneous opinions of Copernicus." Harvey, however, professes to be quite a commonsense philosopher: "The only instruments," he says in his preface," that I have employed in the sounding of the nature of things are the external senses, assuming nothing, or concluding no inference, without their advice and undoubted assent, whether in metaphysics, theology, or natural philosophy. Those terms or notions that only give a confused testimony of their being to the understanding, escaping the evidence of external sense, we have declined, as rocks whereon any one might otherwise easily make shipwreck of his sensible knowledge." His practice, however, does not always exactly square with these professions. Take for example a portion of his demonstration of the existence of atoms, or, as he chooses to call them, minimas. "Is not time composed out of instants united, and motion out of spurts joined to one another? That there are instants and spurts the operations of angels do confirm to us." This is hardly keeping within the province of the senses. Nor is what follows in the most

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matter-of-fact style ;-in grinding any substance, if you continue the operation beyond a certain point, "you shall sooner," says our author, "grind it into clods and bigger pieces than lesser ; the reason is, because nature is irritated by the violence and heat of grinding to call the air to its assistance, which glueth its body again together."* The historical deduction of the created universe from the original chaos, and much argumentation that follows touching the essential qualities and forms of things, may be passed over. But we may abridge a speculation about the phenomena of drowning which occurs in one of the chapters.

The true reason, we are told, had never before been laid down by any, why "a man yet living, or any other creature when alive, is much heavier than when he is dead." That such is the fact, in the first place, is assumed from a living man sinking at first when he falls into the water, and rising again to the top after he has been dead for some time. "The reason is," proceeds our philosopher, "because, through the great heat which was inherent in that man, the heavy and terrestrial parts were the more detained from the centre; they, again, being thus detained, moved stronger towards the centre, and therefore make the body heavier during their violent detention, through the great heat which was in the said man when alive; so that, through this great weight, the alive body sinks down to the bottom. Now, when a man is suffocated, and the heat squeezed out of him by the thick compressing parts of the water, then he is rendered less heavy, and immediately leaves the inferior parts of water, as being less weighty than the said profound parts." So that we see one principle of Dr. Gideon Harvey's philosophy is, that weight is partly occasioned by heat-that the same substance is heavier or lighter according as it is hotter or colder. The further explanation, in the like strain, of the reasons that nevertheless detain the body below for a considerable time after it may be supposed to have become as cold as the pressure of the water can well make it, need not be quoted at length:-there still remain, it seems, certain "airy and fiery parts," after the vital flame has been extinguished, which it requires in most cases some days to overcome. A strong, compact, well-set man will be eight or nine days in ascending to the top, "because his heat was deeper, and in greater quantity impacted into his body;" and for the same reason, it is affirmed, such a man will

*Arch. Philos. Nova, Part ii. p. 29.