PHYSIOLOGICAL EEGULATIONS 



443 



§ 159. Measures of regulation 



Qualitative aspects of regulations are of great variety, and a 

 high proportion of current physiological investigation contributes 

 bits of information concerning them. Quantitative measures of 

 what goes on in organisms to secure and ensure uniformity of 

 physiological state appear to be of only three sorts at present, all 

 of which were abundantly illustrated. 



(a) Variability of content of component. In any one of many 

 possible sets of conditions the latitude of loads found is ascer- 

 tained. Some coefficients that have been employed above are; 

 (1) standard deviation and coefficient of variation, {2) root mean 

 square of differences and coefficient of difference, and (5) fre- 

 quency of occurrence. 



TABLE 45 

 Specifications of regulation of water in dog 



(b) Rates of exchange of the component loaded. These may be 

 studied in relation to diverse loads in the form of an equilibration 

 diagram. Or, by abbreviation, various parameters of the ex- 

 changes may be studied, such as: (1) velocity quotient, {2) econ- 

 omy quotient, and (5) augmentation ratio. Provisions for mini- 

 mizing exchanges (resistance to and prevention of them) are 

 prominent. 



(c) Preference for environments that tend to preserve or 

 restore the contents of component. 



Proceeding with specifications in the way an engineer does, a 

 sample appraisal of regulation with respect to one component 

 (water) for one species (dog) would be as shown in table 45. Any 

 single specification indicates something concerning the regularity 

 of the component and of its exchanges ; all of them together make 

 the characterization seem as complete as is allowed by available 



