394 PHYSIOLOGICAL EEGULATIONS 



cies, extends the field of work. Anyone may derive new views and 

 concepts in comparative physiology by listing the accuracies of 

 regulation (variability of content), or the modifications of ex- 

 change, of some component in several species. 



§ 142. Equilibration diagrams 



Having found equilibration diagrams of great use in represent- 

 ing what is known of regulations by compensation, I summarize 

 their characteristics. They are constructed as follows : 



(a) The increments of content were ascertained for some com- 

 ponent in a living unit. These increments were termed loads (AC). 



(b) The content of the component in the same or another indi- 

 vidual in a control state was taken as zero load (Co). 



(c) The rates of gain and of loss (oC/At) of the same com- 

 ponent were ascertained at diverse loads. 



(d) The units employed in measuring C were either sensibly 

 identical or believed similar in loads (AC) and in rates (SC/At) of 

 one component. 



(e) When rates were proportioned to loads, velocity quotients 

 (1/At) were obtained that were independent of the dimensions of C. 



(f ) The diagram correlating rates with loads was constructed 

 in a uniform fashion for several chemical constituents, energies, 

 forces, and frequencies of diverse organisms. 



(g) Quantitative comparisons were facilitated among many 

 components with respect to the relative rates and velocity quotients 

 found. 



The generalized equilibration diagram (fig. 110) has the follow- 

 ing features : 



(h) G (gain) > L (loss) whenever AC is negative, and L > G 

 whenever AC is positive. Each is of a nature that tends to restore 

 AC to zero. 



(i) At balance G = L. This is found to occur in those states 

 that were chosen as controls or zero loads. 



(j) At other loads than zero, either G has another magnitude, 

 or L has another magnitude, or both. 



(k) The rate of net exchange increases as load increases. 



(1) The slopes (1/At) of the lines correlating net rates with 

 loads near the zero load, measure the velocity with which any small 

 load that accumulates is again lost from the organism. 



(m) The equilibration diagram represents a symmetry of proc- 



