478 PHYSIOLOGICAL EEGULATIONS 



(2) Exchanges that tend to restore this quantity toward its 

 mean become faster when displacements (loads) occur. 



(3) Net rates of exchange are usually proportional to coinci- 

 dent loads, however diverse the physicochemical kinds of processes 

 concerned in the exchanges. 



(4) Hence a pattern common to regulations is found in the 

 several quantitative investigations of: (a) frequency of occurrence 

 of loads in standard states, (b) rates of exchange in steady states, 

 and (c) rates of exchange in recoveries. 



(5) Upon the precise coordination in the living unit between 

 rate of gain of a component and rate of loss of the same component 

 {e.g., fig. 15) appeared to depend the constancy and accuracy of 

 content of that component. 



(6) Finite durations of load and limited accelerations of ex- 

 changes are implicit in each initiatory, steady, and recovery state. 



(7) Recoveries occur at different rates for each component ; the 

 maximal rates in the same individual differ enormously for diverse 

 components, no matter in what units each is compared. 



(8) Recoveries may be compared as velocity quotients (1/At), 

 which may differ by factors of 10^ among diverse components 

 (table 40). 



(9) The study of each component with respect to either the fre- 

 quency of occurrence, of the rate of exchange as correlated with 

 load, or the environment frequented, characterizes quantitatively 

 one property toward which the organism is self -maintaining. 



(10) The pattern of regulations is not fixed in the individual, 

 but develops during ontogeny, and undergoes various acclimatiza- 

 tions and conditionings. 



§ 180. Retrospect 



To me the study of physiological regulations is as impelling 

 as any other sort of investigation is to others. I have tried to 

 convey that feeling, lest anyone think the inquiry superfluous. 

 Diversity of investigators leads to variety of endeavor, in physi- 

 ology as elsewhere; those who desire to study regulations, sooner 

 or later find suitable means of doing so, other than metaphysical 

 ones. Among these means I envisage numerous further develop- 

 ments and refinements in quantitative description of whatever 

 happenings are related to maintenance and recovery of components 

 in organisms. 



