whether derived from vivesections and my various reflections on them, or from the ventricles of the heart and the vessels that enter into and issue from them, the symmetry and size of these conduits-for Nature doing nothing in vain, would never have given them so large a relative size without a purpose, or from the arrangement and intimate structure of the valves in particular, and of the other parts of the heart in general, with many things besides, I frequently and seriously bethought me, and long revolved in my mind, what might be the quantity of blood which was transmitted, in how short a time its passage might be effected, and the like; and not finding it possible that this could be supplied by the juices of the ingested aliment without the veins on the one hand becoming drained, and the arteries on the other getting ruptured through the excessive charge of blood, unless the blood should somehow find its way from the arteries into the veins, and so return to the right side of the heart; I began to think whether there might not be a motion, as it were, in a circle. Now this I afterwards found to be true; and I finally saw that the blood, forced by the action of the left ventricle into the arteries, was distributed to the body at large, and its several parts, in the same manner as it is sent through the lungs, impelled by the right ventricle into the pulmonary artery, and that it then passed through the veins and along the vena cava, and so round to the left ventricle in the manner indicated. Which motion we may be allowed to call circular, in the same way as Aristotle says that the air and the rain emulate the circular motion of the superior bodies; for the moist earth warmed by the sun evaporates; the vapours drawn upwards are condensed, and descending in the form of rain moisten the earth again, and by this arrangement are gene rations of living things produced; and in like manner, too, are tempests and meteors engendered by the cir

cular motion, and by the approach and recession of the

sun.

"And so in all likelihood does it come to pass in the body, through the motion of the blood; the various parts are nourished, cherished, quickened by the warmer, more perfect, vaporous, spirituous, and, as I may say, alimentive blood; which, on the contrary, in contact with these parts, becomes cool, coagulated, and, so to speak, effete; whence it returns to its sovereign, the heart, or to the inmost home of the body, there to recover its state of excellence or perfection. Here it resumes its due fluidity, and receives an infusion of natural heat-powerful, fervid, a kind of treasury of life, and is impregnated with spirits, and, it might be said, with balsam; thence it is again dispersed, and all this depends on the motion and action of the heart.

"The heart consequently is the beginning of life; the sun of the microcosm, even as the Sun, in his turn, might well be designated the heart of the world; for it is the heart, by whose virtue and pulse the blood is moved, perfected, made apt to nourish, and is preserved from corruption and coagulation; it is the household divinity which, discharging its function, nourishes, cherishes, quickens the whole body, and is, indeed, the foundation of life, the source of all action. But of these things we shall speak more opportunely when we come to speculate upon the final course of this motion. of the heart.

"Hence, since the veins are the conduits and vessels that transport the blood, they are of two kinds-the cava and the aorta; and this is not by reason of there being two sides of the body, as Aristotle has it, but because of the difference of office; nor yet, as is commonly said, in consequence of any diversity of structure; for in many animals, as I have said, the vein does not differ from the artery in the thickness of its tissues, but solely in virtue of their

symptoms so long as her weakness remains; and, like a penitent, ashamed of the recent stormy swelling, may begin to think of the propriety of concocting pus, as soon as possible, out of extravasated blood. But the desired effects would follow more naturally and more propitiously, if you retained the blood in which the life-that is, the vital power-resides. For Nature, the only healer of disease, is emphatically life, and when that goes, the physician can only shrug his shoulders."1

These are strong expressions to come from a master in Israel. They read like the fierce denunciations of some outlaw, such as Paracelsus. "With pleasure," says Sprengel, "does the lover of truth hang over the writings of the man who, however much he adhered to the mysticism of his age, yet exposed innumerable theoretical and practical errors, and expounded principles which later physicians ignorantly regarded as the fruits of after discoveries. By the incorruptible tribunal of History will the chaplet of merit be awarded to this forgotten physician of the olden time. He has had, like other bold innovators, to wait about two hundred years for this justice. By his contemporary, Guy Patin, he was represented as having died raving mad, from his aversion to blood-letting. Van Helmont's son, however, Francis Mercius, who attended his father on his death-bed, says, that this report of his being a victim to his horror of bloodshed, is entirely false and calumnious.*

2

Deprived of the dangerous weapons then in use for combating disease and human life, Van Helmont had recourse naturally to the new medicines, mercury and antimony, and also used wine and opium largely, with what success we are not informed; and, indeed, his thera

1 Opera omnia, p. 387.

2 Sprengel, Vol. IV., p. 316.

3 Lettres de Guy Patin, Vol. I., p. 14. Cologne, 1691.

See the Introduction, written by his son, to his "Opera omnia," which he edited.

peutic doctrines are chiefly interesting in their negative relations. In these alone have they survived historically. He died in 1644, in the sixty-seventh year of his age, bequeathing to his son all his writings, none of which were published in his lifetime.

While Van Helmont was the exponent of the speculation of his age, in the direction both of vitality and chemistry, William Harvey served himself heir to the land of promise pointed out by Lord Bacon, in the kingdom of simple observation and direct experiment. His life presents a great contrast to that of his contemporary. Van Helmont was a brilliant meteor, a gasiform body shooting across the planet's orbit-dazzling, but soon lost to view; Harvey, a planet moving in steady radiance," without haste and without rest," and contributing for ever and for ever his proper tones to the everlasting music of the spheres.

1 From a picture by Rennel, in the collection of Dr. Mead.

The incidents of his life are of the most common-place. His father, Thomas Harvey, was an opulent yeoman of Kent. His mother was "a godly, harmless woman; a chaste, loving wife; a charitable, quiet neighbour; a comfortable, friendly matron; a provident, diligent housewife; a careful, tenderhearted mother." So runs the epitaph written by her son.1 He was born at Folkestone, in the year 1578, one year after Van Helmont, and eighteen years after Lord Bacon. At the age of sixteen, he went to Cambridge; and three years afterwards, took the degree of B.A. He then began his medical studies at the famous University of Padua, under Fabricius of Aquapendente, for whom he entertained the highest respect, and who put him on the sure path of his great discovery. After having spent between three and four years at Padua, he returned to England and took his degree of M.D. at Cambridge. Five years afterwards, he was admitted as a Fellow of the College of Physicians. At the age of thirty-one he was appointed Physician to St. Bartholomew's Hospital; and in the year 1615, when thirty-seven years of age, he began his course of lectures upon the motions of the blood. There is no report of these lectures, but it is believed they contained the substance of what he published thirteen years afterwards, in Latin, of which the English translation is "An Anatomical Disquisition on the Motion of the Heart and Blood in Animals.” This book, which is a milestone on our road, bears date 1628. It is dedicated to King Charles I., who took a deep interest in Harvey's discovery, and five years afterwards appointed him physician to his royal person. This was some recompense for the treatment he received from his colleagues on account of the novelty of his views. "I have heard Harvey say," writes Aubrey, "that after his book on the circulation of the blood came out, he fell

Harvey's Life, p. xviii., Note.