128 ADVANCED LESSONS IN PRACTICAL PHYSIOLOGY 



the following; scale has been constructed, in accordance with which the 

 vascular tone may be expressed in percentages: 



Heart rate, Systolic blood-pressure, 



increase. . Increase . . Decrease . 



+ 10 +8 +6 +4 + 2 -2 -4 -6 -8 -10 



Oto 4 100 95 90 85 80 75 70 65 60 55 50 



5 to 8 95 90 85 80 75 70 65 60 55 50 45 



9 to 12 90 85 80 75 70 65 60 55 50 45 40 



13 to 16 85 80 75 70 65 60 55 50 45 40 35 



17 to 20 80 75 70 65 60 55 50 45 40 35 30 



21 to 24 75 70 65 60 55 50 45 40 35 30 25 



25 to 28 70 65 60 55 50 45 40 35 30 25 20 



29 to 32 65 60 55 50 45 40 35 30 25 20 15 



33 to 36 60 55 50 45 40 35 30 25 20 15 10 



37 to 40 55 50 45 40 35 30 25 20 15 10 5 



41 to 44 50 45 40 35 30 25 20 15 10 5 



Thus, a person who on standing up shows an increase in the cardiac 

 rate of 10 beats, and an increase in the blood-pressure of 10 mm. Hg ? 

 would be in the condition A (95 per cent.). 



Barach calculates the energy-index in accordance with the following 

 example : 



Pressure. Heart rate. Index. 



In systole 120 mm. Hg X 72 = 8.640 mm. Hg 



In diastole 70 mm. Hg X 72 = 5.040 mm. Hg 



In both 190mm. Hg X 72 = 13.680 mm. Hg 



The highest energy-index in a still normal person has been found to 

 lie close to 20,000 mm. Hg in a minute, and the lowest somewhere 

 about 10,000. 



3. The Effect of Exercise. Determine the normal systolic blood- 

 pressure and rate of the heart with the subject standing;. Repeat these 

 determinations immediately after the subject has made forty flexions 

 and extensions of the arms or thirty knee bendings in one minute. Re- 

 peat one, two, three, four, and five minutes afterward. Construct a 

 curve to show the course of the pressure and cardiac frequency. 



Determine the cardiac frequency and blood-pressure in a subject 

 before and after he has made a stationary run lasting one-half minute. 



Determine the cardiac frequency and blood-pressure in a subject 

 before and after he has ascended forty steps in the course of one minute. 



4. Venous Pressure. Hold the hand against the chest in the region 

 of the heart. Note the degree of filling of the veins. Raise the hand 

 slowly until the veins collapse. Determine the distance between this 

 level and the level of the heart. It corresponds to the height of the 

 column of blood supported by the heart. 



