Fabricius, Harvey’s teacher of anatomy, had made such a distinct step in advance in discovering the valves of the veins and the effect they must have, that it is quite astonishing that he should not have proceeded farther. But the fact is, that without the microscope as developed in after years,[5] it was impossible to solve a multitude of questions satisfactorily, and we may rather marvel that Harvey was able to achieve so much with the means at his disposal. The principal means he employed to this end was undoubtedly the vivisection of animals.
Chapter i. of his celebrated treatise on the Motion of the Heart and the Blood (Frankfort, 1628) begins emphatically, “When I first gave my mind to vivisections, as a means of discovering the motions and uses of the heart, and sought to discover these from actual inspection, and not from the writings of others, I found the task so truly arduous, so full of difficulties, that I was almost tempted to think, with Fracastorius, that the motion of the heart was only to be comprehended by God.[6]
“At length, and by using greater and daily diligence, having frequent recourse to vivisections, employing a variety of animals for the purpose, ... I thought ... that I had discovered what I so much desired, with the motion and the use of the heart and arteries....
“These views, as usual, pleased some more, others less; some chid and calumniated me, and laid it to me as a crime that I had dared to depart from the precepts and opinions of all anatomists.... At length, yielding to the requests of my friends, that all might be made participators in my labours, and partly moved by the envy of others, who, receiving my views with uncandid minds and understanding them indifferently, have essayed to traduce me publicly, I have been moved to commit these things to the press.... Finally, if any use or benefit to this department of the republic of letters should accrue from my labours, it will perhaps be allowed that I have not lived idly, and, as the old man in the comedy says:—
‘For never yet hath any one attained
To such perfection, but that time, and place,
And use, have brought addition to his knowledge;
Or made correction, or admonished him,
That he was ignorant of much which he
Had thought he knew; or led him to reject