WILLIAM HARVEY. 



335 



WILLIAM HARVEY. 



Br T. II. HUXLEY. 



OX the coming 1st of April, three hundred 

 years will have elapsed since the birth of 

 William Harvey, who is popularly known as the 

 discoverer of the circulation of the blood. 



Many opinions have been held respecting the 

 exact nature and value of Harvey's contributions 

 to the elucidation of the fundamental problem of 

 the physiology of the higher animals ; from those 

 which deny him any merit at all — indeed, round- 

 ly charge him with the demerit of plagiarism — to 

 those which enthrone him in a position of su- 

 preme honor among great discoverers in science. 

 Nor has there been less controversy as to the 

 method by which Harvey obtained the results 

 which have made his name famous. I think it is 

 desirable that no obscurity should hang around 

 these questions ; and I add my mite to the store 

 of disquisitions on Harvey which this year is 

 likely to bring forth, in the hope that it may help 

 to throw light upon several points about which 

 darkness has accumulated, partly by accident and 

 partly by design. 



Every one knows that the pulsation which 

 can be felt or seen between the fifth and sixth 

 ribs, on the left side of a living man, is caused 

 by the beating of the heart; and that, in some 

 way or other, the ceaseless activity of this organ 

 is essential to life. Let it be arrested, and, in- 

 stantaneously, intellect, volition, even sensation, 

 are abolished, and the most vigorous frame col- 

 lapses, a pallid image of death. 



Every one, again, is familiar with those other 

 pulsations which may be felt or seen, at the 

 wrist, behind the inner ankle, or on the temples ; 

 and which coincide in number and are nearly 

 simultaneous with those of the heart. In the 

 region of the temples, it is easy, especially in old 

 people, to observe that the pulsation depends on 

 the change of form of a kind of compressible 

 branched structure which lies beneath the skin, 

 and is termed an artery. Moreover, the least ob- 

 servant person must have noticed, running be- 

 neath the skin of various parts of the body, no- 

 tably the hands and arms, certain other bluish- 

 looking bands which do not pulsate, and which 

 mark the position of structures somewhat like 

 the arteries, which are called veins. 



Finally, accidental wounds have demonstrated 

 to all of us that the body contains an abundance 



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of a warm red fluid — the blood. If the wound 

 has traversed a vein, the blood flows in torrents 

 from its interior, in an even stream ; if it has in- 

 volved an artery, the flow takes place by jerks, 

 which correspond in interval with the pulsations 

 of the artery itself, and with those of the heart. 



These are facts which must have been known 

 ever since the time when men first began to at- 

 tend to and reflect upon the every-day course of 

 Nature, of which we form a part. I doubt not, 

 also, that butchers, and those who studied the 

 entrails of animals for purposes of divination, 

 must very early have noticed that both the ar- 

 teries and the veins are disposed in the fashion 

 of a tree, the trunk of which is close to the 

 heart, and connected with it, while the branches 

 ramify all over the body. Moreover, they could 

 not fail to observe that the heart contains cavi- 

 ties, and that some of these communicate with 

 the stem of the arteries, and some with the stem 

 of the veins. Again, the regular rhythmical 

 changes of form, which constitute the beating of 

 the heart, are so striking in recently-killed ani- 

 mals, and in criminals subjected to modes of pun- 

 ishment which once were common, that the dem- 

 onstration that the heart is a contractile organ 

 must have been very early obtained, and have 

 thus afforded an unintentional experimental ex- 

 planation of the cause of the pulsation felt be- 

 tween the ribs. 



These facts constitute the foundation of our 

 knowledge of the structure and functions of the 

 heart and blood-vessels of the human and other 

 higher animal bodies. They are to be regarded 

 as parts of common knowledge, of that informa- 

 tion which is forced upon us whether we desire 

 to possess it or not ; they have not been won by 

 that process of seeking out the exact nature and 

 the causal connection of phenomena, to the re- 

 sults of which the term science may properly be 

 restricted. 



Scientific investigation began when men went 

 further, and, impelled by the thirst for knowl- 

 edge, sought to make out the exact structure of 

 all these parts, and to comprehend the mechani- 

 cal effects of their arrangement and of their ac- 

 tivity. 



The Greek mind had long entered upon this 

 scientific stage, so far back as the fourth century 

 before the commencement of our era. For, in 



