ENDOCARUIAC PRESSURE 



IQI 



are communicated to the recording tambour by a long elastic column of air; 

 and fourth, because the tambour arrangement has a tendency to record 

 inertia vibrations. H. D. Rolleston, who has pointed out the above in> 

 perfections of Marey's method, has reinvestigated the subject with a more 

 suitable apparatus. 



The method adopted by Rolleston is as follows: 



A window is made in the chest of an anesthetized and curarized animal, and 

 an appropriately curved glass cannula introduced through an opening in the 

 auricular appendix. The cannula is then passed through the auriculo-ventric- 



FIG. 164. Endocardiac Pressure Curve from the Left Ventricle of the Dog The 

 thorax was opened and a cannula introduced through the apex of the ventricle; the abscissa 

 is the line of atmospheric pressure. G to D represents the ventricular contraction- from 

 D to the next rise at G represents the ventricular diastole. The notch, at the top of 'which 

 is F, is a post-ventricular rise in pressure from below that of the atmosphere and not a 

 presystohc or auricular rise in pressure. 



ular orifice without causing any appreciable regurgitation into the auricle, 

 or it may be introduced into the cavity of the right or left ventricle by an opening 

 made in the apex of the heart. In some experiments the trocar is pushed through 

 the chest wall into the ventricular cavity. His apparatus is filled with a solution 

 of leech extract in 0.75 per cent, saline solution, or with a solution of sodium 

 bicarbonate of specific gravity 1.083. 



FIG. 165. Curve with a Dicrotic Summit from the Left Ventricle; the Abscissa Shows the 



Atmospheric Pressure. 



The animals employed were chiefly dogs. The movement of the column of 

 blood is communicated to the writing lever by means of a vulcanite piston which 

 moves with little friction in a brass tube connected with a glass cannula by means 

 of a short connecting tube. 



When the lower part of the tube, A, is placed in communication with one 



