488 Influence of Inanition on Metabolism. 



The arterial tension as well as pulse rate per minute are important factors 

 in estimating the work of circulation, but unfortunately all attempts to 

 measure accurately the blood pressure in these experiments failed. 164 



It is much to be regretted that in the longer experiments, which are of the 

 greatest value for comparing the variations in the total heat production with 

 the external and internal muscular activity, the records of pulse rate are 

 defective. Furthermore, no records of the rate of respiration were obtained. 

 A comparison, however, of the pulse rate and the total heat production is of 

 in I crest. The subject of experiment No. 75, S. A. B., recorded the pulse with 

 considerable regularity during the day. The first record was made in the 

 morning, not far from 7 h 30 m a. m., and was undoubtedly influenced by the 

 muscular activity attendant upon rising, weighing himself and his chair, bed- 

 ding, etc. As an inspection of the data on page 170 shows, his pulse exhibits 

 considerable irregularities from day to day during the period. By omitting 

 this first observation and averaging the remainder during the fasting period, 

 a rough approximation of the average pulse rate per day can be obtained. 



A comparison (see p. 509) of this pulse rate with the total heat production 

 shows a striking uniformity in fluctuations, and similar comparisons with other 

 experiments show in nearly every instance a parallelism. 



The pulse rates in the 2-day fasting experiments have been tabulated, 

 together with the respiration rate and total heat production. Although the 

 pneumograph method of obtaining pulse rate and respiration was, on the whole, 

 extremely satisfactory, there were a number of days when the observations 

 were more or less irregular and hence difficulties were experienced in obtaining 

 a fair average pulse and respiration rate for each period. An examination of 

 the detailed statistics for the experiments will show the data from which the 

 averages recorded in table 235 were obtained. 



Examination of the table shows that in general there is a very marked 

 regularity in the results of pulse rate, respiration rate, and total heat produc- 

 tion when they are compared. But there are a few striking anomalies. Per- 

 haps the most noticeable is in experiment No. 81, where the pulse rate and 

 respiration rate for the second period both increased on the second day, and yet 

 the total heat production decreased nearly 80 calories. 



In the decade in which experiments have been in progress in this laboratory, 

 evidence has been accumulating to correlate the minor muscular activity with 

 heat production, and the experience thus obtained has been utilized in esti- 

 mating the visible muscular activity in terms of calories recorded in table 234. 

 But it is obvious that careful measurements of pulse rate are of the greatest 

 importance in obtaining an estimate of variations in the so-called internal 

 muscular work. During " rest " experiments this factor evidently varies more 

 than does the visible external muscular activity. 



M Cathcart (Biochemische Zeitschrift (1907), 6, p. 109), finds that blood-pressure 

 as well as pulse-rate decreases during inanition. 



