Pulse and Respiration. 105 



Immediately after the tetanus they separate and maintain their respec- 

 tive levels throughout the period of recuperation. In examining these 

 two curves for period 1 it should be remembered that the terms alcohol 

 and normal are purely arbitrary and used simply for convenience in 

 designating the two groups of days. In reality each curve represents 

 values as normal as the other, as both represent data obtained during 

 the first experimental hour before either the control or the alcohol 

 dose had been given. 



No complete explanation is at hand for the fact that the two curves 

 followed a nearly identical course during pre-tetanus and tetanus and 

 then changed to such definitely different levels in the process of recu- 

 peration. Before such phenomena can be properly discussed, doubt- 

 less much more normal data must be obtained. The physical exercise 

 which was chosen in this measurement to act as the stimulation to 

 heart rate is not one that is susceptible of careful standardization. 

 The chief thing which recommended it was the rapidity with which rest, 

 muscular tension, and relaxation could follow each other. The transi- 

 tional interval from rest to tension would naturally be much longer if 

 the subject were required to rise, stand, and then perform genuflections 

 or other vigorous movements; the transition to relaxation would also 

 be lengthened. While voluntary stiffening of the muscles of limbs and 

 trunk at a given signal is ideal from the standpoint of a quick transition 

 from rest to activity, and then to rest, the intensity of activity or mus- 

 cle tension is largely dependent upon the subject. The instruction to 

 "be vigorous " avails, of course, only in a general way and does not pro- 

 duce uniformity. The experimenter did not observe with certainty 

 that the tetanus was more vigorous on certain days than on others, but 

 noted that it tended to decrease somewhat from second to second during 

 the short interval which was used. There were times when the subject 

 seemed to make a fresh effort during the last one or two seconds of the 

 interval as if he himself recognized that he had relaxed his muscles. 

 Some slight indication of the vigor of tetanus is provided in the action- 

 current curves which are shown along with the electro-cardiograms. 

 These can be clearly seen in figure 11, A and B, and are usually fairly 

 prominent. Later trials with this same measurement on another sub- 

 ject, however, have shown that the pulse-rate in the post-tetanus part 

 of a record is largely influenced by the vigor of the muscle tension dur- 

 ing the 5-second interval. If the tension is very vigorous the rate in 

 the recuperation period will reach a point equaling or surpassing that 

 during the tetanus; that is, the condition will be just the same as was 

 found for Subject VI in the pre-alcohol periods of the alcohol days. 

 It thus appears probable that the subject, guessing that alcohol was to 

 be given, was incited by the fact to more severe effort. That he should 

 be more vigorous on July 4 is only to be expected from the general spurt 

 which obtained on that day. 



