410 STUDIES IN GENERAL PHYSIOLOGY 



minute. This number remained constant until about 9:08. 

 (The current of hydrogen was not as vigorous as usual.) At 

 9: 12 the number of heart-beats was 96; at 9:30 the number 

 was 69; at 10 the number was 48; and at 11 it had fallen to 

 27. At 11:25 the heart beat 23 times per minute; at 11:40 

 it beat 20 times per minute ; after which the number of beats 

 varied between 20 and 23 per minute, until 8:45 P. M.; in 

 other words, more than nine hours. The curve of Fig. 124 

 illustrates the condition of affairs better than description. 

 The curve is typical and may be looked upon as representing 

 any one of these experiments. Only the absolute values 

 varied with different individuals and with the temperature. 



In another experiment the current of hydrogen was turned 

 on at 3:06 A. M. The number of heart-beats was 120. At 

 3:17 the heart beat 126 times, after which the number 

 decreased, as shown in the following table: 



3 : 20 110 beats per minute 



3:22 86(!)" " 



3:25 60 " 



3:27 54 " 



3:31 50 " 



3:34 44 " 



3:40 36 " 



3:45 33 " 



3:52 24 " 



4:00 22 " 



4:05 20 " 



4:12 19 " 



4:20 16 " 



4:30 14 " 



4:55 12 " 



This rate continued unchanged until 9:50, when the 

 experiment was brought to a close. It is readily seen how 

 much more rapidly the decrease occurs at first than later. 

 Fig. 125, which illustrates the beginning of this experiment, 

 shows this very strikingly. 



