36 METABOLISM DURING WALKING. 



TECHNIQUE FOR SECURING RECORDS OF THE PULSE-RATE. 



The electrodes in the moist kaolin paste were put in position as pre- 

 viously described, one above the right nipple and the other somewhat 

 lower down on the left side, and fastened in place by means of adhe- 

 sive tape and elastic bandages. The grounding electrode was fas- 

 tened to the body near the umbilicus in a similar manner. The leads 

 were then tested for response and for any fault in the grounding of the 

 subject. At the beginning of the period, a signal was given to the 

 operator in the galvanometer room and within a minute of the begin- 

 ning of the experimental period a photographic pulse-record for ap- 

 proximately 60 seconds was made. In the course of 3 or 5 minutes 

 another record was taken, and a third at about the end of the tenth 

 minute. Thus, during a 12-minute period, three records were ob- 

 tained at approximately regular intervals. To obtain the pulse-rate 

 per minute, the time and pulse-rate were subsequently counted by two 

 assistants independently from these records and the average of the 

 three records was taken as representative of the pulse-rate during the 

 period. If, in any instance, difficulty was experienced in counting 

 the records, or if the two assistants failed to agree in their counts, 

 another count was made by a third individual. In some cases, owing 

 to technical difficulties, it was possible to use only a portion of the 

 record for the final count. 



DETERMINATION OF THE BODY-TEMPERATURE. 



Records of the body-temperature were secured in the rectum by 

 means of an electrical resistance thermometer. The resistance coil em- 

 bedded in Woods metal 1 in a pure-silver tube was provided with leads 10 

 meters long connecting the thermometer with a d'Arsonval galvano- 

 meter and Wheatstone bridge placed in one corner of the room. Two 

 of these rectal thermometers, each having a resistance of about 12 ohms, 

 were used during the study. The apparatus was calibrated at tempera- 

 tures of from 35 to 39 C. at intervals of 0.25 to 0.5 by immersing 

 the thermometer bulb in a Dewar flask. These temperatures were read 

 from a standard Richter mercurial thermometer, with an accuracy of 

 0.01 C. From the points thus obtained, curves were constructed from 

 which temperatures to 0.01 C. were secured. These curves were 

 checked at frequent intervals during the course of the study, to make 

 sure that no change had taken place in the value of the resistance 

 thermometers. 



Before the experiment of the day began, the thermometer was in- 

 serted in the rectum of the subject to a definite depth, with the aid 

 of a slight coating of mucochondrin. The leads were fastened to the 

 buttocks by means of a small piece of adhesive tape to prevent any 

 displacement of the thermometer as the subject walked. They were 



J Riche and Soderstrom, Arch. Intern. Med., 1915, 15, p. 820. 



