HISTORICAL DEVELOPMENT OF CARDIOVASCULAR PHYSIOLOGY 



13 



function, thus beginning comparative anatomy and 

 physiology. He also started studies on embryology, 

 noting the developing chick, and observing that the 

 first thing to show life in the developing organism is 

 the beating heart. Centuries later his work on genera- 

 tion and on the heart influenced William Harvey. 



The study of human anatomy and physiology seem- 

 ingly began with Erasistratus, in Alexandria, in the 

 third century B.C. He first observed that arteries are 

 empty after death, and concluded that they must 

 carry air. He indicated that it is brought in the form of 

 "vital spirits" from the heart to all parts of the body. 



The work of Erasistratus was systematically de- 

 veloped by Galen (131-201 A.D.), a brilliant Greek 

 physician from Pergamon, who founded experimental 

 physiology, and was a resounding success as a 

 practicing physician in Rome. Actually Galen showed 

 that arteries contain blood, but he was so impressed 

 by the general theory which he had in mind, that he 

 did not grasp the significance of his observation. 



According to the Galenical tradition, elaborated 

 over many centuries, body function proceeds from a) 

 "coction" of food in the stomach, where it is prepared 

 for absorption by ducts from the intestines for transfer 

 to the liver; b) here it is made into blood containing 

 "nutritive spirits" necessary for nourishing all parts 

 of the body, and distributed thereto by \'eins; c) some 

 of these nutritive spirits, passing through pores in the 

 septum of the heart, are combined in the left chamber 

 of the heart with air coming froin the lungs, to form 

 the "vital spirits," necessary for life and heat in all 

 parts of the body, to which they are distributed, 

 through boiling over of the heart, bv arteries; and il) 

 some of the.se vital spirits, permeating the cribriform 

 plate, are con\erted in the brain into "animal spirits" 

 necessary for motion in e\ery part of the body, to 

 which they are distributed by nerves. 



This logical scheme, so easily correlated with the 

 Greek humoral pathology, became traditional dogma 

 during the Middle Ages, and various details were 

 elaborated by Arabic and medieval commentators. 

 Galenical generalities on the cardiovascular system 

 were important factors in justification of scholastic 

 dogma in medical practice. The Greek humoral 

 pathology, probably elaborated from earlier Egyptian 

 concepts, gave the rationale for diagnosis, prognosis, 

 and treatment. Health consisted in the balance of the 

 humors; disease resulted from an excess or deficiency 

 of any one. Sensible treatment consisted in removing 

 the excess, or in making up the deficiency. In a 

 plethora of blood, a vein should be opened and the 



excess removed. In a deficiency, the patient should 

 receive drugs which have the qualities of blood; that is, 

 heat and moistness, — like warm rusty water, or warm 

 red wine. It was the abuse of blood-letting, with the 

 obvious debilitating effect of blood loss even in 

 "sanguine" men, which gradually raised doubts 

 about the \alidity of Galenical cardiovascular detail. 



Jean Fernel (1497- 1558), the keen Parisian physi- 

 cian, began the questioning of scholastic tradition by 

 opposing routine blood-letting. Ambroise Pare (1510- 

 1590), the great humanistic surgeon to the French 

 kings, must have realized some of the fallacies of 

 Galenical cardiovascular theory as he pondered the 

 character of war wounds and reintroduced ligatures 

 for controlling blood loss from ruptured vessels. 



Meanwhile, there gradually accumulated know- 

 edge of the cardiovascular system as based on the 

 occasional and hurried dissection of human cadavers, 

 made legally available for teaching as part of the 

 formality of execution of criminals. Jacopo Berengario 

 da Carpi (1470-1550), professor of anatomy at 

 Bologna, described heart valves in his Isagogae, which 

 appeared in 1522. He followed the course of arteries 

 by injecting them with warm water, and he noted 

 cardiac dilatation. Guido Guidi (1500?- 1569), who 

 taught at Pisa, was skeptical of the scholastic teaching 

 of pores in the septum of the heart. Valves in the 

 veins were noted by C^arolus Stephanus (Estienne) of 

 Paris ( 1 500-1 564), and even by that staunch sup- 

 porter of Galen, Jacques Dubois, or Sylvius (1478- 

 1555), the great Parisian teacher. Neither had much 

 of an idea of the possible function of these tiny struc- 

 tures. 



That obser\ant chssector, Leonardo da \'inci 

 ( 1 452-1 519), distorted his beautiful anatomical 

 drawings to fit the scholastic tradition. However, he 

 did not show the pores in the septum of the heart as 

 going directly through from one \entricle to another. 

 Leonardo's drawings and notes indicate his interest in 

 the function of the cardiac valves. They also show his 

 appreciation of ecldv formation in blood flow. 



It was essentially the dogmatic character of this 

 doctrine which Harxey attacked so successfully in the 

 seventeenth century. Meanwhile, however, certain 

 changes and corrections in it had been recorded, but 

 not for general and public use. There was such a 

 weight of opinion for the conventional Galenical 

 tradition, and it was so logical and in accord with 

 churchly doctrine, that any modification of it was 

 simply neither noticed nor coinprehended. 



\Vhile Galen in his great physiological schema had 



