50 OBSERVATION OF CIRCULATION. 



the end of the minute. Compare the number of pulsations 

 in the first half-minute with that in the second half. 



4. Stand and take active exercise for a few minutes, as if 

 with dumbbells. Immediately count the pulse. 



5. At home, count the pulse while lying on a lounge, after 

 remaining in that position for half an hour. 



6. Compare the pulse before and after meals. 



7. With the thumb and finger lightly clasp the windpipe, 

 well back. The pulse in the Carotid arteries will be felt. 



Let all the pupils in the class stand. Let one arm hang 

 freely by the side. Hold the other arm straight up as far as 

 the clothing will readily permit. Observe : 



1. The difference in the color of the two hands. 



2. The difference in fulness, both in the feeling of ful- 

 ness and in the prominence of the veins. 



3. The difference in temperature ; place the backs of the 

 hands against the cheeks. 



The position largely determines the amount of blood in 

 the hand, and the amount of blood determines the tempera- 

 ture, the size, and the color. 



With the forefinger stroke one of the veins on the hand or 

 wrist toward the tips of the fingers. The vein swells out. 

 The blood meets resistance in the valves of the vein. Their 

 location may be determined by their bulging out during the 

 experiment. 



Stroke a vein toward the body, and the blood is pushed 

 along without resistance. 



Let the left hand hang by the side. Note the large vein 

 along the thumb side of the wrist. Place the tip of the 

 second finger on this vein just above the base of the thumb. 

 Now, while pressing firmly with the tip of the second finger, 

 let the forefinger, with moderate pressure, stroke the vein up 

 the wrist. It may be seen that the blood is pushed on freely, 



