circumstances spontaneously furnished by Nature; in the other, we obtain it from experiment, which possesses the great advantage over observation not only of furnishing us with a much greater number of variations than is to be found naturally presented, but also of enabling us to produce the precise form of combination or variation which is needed for our purpose.
Harvey, in a true sense, adopted the Baconian system of interrogating Nature by appeal to observation and experiment, and drawing conclusions out of the facts presented, and yet it is evident that the Novum Organum" was not published till after the discovery of the circulation was made. Bacon's new method of conducting research and discovering the truths of Nature was placed before the public in 1620. Harvey's work on the circulation, "Exercitatio Anatomica de Motu Cordis et Sanguinis Animalibus," was not "published till 1628, but it has been generally allowed that his discovery was made known in his first course of Lumleian lectures, delivered at the college in 1616; and, thanks to the meritorious labors of a committee of the college, this has now been rendered open to verification by the very interesting volume just prepared, and on the point of being issued, containing a reproduction in autotype form of his original lecture-notes in his own handwriting. Harvey, then, must have been thoroughly in the van of progress taking place in his day; and, further, the contemporaries of Bacon must have been acquainted with the new system of philosophy before the "Novum Organum" was published.
Harvey's discovery established a new departure in physiology. Without a knowledge of the circulation, nothing really could be known about the various operations taking place within us. It is hard, with the knowledge now possessed, to realize the state existing at the time the circulation was discovered. The passage of blood from the right to the left side of the heart had, it is true, already been recognized, but it was taught that the blood went to the lungs for their nutrition, and "to be elaborated and subtilized by the reception of a spirit from the air in inspiration, and the exhalation of a fuliginous matter in expiration." The heart and arteries were supposed to be the seat of the vital spirit, and the liver to be the fountain whence the body was supplied with blood through the veins, in which there was believed to be a to-and-fro current, a flux and reflux, that was compared to the ebb and flow of the tide in the classic straits of Euripus. Truly, indeed, may it be asserted, that our ancestors stand in the twofold position of our parents with respect to age, our children with respect to knowledge.
It was not without opposition that Harvey's views were received; and the high position in his profession he had attained did not suffice to prevent his escape from the effect of the prejudice against innovation entertained by the multitude. Aubrey tells us he had "heard him say that after his book on the circulation of the blood came out,
