416 PHYSIOLOGICAL REGULATIONS 



the study of relations is undertaken. Indeed, it is not necessary to 

 recognize whether or not a component is compounded of other ele- 

 ments. A quotient or a subtrahend may be regarded as a combina- 

 tion in this general sense, equally with a multiplicand or any other 

 f(Ji, Jo). A correlative of two or more recognized components 

 sometimes answers the definition of a resultant, and usually of an 

 * ' emergent. ' ' 



Not only may several loads in an organism be considered as a 

 combination, but their simultaneous evaluation constitutes a state- 

 ment of net physiological state. The various modifications thus 

 assess the organism as a whole, as well as they assess individual 

 components. The extent to which this estimate can now be carried 

 is not great; more needs to be known concerning physiological 

 ratios of each component. For certain components, physical and 

 physiological equivalents are established: 1 gm. of water vapor- 

 ized = 0.58 Calories absorbed ; 1 gm. of fat burned = 9 Calories of 

 heat produced ; 1 calorie transformed = < 0.25 calorie of external 

 work. Many other equivalents are more limited in their applica- 

 bility, as their physiological ratios vary of tener with circumstances. 

 The assets of the organism in any two net states have been in fact 

 but very partially compared. 



I believe physiology cannot avoid regarding many combined 

 components as one net component. The emergent of one combi- 

 nation becomes in turn one of several elements in the next combina- 

 tion, and this process may go on indefinitely. Permeability, exci- 

 tation, and respiration are names of such multiple combinations. 

 Or, in a plane or solid figure the manner in which the state of the 

 organism moves hither and yon might be represented. I could use 

 more than three dimensions if I could grasp the simultaneous 

 meaning of more coordinates. Familiarity and practice with such 

 numbers of variables might conceivably cultivate such a grasp. 



In many correlations it is customary and convenient to distin- 

 guish independent variables from dependent ones. The distinction 

 is created by the experimenter or recorder of relations, and, so far 

 as I see, has no counterpart in the organism. Arbitrarily the in- 

 vestigator selects certain conditions for the organism, and for the 

 time being these are described as independent variables. But in 

 another kind of test the organism may select its own quantities of 

 each same variable, in accord with its physiological states. Arbi- 

 trary definitions that are required for the representation of results 



