Harvey then noted a well-known clinical fact, that the more frequent or forcible the pulsations, the more speedily might the body be deprived of its blood during hemorrhage, and that it thus happens that in fainting fits and the like, when the heart beats more languidly, hemorrhages are diminished and arrested. The balance of the book is practically devoted to further demonstration and corroboration of statements already made. A study of this work of Harvey's illustrates how much respect even he and his contemporaries still showed for the authority of Galen. It shows still further how nearly Galen came to the actual truth concerning the circulation. Had the latter not adopted too many of the notions of his predecessors concerning the nature of the soul (Anima) and the spirits (Pneuma) of man, he might himself have anticipated Harvey by a thousand years, and by such announcement of a great truth have set forward physiology by an equal period. Independent and original as Harvey showed himself, he seems to have failed to get away from the notion of the vapors and spiritual nature of the blood which he had inherited from the writings of Galen and many others. Nevertheless he also alludes to this same blood as alimentive and nutritive. We must not forget, however, that this was years before Priestly's discovery of oxygen and that Harvey had, like others, no notion of the actual purpose of the lungs, believing that the purification and revivification of the blood was the office of the heart itself. Along with its other intrinsic merits Harvey's book possesses a clear and logical arrangement, the author first disposing of the errors of antiquity, describing next the behavior of the heart in the living animal, showing its automatic pumplike structure, its alternate contractions and the other phenomena already alluded to, thus piling up facts one upon another in a manner which proved quite irresistible. The only thing that he missed was the ultimate connection between the veins and the arteries, i. e., the capillaries, which it remained for Malpighi to discover with the then new and novel microscope, which he did about 1657, showing the movement of the blood cells in the small vessels, and confirming the reality of that ultimate communication which had been held to exist. Malpighi discovered the blood corpuscles in 1665, but it remained for Leeuwenhoek, of Delft, in 1690, by using an improved instrument to demonstrate to all observers the actual movements of the circulating blood in the living animal. One historian has said that with Harvey's overthrow of the old teachings regarding the importance of the liver and of the spirits in the heart "fell the four fundamental humors and qualities" while Daremberg exclaims: "As in one of the days of the creation, chaos disappeared and light was separated from darkness."