PULSE-RATE. 



395 



The tracings for the two days from the standard leads designated 

 L^ L^, and L^ are shown in table 83 as pulse-rates per minute. These range 

 from 35 to 54; in the case of every subject lower pulse-rates were found 

 at some other time during the investigation. This would naturally be 

 expected. The subjects were thoroughly accustomed to having the 

 pulse counted at the wrist, but this was not the case with the electro- 

 cardiographic tracings. Furthermore, both of the dates, December 20 

 and February 2, came at the end of a period of weight maintenance, 

 during which time the amount of food was somewhat larger than at 

 other periods. Since there was a noticeable correlation between the 

 height of the pulse-rate and the energy 

 intake, it could not be expected that 

 the pulse would be as low here as it 

 was, for example, at the middle of 

 November. Nevertheless, the pulse- 

 rates in the tracings which were made 

 are mostly on a definitely lower plane 

 than is commonly accepted as the 

 normal pulse-rate for men of this age. 

 The records taken in the chamber 

 before the men got out of bed show 

 especially slow rates, being 35 to 38 

 for the three men, Kon, Pea, and 

 Pec. 



If there were any pathological con- 

 ditions to be found in the electro- 

 cardiographic tracings with the subjects on whom we took records in 

 this low diet investigation, we would deem it necessary as important 

 data of the experiment to pubUsh all the tracings. Several of the 

 tracings with explanatory legends are presented in figures 88, 89, and 

 90. In selecting the illustrations our only preference was to show 

 those tracings which demonstrated the slower pulse-rates. Only nor- 

 mal electrocardiograms were shown by all of the subjects in every lead. 



The usual chief deflections, P, R, and T, are present in their normal 

 sequence and with no appreciably altered time relations. The waves 

 are regular and of usual amplitude, and in no case is any certain wave 

 absent or present in excessive number, that is, there are no extra 

 systoles. Inhere is no pathological arrhythmia, and absolutely no indi- 

 cation of heart block. Thus it is certain that the standard electro- 

 cardiograms demonstrate no abnormality other than the slow rate. 

 The condition would appear to be classifiable as a sinus Bradycardia. 

 This condition of slow, regular pulse-rate is known to occur normally in 

 convalescence, old age, and pregnancy. These standard electro- 

 cardiograms taken in connection with our research seem to demon- 

 strate that sinus Bradycardia may also normally occur with a lowered 



