532 



Messrs. M. Flack, L. Hill, and J. McQueen. 



containing the tissue schema, the results were as follows, when the compression 

 was arranged to produce a maximal pulsation. When the chamber was closed 

 at the moment of diastole the artery became fixed in diastole and remained 

 flat, so that the pulse scarcely came through (fig. 17, A). Closing the outlet 

 now restored both pressure and pulse, for as the flow was thus completely 

 stopped the artery distended. On the other hand, when the chamber was 

 closed at the height of systole the artery was fixed fully open and the pulse 

 came through, but with a diminished diastolic excursion (fig. 17, B). 



Experiment X. 



The artery and vein were in one compression chamber, the kidney in 

 another separate chamber. The flow was from artery to kidney to vein. 

 The compression chambers were connected with each other and to the 

 manometer. 



A. The compression chamber of the artery was closed. On compressing 

 the kidney alone the kidney shrank, and the pulse of the renal arteries became 

 at first more ample owing to lessened lability of the kidney vessels. Finally, 

 the outflow almost stopped owing to the resistance in the kidney, and the 

 renal artery, becoming distended, ceased to pulse. On now compressing the 

 artery and vein in their chamber to a like amount the resistance increased 

 in the vein, and the kidney expanded so that the pulse and flow began again. 

 It took a much higher degree of compression applied simultaneously to 

 artery, kidney, and vein to stop the pulse and flow. 



B. The compression chamber of the kidney was closed. The artery and 

 vein were compressed alone. The vein was flattened and the flow ceased, 

 the artery becoming distended, and the systolic force spent in expanding the 

 labile kidney. On now compressing the kidney, this organ shrank and 

 became less labile (more rigid), and the pulse and flow began again. 



Experiment XI. 



The flow is through (1) artery, (2) kidney. Each is placed in a separate 

 compression chamber. These chambers are connected together. The tube 

 connecting artery and kidney is joined to the manometer. 



A. The compression is increased in both chambers. The kidney shrinks, 

 the pressure rises, and a maximal pulse of the arteries develops ; as the 

 pressure is made greater the flow and pulse cease. On decompression the 

 maximal pulse occurs at a lower level than on compression (fig. 18). 



B. The tube leading to the compression chamber of the artery is closed 

 and the artery thus made rigid. The pulse transmitted to the manometer 

 becomes ampler, because it is no longer damped down in its passage through 



