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SOME SPECULATIONS CONCEKNING REGULATIONS 469 



(13) Theory of substitution. "Free" existence, to use Ber- 

 nard's term, is attained in the course of evolution by the substitu- 

 tion of compensations for preservative behaviors alone. Regula- 

 tions by compensations allow the organism to occupy environments 

 that otherwise would limit its range. 



Postulates of the sorts suggested may be multiplied indefinitely. 

 The phenomena upon which they rest are the everyday observa- 

 tions of physiologists. The isolated facts mean little individually, 

 but in selected correlations can mean much. Limitations in physi- 

 ology are probably both in producing fertile suggestions of rela- 

 tionship, and in critically amassing data from which each relation- 

 ship may at long last be induced. 



Had any of these broad theorems been substituted for the 

 limited inductions previously made, the outcome of the investiga- 

 tion would have far surpassed the scope of the materials studied. 

 It might have been implied that, in place of dog B, '^ protoplasm" 

 was studied; in place of heat, "physical quantities"; in place of 

 equilibrations or correlations, "vital organization." The use of 

 general terms is only by inference a substitute for the use of enough 

 data to see what the varieties as well as the uniformities in their 

 relations may be. Where special physiology ends, and how general 

 is general physiology, are matters of opinion and arbitrary defi- 

 nition. 



§ 173. SUMMAET 



Speculations that are related to the physiological phenomena 

 above investigated, propose specific inquiries, such as: (a) a frog 

 ought to drink fast after water denial (§ 37), (b) aglomerular kid- 

 neys must be incapable of water diuresis (toadfish, figure 122a), 

 (c) maybe a dog does not waste injected sugar until his stores are 

 full (fig. 209), (d) I guess a man will be able to excrete urine faster 

 than to excrete sweat. Each speculation frames a question that 

 can be answered by test ; definite queries were asked in profusion 

 before and during the course of the investigation, and nearly all of 

 them have been withheld from the record. All are framed so that 

 if state Zi is substituted for state Iq, and i is measured before and 

 after the substitution, a quantitative answer is found. 



Other speculations are non-specific. They have the form: 

 physiological state I is related to factors (components) J, K, L, etc., 

 while factors M, N, 0, etc. may be ignored. Very often factor J 



