INTERRELATIONS AMONG COMPONENTS 407 



the maximal loads present in each are brought to a common scale. 

 But the decelerations are probably significantly diverse ; upon the 

 superimposed scales the deceleration of oxygen consumption is 

 greatest and of heart frequency is least. 



Altogether, 6 variables are represented in figure 185, and simul- 

 taneous points of all 6 may be found connected by light dash lines. 

 Among varying numbers of variables from 2 to 6 at one time, the 

 total number of combinations is 57; or among 2 at a time is 15. 

 Whatever features are evident now that were not noticed in figure 

 176, are brought out solely by the transformations of coordinates. 



Many other quantities have been studied during and after phys- 

 ical exercise. Indeed, the same tests that have just been analyzed 

 furnish data for systolic and diastolic arterial pressures (fig. 176). 

 Each of these is very different from the other 3 components; for 

 both show negative loads at some portion of the test ; and none of 

 the 7 additional bicorrelations of each with other single loads forms 

 a line having a narrow loop resembling X or W. 



When other data concerning physical exercise are examined, the 

 conditions and states and individuals concerned are, of course, dif- 

 ferent from the above. Selecting two familiar components whose 

 rates of change contrast greatly, I correlate heat loads with simul- 

 taneous values of heart frequencies, using data of Christensen 

 ('31). Two rates of work are represented in figure 186. In S a 

 stationary state with respect to heart frequency is maintained dur- 

 ing the interval from 0.2 to 1.0 hours after work began, but not 

 with respect to rectal temperature or to heat load. In R, what 

 looked at first (0.1 to 0,5 hr.) like a stationary state of heart fre- 

 quency, later proved distinctly unsteady. Both tests show approxi- 

 mately rectangular loops correlating the two loads, two of the four 

 corners being at the start and the stop of exercise. A partial 

 diagram of this variety was used by Dill et al. ('31, p. 512). The 

 rates of loading and unloading contrast sharply for the two com- 

 ponents. But each rate follows a similar course in loading and 

 in unloading. Heart frequency augments and diminishes suddenly 

 at start and stop, so that most of its transition and its recovery is 

 completed in 0.05 hour. Heat load changes almost uniformly with 

 time throughout the test, requiring about as long for its recovery 

 as for its loading, and never reaching a stationary state. 



All the components that have been studied in chapter XV, ex- 

 cept those of tissue replacement, have been at some time or other 



