i6 



HANDBOOK OF PHYSIOLOGY 



CIRCULATION I 



in spite of long delays in accepting his conclusions or 

 in making practical applications of them in medical 

 practice, Harvey's 1628 publication really began 

 modern physiology and medicine. 



As pointed out in the preface to my tercentennial 

 translation, the differences in Harvey's style in the 

 book suggest that it was written at different times. 

 The introduction, in critique of the Galenical dogma, 

 is vigorous and youthful. The first chapter, however, 

 apologizing for the effort, has the meditative calm of 

 middle age. The last three chapters seem like after- 

 thoughts: they are appendages trying to reconcile 

 opposing viewpoints without adequate data. In 

 chapters two to five there is the careful analysis of ob- 

 served phenomena; in chapters ten, eleven, and thir- 

 teen there are offered experimental results to test the 

 proposed hypothesis, while chapters nine, ten, and 

 thirteen give quantitative reasoning to prove the 

 brief conclusion offered in chapter fourteen. Chapter 

 eight offers the hypothesis, while the last three chap- 

 ters are largely speculative. The sixth and seventh 

 chapters, on the pulmonary circulation, are puzzling. 

 Harvey seems to have taken it for granted, as Donald 

 Fleming so well argues {Lis 46: 319-327, 1955). 

 There is discussion of the comparative and embryo- 

 logical aspects of the matter, and then an interesting 

 return to the authority of Galen as evidence. Harvey 

 really was interested in demonstrating the circulation 

 of the blood in general in all animals, and the pulmo- 

 nary circulation may have seemed unessential to him 

 in this regard.^ 



Apart from measuring blood volume by drainage 

 in sheep and probably some other mammals, Harvey 

 made no actual measurements in regard to circula- 

 tion. Yet he used quantitative reasoning in a most 

 effective way to prove his point. First, he considered 

 the amount of blood put out by the heart in a single 

 beat, and then showed that the amount which would 

 be forced out of the heart in a relatively short while, 

 say an hour, would be much more than could be in 

 the body at any one time, as he knew from having 

 measured blood volume. His figure here, of about 

 one-tenth body weight, is fair. In the interesting illus- 

 trations to the book, which are styled like those illus- 

 trating Fabrizzi's work on the venous valves, the 

 function of the valves is made clear, and again there 

 is demonstration of the fact that by milking an arm 

 vein rapidly, one can have pass under one's finger in 



' According to F. J. Cole (J. Hist. Med. 12: 106-113, 1957), 

 Harvey indicates that he studied 1 28 types of animals, from 

 zoophytes, through worms, Crustacea, insects, and \arioiis 

 kinds of vertebrates, to many species of mammals. 



not too many minutes more blood than there is in the 

 whole body. Obviously it must be the same blood 

 going around in a circulation. 



Lack of satisfactory application of Harvey's demon- 

 stration to practical medicine made it relatively un- 

 appreciated for more than a century, except as a 

 matter of scientific interest. Indeed, William Welch, 

 wise Nestor of American medicine, once surmised 

 that the practical demonstration of Thomas 

 Sydenham (1624-1689) of the curative effect of 

 cinchona bark in fever, regardless of any connection 

 with accepted dogma, had a greater influence in over- 

 throwing Galenical tradition than did Harvey's 

 demonstration of the circulation.^ 



HARVEY S FOLLOWERS 



Actually Harvey's demonstration of the circulation 

 was not complete: he had to postulate capillary anas- 

 tomoses between arteries and veins; he could not find 

 them since he had no microscope. They were found 

 by Marcello Malpighi (1628- 1694) in 1661 while 

 studying the lungs of frogs, and Antonj van 

 Leeuwenhoek (1632-1723), who first described work- 

 able microscopes, also observed the capillaries. These 

 observations may have revived interest in Harvey's 

 demonstration from tlie standpoint of practical ap- 

 plication. 



Transfusions were attempted, but failed tragically, 

 probably because of what we now recognize as in- 



' Nevertheless, Harvey's demonstration was promptly ac- 

 cepted during the 17th century as a significant scientific contri- 

 bution for teaching. This is shown by the "first physiological 

 textbook," De homine figuris, Leyden, 1662, of Rene Descartes 

 (1596-1650), and by the reception of Harvey's work in Italy, 

 as described by W. Pagel & F. N. L. Poynter {Bull. Hist. Med. 

 34: 419-429, i960), and even in America, as pointed out so 

 well by F. Guerra {Bull. Hist. .Med. 33: 212-229, 1959). An 

 early experimental confirmation of Harvey's findings was 

 written in 1652 by Henry Power (1623-1688), but has only 

 recently been published from manuscript (F J. Cole, J. Hist. 

 Med. 12: 291-324, 1957). By an interesting coincidence, a 

 contemporary poem published in 1656 by John Collop (1625- 

 post 1676) in praise of Harvey and the circulation, was simul- 

 taneously rediscovered by F. N. L. Poynter & C. Hilberry 

 {J. Hist. Med. 11: 374-411, 1956). E. Weil {J. Hist. Med. 12: 

 167-174, 1957) lists 69 publications referring to Harvey's 

 work, from its initial appearance, by Robert Fludd (1574- 

 1637), in 1629, to 1656, the year before Harvey died, when 

 Collop's poem appealed. .As L. R. O. Agnew indicates, Har- 

 vey's report was so intellectually stimulating to his contempo- 

 raries that it could result in another rhapsodic poem from the 

 Bishop of Chichester, Robert Grove (1634- 1696), published in 

 1685 {Bull. Hist. .\ted. 34: 318-330, i960). 



