On the Form of the Intraventricular and Aortic 

 Pressure Curves obtained by a new Method 



by 



W. M. Bayliss, B. A. (Oxon.) B. Sc. (Lond.) and Ernest H. Starling, M. D. 



(Lond.) M. R. C. P. 

 From tlie Pliysiological Laboratory of Guy's Hospital. 



(With pi. XX and one cut.) 



It is not our purpose in the present paper to enter into a discus- 

 sion of the various forms of endocardial pressure curves obtained by 

 different observers with various methods of registration, nor do we 

 intend to review the history of the question; but shall content ourselves 

 with referring readers to Tigerstedt's account on pages 82 to 108 of 

 his „Lehrbuch des Kreislaufs" (1893). 



In view of the difference of opinion as to the true form of the 

 intraventricular pressure curve, we thought it advisable to attempt 

 the registration of the curve by a totally different method and this 

 as simple a one as possible; accordingly, we devised the manometer, 

 a short account of which was published in the Guy's Hospital Eeports, 

 1892, p. 307. In this instrument, we photograph the changes of 

 volujiie of a small air-space at the end of a capillary glass tube, con- 

 nected directly with the cavity (left ventricle or aorta), the variations 

 of pressure within which we desire to investigate. To do this, a 

 piece of thick-walled glass tubing about 1 cm in diameter is drawn 

 out at one end in the blow-pipe flame to a fine capillary, the dimen- 

 ions of which, in the particular instrument we made use of, will be 



