CIRCULATION. 125 



M. The Pressures within the Ventricles.' 

 We must now approach the study of further details of the working of the 

 ventricular pumps, which details depend for their elucidation upon the measur- 

 ing and recording of the pressures within the ventricles. 



Absolute Range of Pressure -within the Ventricles and its Signifi- 

 cance. — In dealing with the work done by the contracting ventricles (p. 106) 

 we have seen that the mercurial manometer, as used for studying the pressure 

 within the arteries, is quite unable to follow the changes of the intra-ventric- 

 ular pressure; but that, by the intercalation of a valve, this instrument can he 

 converted into a useful " maximum manometer" for the measuring: and record- 

 ing of the highest pressure occurring within the ventricle during a given time 

 — that is, during a certain number of cycles. It must now be added that by a 

 simple change of valves this same instrument can at any moment be changed 

 into a "minimum manometer." 2 We can thus, by means of the modified mer- 

 curial manometer, learn with fair correctness the extreme range of pressure 

 within the ventricles. As instances of the extent of this range, two observa- 

 tions may be cited upon the left ventricle of the dog, the chest not having been 

 opened. In one animal the maximum was found to be 234 millimeters of mer- 

 cury, the maximum pressure in the aorta being 212 millimeters; and the min- 

 imum in the left ventricle was —38 millimeters — that is to say, 38 millimeters 

 less than the pressure of the atmosphere, the minimum pressure in the aorta 



1 The matters connected witli the ventricular pressure-curve may best be studied in the fol- 

 lowing writings, in which citations of other papers maybe found: K. Hiirthle, in Pfluger's 

 Archiv fiir die gesammte Physiologie, as follows: " Zur Technik der Untersuchung des Blut- 

 druckes," 1888, Bd. 43, S. 399. "Technische Mittheilungen," 1X90, Bd. 47, S. 1. "Ueber 

 den Ursprungsort der sekundiiren Wellen der Pulscurve," Bd. 47, S. 17. "Technische Mit- 

 theilungen," 1891, I'd. 49, S. 29. " Ueber den Zusammenhang zwischen Herzthatigkeit nnd 

 Palsform," Bd. 49, S. 51. " Kritik des Lufttransmissionsverfahrens," 1*92, Bd. 5:>, S. 281. 

 '' Vergleichende Priifung der Tonographen von Frey's nnd Hiirthle's," 1893, Bd. 55, 8. 319. 

 J. A. Tschuewsky : " Vergleichende Bestimmung der Angaben des Quecksilber — nnd des Feder- 

 Manometers in Bezugaufden mittleren Blutdnick," Pfluger's Archiv fiir du gesammte Physiologic, 

 1898, Bd. Ixxii. S. 585. "Technische Mittheilungen," Ibid., 1898, Bd. lxxii.S.566. K. Hiirthle: 

 " ( >rientirungsversuche iiber die Wirkung des Oxyspartein auf das I [erz, . I rchivfiir experimenteUe 

 Pathologie wnd Pharmakologie, 1892, Bd. xxx. S. 141. \V. I'. Porter: "Researches on the 

 Filling of the Heart." The Journal of Physiology, 1892, vol. xiii. p. 513. "A New Method for 

 the Study of the Intracardiac Pressure Curve," Journal of Experimental Medicine, L896 a vol. i.. 

 No. 2. M. von Frey und L. Krehl : " Untersuchungen iiber den Puis," Archiv fiir Anaiom.it und 

 Physiologie, Physiologische Abtheilung, 1890, S. 31. M. von Frey: "Die Untersuchung des 

 Pulses," Berlin, 1892. "Das Plateau des Kammerpulses," Archiv fiir Anatomie und Phynolagie, 

 Physiologische Abtheilung, L893, S. 1. "Die Ermittlung absoluter Werthe fiir die Leistung 

 von Pulsschreibern," Archiv fiir Anatomie und Physiologie, Physiologische Abtheilung, 1893, S. 

 17. " Zur Theorie der Lufttonographen," Archiv fiir Anaiomie und Physiologie, Physiologische 

 Abtheilung, 1893, S. 204. " Die Erwarmung der Full in Tonographen," Qmtralblatt fur Ph 

 wlogie vom 30 Juni, 1894, Heft 7. < >. Frank: " Ein experimentelles rlilfsmittel fiir Eine 

 Kritik der Karamerdruckcurven," Zeitschrifi fiir Biologie, 1897, Bd. sxxv 8 178. B. Rub- 

 brecht: "Recherches cardiograph iques chez les Oiseaux," Archives de Biologie, 1898, t. w. p. 

 <i47. .!. Waroux : " Du trace* myograph iqne due cceur exsangue," Ibid., 1898, t. sv. p. 661. 



2 F. Goltz und J. Gaule : " Ueber die Druckverhaltnisse iin [nnern des Herzens," Pfluger's 

 Archiv fiir die gesammte Physiologie, 1878, wii. S. 100. 



