214 PHYSIOLOGY CHAP. 



which he imitated systole by compressing it with his hand, and 

 diastole by simply releasing it. On sinking the heart in a vessel 

 of water, he was able at each compression to drive a jet of fluid 

 through the arteries, a proof that, after releasing the ventricles, 

 the internal cavity distended and filled with water. It was 

 objected to this experiment that the phenomenon might be due 

 to cadaveric rigidity of the heart : Goltz and Gaule, however, 

 regarded the elastic reaction of the heart at the commencement 

 of diastole as proved by their experiments with the minimum 

 manometer. 



The same view was taken by De Jager, who met every con- 

 ceivable objection to the theory that the filling of the heart at the 

 commencement of diastole depended not on the vis a tergo of the 

 blood, but on the elastic reaction of the heart's walls, by the fact 

 that, after opening the thorax, pressure is at zero in the cavity of 

 the right auricle and adjacent vein. This one fact is sufficient 

 to establish the doctrine of diastolic activity in the mechanical 

 sense. 



But in this connection arises the question of the origin of this 

 elastic reaction at the commencement of diastole. Is it dependent 

 on cardiac muscle properly so-called, or on the elastic tissue 

 implanted in the walls of the heart ? Certain authors subscribe in 

 virtiie of quite independent arguments to the former of these 

 theories, admitting a possibility of an active lengthening of the 

 muscular fibres of the myocardium. The first to express this 

 view was the English physiologist Carpenter, who, at the end of 

 1855, maintained that the active force which causes the heart to 

 dilate must originate in the myocardium proper. He propounded 

 the hypothesis that just as active muscular contraction, which 

 causes the muscle to shorten, depends on the attraction of the 

 particles of which that muscle is formed, so the reciprocal re- 

 pulsion of those same particles must produce the active elongation 

 of the muscle fibre. 



In 1871, not being aware of Carpenter's hypothesis, we brought 

 forward another, essentially similar to it, but differently expressed. 

 We suggested that the contraction and subsequent expansion of 

 the myocardium might be determined by two antagonistic 

 physiological processes, so that the cardiac diastole would, like 

 the systole, be an active movement. At a later time this hypo- 

 thesis was taken up and elaborated by Stefani (infra'). 



Lastly, mention must be made of Albrecht, who has recently 

 (1903) published a valuable study on the myocardium. He, too, 

 considers diastole to be an active physiological process, on the ground 

 of Verworn's theory of the general physiology of muscle. Accord- 

 ing to Verworn the expansive phase of the mechanical response 

 of muscle is active, and is determined by the tendency of the aniso- 

 tropous substance, saturated during the contractive phase by the 



