inteoduction 11 



§ 5. Outline of the investigation" 



The plan of this investigation is the equivalent of an inter- 

 weaving of at least five studies. Each of them could be under- 

 taken separately, but their interplay multiplies the inductions that 

 can be formulated from the data presented. 



(1) Water exchanges in animals. 



(2) Rates (kinetics) of certain classes of physiological proc- 

 esses ; time sequences. 



(3) Quantitative comparison of like functions in diverse spe- 

 cies and individuals. 



(4) Organ and tissue exchanges; the study of specializations, 

 localizations, paths, and routes. 



(5) Components (constituents, endowments, and properties) ; 

 similarities and contrasts in their metabolisms and econo- 

 mies. 



Emphasis throughout is upon interrelations among simultane- 

 ously occurring activities. 



Some features into which this study delves, incidentally to its 

 chief purpose of describing physiological regulations, are : 



Water metabolism of man (chapter V) 



Tolerance curves (§ 71 and § 133) 



Stationary states in organisms (§ 138) 



Variabilities of organisms (chapter IV, and § 131) 



Recovery processes (§ 71 and '^ 133) 



Signs of disturbance and disease (§ 162) 



Interacting maintenances (chapter XVII) 



Temperature regulations (chapter XIV) 



Selection of environments (§ 43 and ■§ 132) 



Storage and depots (§79) 



Ontogeny of regulatory processes (§ 96 and § 115) 



Comparative physiology (§ 107 and § 141) 



Cells and tissues as regulated units (chapter VIII) 



Volumes of distribution (§ 58 and § 80) 



Blood volumes (§ 59 and § 80) 



In designing the investigation, it is useful to distinguish certain 

 categories of measurement with which the data will deal. The 

 variables initially selected for study fall into six classes, none of 

 which excludes from membership in other classes : 



