208 PHYSIOLOGY CHAP. 



The highest figures for cardiac pressure were obtained by De 

 Jager, who employed a maximum manometer and a sound of wide 

 calibre, on large dogs. He found in three experimental series : 



i. n. in. 



In left ventricle . . . .235 174 111 mm. Hg. 



In aorta 212 162 158 



In right ventricle. ... 28 44 72 



These values are probably below the normal, since it cannot be 

 supposed that the introduction of a sound into the cavity of the 

 heart produces no disturbance of the systolic function. 



It would be more interesting to determine the exact relation 

 between the maximal pressure of the right and that of the left 

 ventricle, since these must harmonise with the different strengths 

 of the muscular walls of both ventricles, and with the different 

 resistances which the two vascular systems (aortic and pulmonary) 

 present. The experimental data so far obtained have not, how- 

 ever, led to any concordant results. On an average it may be 

 assumed that the pressure in the right ventricle and pulmonary 

 artery is to that of the left ventricle and aorta as 1 : 2*5, or 1 : 3 

 (Goltz and Gaule, Colin, Beutner). 



VII. The absolute values of negative intracardiac pressure 

 obtained with the minimum manometer are linked with the question 

 so much discussed in the last quarter of last century, i.e. the 

 determination of the mechanical factors by which the filling of 

 the ventricle during diastole is effected. 



The theory supported by Harvey and Haller, to the effect that 

 the diastolic filling of the heart occurs quite passively, from the 

 wave of blood which rushes from auricle to ventricle in presystole, 

 was for a long while accepted almost unanimously by physiologists. 

 The opposite theory, by which the heart acts as an aspirating pump 

 in diastole and as a pressure pump in systole, is, however, still 

 older, since it was formulated by Erisistratus and Galen, and 

 maintained at a later period by Vesalius, Bichat, Sprengel, and 

 Magendie, without indeed finding any large number of adherents. 



In 1871 we revived the theory of diastolic activity, on the 

 strength of certain rudimentary experiments, which may be 

 described as follows : 



(a) When in a dog with opened thorax a trocar is intro- 

 duced through the apex into the interior of one of the ventricles, 

 and a horizontal glass tube, open at the end, is attached to the 

 cannula, a jet of blood can be seen in the tube at each systole, 

 which recedes at each diastole. 



(&) If the pressor effect of the presystole is impeded by seizing 

 the walls of the auricle with a forceps, the diastolic aspiration 

 increases conspicuously. 



(c) If in consequence of vagus excitation, the heart's move- 



