20 



HANDBOOK OF PHYSIOLOGY -^ CIRCULATION I 



The state of knowledge on cardiovascular physiol- 

 ogy at the beginning of the twentieth century was 

 admirably summarized with full documentation by 

 Leonard Hill (The Mechanism of the Circulation of 

 the Blood, in Text-Book of Physiology, edited by E. A. 

 Schafer, Edinburgh: Y. J. Pentland, 1900, vol. II, 

 pp. i~i68). In the same classic compendium, W. H. 

 Gaskcll summarized his own studies, in relation to 

 other pertinent contributions, on The Contraction of 

 Cardiac Muscle (ibid. pp. 169-227), which finally 

 established the validity of the myogenic theory of 

 cardiac contractility. The way had been paved in 

 part in Ludwig's laboratory, where Henry P. Bow- 

 ditch (1840-1911) of Boston had demonstrated the 

 all-or-none principle, and had shown that the frog- 

 heart's apex, devoid of ganglion cells, can beat rhyth- 

 mically. Another of Ludwig's famed pupils, Robert 

 Tigerstedt (i 853-1 923) of Helsinki, extended Gas- 

 kell's work, and closed his own career with a monu- 

 mental review of cardiovascular physiology {Physiologic 

 des Kreislaiifes. Berlin: de Gruyter, 1921). 



PROSPECT 



It is clear that Harvey started something. However, 

 the time was ripe for him. His demonstration about 

 blood circulation was clearly in the air. The surprising 

 thing is that it took so long to realize the practical 

 consequences of his little 1628 publication. This 

 historical survey has merely touched some of the high 

 points in the gradual accumulation of our verifiable 

 knowledge about the mammalian cardiovascular 

 system, before Harvey's time, and after him, until the 

 history merges into our current studies. The remainder 

 of this Handbook will indicate not only the amazing 

 extent of our present-day investigations in cardio- 

 vascular physiology, but also how each advance has 

 been made possible by a long succession of what has 

 gone before. Always both the stimulus and the goal of 

 this eflfort have been the same: to find what verifiable 

 and agreed-upon factors determine the normal ac- 

 tivity or malfunction of the .system, so that human 

 cardiovascular disease can be understood and 

 handled, and perhaps prevented. In this respect 

 cardiovascular pathology is to be considered as ab- 

 normal cardiovascular physiology, and historically 

 the two disciplines have gone together admirably. 

 That this joint \'enture will continue is now well 

 as.sured. 



Currently we are making amazing advances in the 

 understanding of cardiovascular physiologv: the 



brilliant but slowly acknowledged accomplishment of 

 Werner Forssmann (b. 1904) in catheterizing his own 

 heart and opening the way for the accurate diagnosis 

 of cardiac anomalies; the amazing development of 

 successful cardiac and vascular surgery, after the de- 

 velopment of effective anesthesia, asepsis, and blood 

 transfusion; the detailed analysis of the cardiac cycle, 

 with the pressure and electrical changes that accom- 

 pany each step, all giving direct improvement in di- 

 agnosis and management of cardiovascular disease, all 

 of this topped by the magnificent appreciation by the 

 American public of the importance of supporting 

 scientific study further. Here is a continuing climax of 

 progress stemming directly from the irascible seven- 

 teenth century Englishman, William Harvey. 



How far in the future did he project his thoughts 

 when he was writing, or traveling, or studying with his 

 secret feminine companion in his hidden retreat, or 

 dissecting and experimenting whenever he could? 

 How far ahead can we project our thoughts, visioning 

 what the future may hold in our knowledge and con- 

 trol of our hearts and blood vessels? It is a long way 

 from the emotional reactions of the writer of Genesis, 

 who believed, as did Aristotle, the wisest of the ancient 

 Greeks, that the heart was the seat of thought, to our 

 modern sophistication in being increasingly able to 

 manage the most difficult and obscure of cardiovascu- 

 lar disorders; but the path goes to Harvey, and from 

 him it has become a great highway of knowledge and 

 communication. Harvey painted his picture of the 

 heart and circulation in bold, simple, and very broad 

 strokes: since his time we have merely been filling in 

 the more obvious details with more precise and 

 delicate lines. The masterpiece, however, is still 

 Harvey's. 



BIBLIOGR.APHIC NOTE 



The foregoing account of the deselopmcnt of knowledge 

 about the vertebrate cardiovascular system deals mainly with 

 physiological aspects. Yet pathological factors have often 

 entered into the studies concerned. This is nicely illustrated in 

 the well-devised \olume prepared by F. A. VVillius and T. J. 

 Dry (.-1 History of the Heart and Circulation, Philadelphia: 

 Saunders, 1948, 473 pp.). Useful chronological appendices 

 consider anatomy, aneurysm, cardiac arrhythmia, cardio- 

 vascular diagnostic signs, congenital malformations, coronary 

 vessels and their diseases, electrophysiology and electrocardi- 

 ography, endocardium and its diseases, heart block, paroxysmal 

 tachycardia, pathology of the heart and circulation (in general), 

 pericardium and its diseases, physiology of the heart and circu- 

 lation, puke, surgery of the heart and vessels, symptoms of 

 diseases of the heart and circulation, and therapy of cardio- 



