102 ADVANCED LESSONS IN PRACTICAL PHYSIOLOGY 



Open the clamp widely, and pump at the rate of about twelve times 

 in a minute. Effect? 



Determine the respective conditions under which the venous flow 

 becomes intermittent, remittent, and constant. 



Try to discover the causes, in the normal circulation of the blood, 

 of the great difference between the arterial and venous pressures, and 

 the absence of a pulse in the veins. 



B. Intraventricular Pressure. Place a thistle tube against the mem- 

 brane closing the lateral tube of the rubber bulb (ventricle) and con- 

 nect it with a recording drum. Register the changes in pressure occur- 

 ring within the ventricle upon the smoked paper of a slowly revolving 

 kymograph. 



C. Pulse. Place the thistle tube upon the "aorta" and register its 

 pulsations. 



D. Mitral Insufficiency. Remove the rubber sheath from the glass 

 tube representing the mitral valve. This produces a condition analogous 

 to mitral insufficiency. Pump at a normal rate. Observe the effect 

 of this lesion upon the intraventricular pressure, the arterial pressure, 

 the aortic pulse, and the venous discharge. Replace the sheath. 



E. Mitral Stenosis. Tie a thread around the sheath of the mitral 

 valve, thereby restricting the size of this opening. This produces a 

 condition analogous to mitral stenosis. What effects do you notice? 



F. Aortic Insufficiency. Remove the sheath from the semilunar 

 valve, producing thereby a condition analogous to aortic insufficiency. 

 What changes do you observe? Replace the sheath. 



G. Aortic Stenosis. Tie a thread around the sheaiJa of the semilunar 

 valve so that the opening becomes smaller. This condition simulates 

 aortic stenosis. Observe the results. 



