LABORATORY MANUAL OF PHYSIOLOGY. 



leather, the base being made of vulcanite or wood and perforated 

 for the entrance of the inlet tube. The top consists of a light 

 aluminum frame covered with paper. The sides are made of 

 peritoneal membrane, varnished with a dilute solution of boiled 

 linseed oil to make them airtight. 1 



Place the kidney in the oncometer, cover the exposed abdominal 

 viscera with the warm cotton pads moistened with physiological 

 salt solution, and arrange the recording apparatus for writing on 

 a medium slow drum. Arrange the recorder for urine flow under 

 the kidney-volume recorder. The urine should also be collected 

 for examination, later. Be careful that the ureter, the renal artery, 

 and renal vein are not obstructed by kinks. Keep the ureter from 

 drying by moistening, from time to time, with physiological salt 

 solution. 



Observe and record the changes in kidney volume and urine 

 flow for a period of twenty minutes or one-half hour. Is the rate 

 of urine flow constant during this time? Are there any changes 

 in the volume of the kidney? How do urine flow and kidney 

 volume correspond? 



3. Blood Pressure and Kidney Volume. Expose the carotid 

 artery, vagus nerve, depressor nerve, and jugular vein. Introduce 

 cannulae into the artery and vein. Pass thread loops around the 

 nerves for convenience in handling. Connect the artery with the 

 mercury manometer. Record blood pressure on the same drum 

 used for recording kidney volume and urine flow. Note the cor- 

 respondence between the changes in blood pressure and changes 

 in kidney volume. 



(a) Divide one vagus nerve. Stimulate the peripheral end with 

 a tetanizing current sufficiently strong to cause inhibition of the 

 heart-beat. Note the effect upon the volume of the kidney. 



(b) Allow the blood pressure to recover from the effect of the 

 vagus stimulation. Now stimulate the depressor nerve with a 

 medium strong tetanizing current until a marked depressor effect 

 is obtained. Note the effect on kidney volume and urine flow. 



1 For further details see Journal of Physiology, vol. xxvii., p. 473. 

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