CORRELATIVES OF WATER CONTENT AND EXCHANGES 



275 



of ontogenetic physiology and of comparative physiology of water 

 exchanges. Size and age are convenient correlatives of rates of 

 exchange, for each brings all its other correlatives into the picture. 

 Clearly, at birth equilibration of water content is not, in dog or 

 man, of adult dimensions; it is transformed later into the recog- 

 nized pattern of the adult. Regressions of size with rates of water 

 exchanges in turnover and in maximal compensations, both total 



1.2 



a; 0.8 

 u 

 _o 

 o 



ZJ 

 D. 



O0.4 



S- 

 01 



-p 



o 

 £ 



+■ 



o 



2 4 6 



Log Gm. Body Welgh-fc (B) 



Fig. 142. Partition of rates of water output by paths, for various species of mam- 

 mals, relative to rates of energy transformation. Each species is represented at its 

 body weight. Total output (turnover) is taken as equal to the total intake of figure 

 141. Partition is relative to the total water loss, as listed in table 16 and in additional 

 data of Benedict ('38). 



and partitioned, turn out to have the same sorts of significance as 

 regressions of size and age with energy exchanges. Many data fit 

 allometric equations of relative magnitudes. Presence or absence 

 of internal convection, and types of metabolism of nitrogen, energy, 

 and roughage, are partial correlatives that may be distinguished 

 in the relations of water exchanges among species. 



<§i 97. Temperature 



Are the water exchanges as measured also influenced by body 

 temperatures that prevailed? In ''warm-blooded" animals, in- 

 creases of body temperature above the usual are accompanied by 

 enormous increases of rates of total water exchange. Considera- 



