CHARACTER OF KATABOLISM 91 
in all of the experiments if the last quotient in the preceding rest-period is 
taken as a base-line. Thus the quotient changes on March 19 from 0.87 to 
0.91, on March 25 from 0.95 to 0.97, on March 27 from 0.87 to 0.97, and on 
March 28 from 0.80 to 0.86. 
An experiment with M. A. ML, not included in this table, that of Feb- 
ruary 16, 1912, differs somewhat from the others inasmuch as there were two 
consecutive periods of rest, with respiratory quotients of 0.86 and 0.85 re- 
spectively, then two periods of work with quotients indicating the usual rise 
after rest, namely, 0.90 and 0.94 respectively, next seven periods of rest with 
quotients of 0.70, 0.77, 0.77, 0.73, 0.76, 0.79, 0.79, followed by one period of 
work with a quotient of 0.81, and finally two periods of rest with quotients of 
0.74 and 0.79. Although the mathematical differences between the quotients 
are not as great as in some of the experiments already cited, these results 
likewise substantiate the general impression that the respiratory quotient 
increases with work and subsequently decreases after the work is over, again 
increases slightly when the work is resumed, and in turn decreases during the 
following rest -period. 
INFLUENCE UPON RESPIRATORY QUOTIENT OF VARIATIONS IN AMOUNT OF WORK DONE. 
For the specific purpose of studying the influence of an alteration in the 
load upon the muscular activity and the efficiency of the body as a machine, 
a lengthy series of experiments was carried out in which the subject began 
with a very light resistance which was subsequently increased materially. 
Certain experiments reversed this routine, the periods with the heavy load 
preceding those with the light load; finally two experiments were made in 
which the light load was first used, then the heavy load, and subsequently 
the light load was again used. The respiratory quotients for these experi- 
ments have been computed and presented in tables 97, 98, and 99. 
The results of the experiments in which a small or moderate amount of 
work preceded the severe work are given in table 97. The striking feature 
of these results is the fact that the quotients for all the individual periods in 
which severe muscular work was done are high with the exception of one 
period in the experiments of April 3, March 16, March 12, and March 13, 
respectively. All the other quotients were 0.87 or higher, with an average 
of over 0.91. Only four of the experiments permit a comparison of the results 
obtained with 0.5 calorie per minute and 1.65 calories per minute, and these 
show no definite relationships one way or the other, the average quotients in 
both series remaining about the same. Obviously, since the resting value was 
not obtained with these experiments, the first respiratory quotients on indi- 
vidual days may be considerably affected by the character of the preceding 
diet, and the evidence does not justify any definite conclusions. The only 
deduction warranted by the data, therefore, is that in general in all periods 
with excessive muscular work the respiratory quotient is high. 
In discussing the data given in table 97, the experiment of March 15 
demands special consideration. On this date the subject rode with a high 
intensity, namely, 1.95 calories of external muscular work per minute, for a 
long period, the object of the experiment being to produce fatigue and com- 
plete exhaustion. From the accumulated muscular work, which is given in 
the light-face figures, it will be seen that the subject on this day did 489 
