UNIFORMITIES AND COMPAEISONS AMONG COMPONENTS 397 



continuous variables: living unit, type of loading, and path of 

 exchange ; and six continuous variables : load, time, rate of ex- 

 change, velocity quotient, change in tissue (volume, dilution, 

 amount) and change in activity (energy transformation, behavior). 

 A useful summary of these variables is their definition, which may 

 now be succinct, together with references to the foregoing use of 

 certain ones. 



Living unit, U, the portion of organisms under actual observa- 

 tion or measurement. 



Component, J, any measurable property of the living unit. 



Content, C, amount of component present in the living unit. 



Load, AC, increment of content; 



Excess, + AC; Deficit, -AC (fig. 110). 



Balance, Co, when C = 0. 



Time, t, hours by the solar clock. 



Rate of exchange, R, rate of transfer or change of component, 

 SC/At. 



Gain, G; Loss, L. 

 Total, net, partitioned. 



Loading, numerical increase of ± AC. 



Recovery = Unloading, numerical decrease of ±: AC. 



Recovery rate, net R during unloading. 



Turnover = Turnover rate, Ro, or R at Co, when L = G. 



Tolerance, sequence of loads. 



Velocity quotient, h, 1/At, R/AC. 



Augmentation ratio, Rm/Ro where R^ is measured total rate, 

 usually maximal or minimal. 



Modification ratio, Rmax./Rmm. 



Economy quotient, G/L. 



Physiological state = State, combination of contents in the liv- 

 ing unit, with emphasis on the one or more contents measured. 



Condition, any environmental situation of U believed to be 

 reproducible. 



Stationary state, any state in which C does not change with time, 

 hence G = L. 



Kinetic equilibrium = Normal, stationary state in which Co and 

 Ro are present. 



Equilibration, group of relations of exchange to content, or rate 

 to load. 



Body mass, B, measured weight or volume of U. 



