426 PHYSIOLOGICAL KEGULATIONS 



ascertained. So it is possible (a) to induce general relations and 

 (b) to distinguish and classify peculiar characteristics of living 

 units and of environments. Definition and classification are giant 

 sieves by which it is possible to cull out uniformities and differ- 

 ences. 



(5) The correlations examined lead to certain broader induc- 

 tions that are rigorously derived ; ' ' Induction is demonstration by 

 recurrence," said Poincare ('13, p. 40). Many physiologists ex- 

 press mild interest in having syntheses among grouped facts carried 

 out in their science, but think it impractical to do so by exact 

 methods. I believe that the methods used here and elsewhere 

 are capable of great rigor and extension ; that sound and accurate 

 synthesis by quantitative description has been demonstrated. 

 Nothing spurious is added to the facts through exploration of any 

 number of relations, in so far as the language used is descriptive. 



(6) Choices of variable in further researches are facilitated by 

 the conceptual scheme used here, as by any other. The multiple 

 relations of each variable are already explicit. New observations 

 are classified, and patterns of relation to other variables are 

 suggested. 



(7) From the conclusion that enormous numbers of factors in 

 an organism are interrelated, two corollaries follow : (a) The num- 

 ber of physiological studies of two variables at a time is almost 

 infinite, (b) Most such studies show positive or negative correla- 

 tions, not zero correlations. This expresses the enormous "fruit- 

 fulness" of physiological research, since its '^ success" is widely 

 taken to depend on finding positive or negative correlations. I 

 believe it is misleading to suppose that there is anything unique 

 in the correlations found, or that one choice of variables was any 

 cleverer than other possible choices ; or to intimate there is not a 

 semi-infinite number of other relations just as meaningful if they 

 had been described instead, whether found by help of or without 

 help of a plausible hypothesis. To that statement much exception 

 will be taken, and it remains to be ascertained whether the relations 

 that have been recorded in a century, concerning water in mam- 

 mals, for instance, are more informing to a beginning student than 

 an equal number of relations that were not recorded. 



In a sentence, the general procedures that may be of use in any 

 physiological investigation consist in : finding many correlatives of 

 one or few variables, developing methods of recording relations, 



