242 PHYSIOLOGICAL REGULATIONS 



proportion of the two cations also is modified, sodium becoming a 

 larger fraction of the body's electrolytes. 



These relations may further serve to demonstrate that one con- 

 stituent (water) may not be varied alone. Though water be the 

 only ''intentional" variable, a host of other components automati- 

 cally change their amounts with it, and not in equal proportions. 



Other components (properties) of the body may be measured 

 statically in relation to water content; but few suitable data con- 

 cern them. These are various pressures (vascular, cerebrospinal, 

 intraocular), temperatures (rectal, surface), and plasticities (of 

 eyeballs, skin). Excitability to electrical stimulation through the 

 skin (chronaxie) increases in the first hour after water is ingested 

 (Achelis, '30). No one quantity can at present be said with cer- 

 tainty to be independent of water load. 



(4) Metabolisms. Rates at which diverse processes occur are 

 likewise modified with water contents. 



Oxygen consumption and carbon dioxide production are proba- 

 bly significantly accelerated by water excesses. No regular changes 

 in respiratory quotient have been found. The increases of rate of 

 oxygen consumption precede the augmented rates of v/ater excre- 

 tion (Jarisch and Liljestrand, '27; Lublin, '29; Grollman, '29), 

 and may be concerned rather in the activities of ingestion and 

 absorption and in the excitement of the procedure than in mainte- 

 nance of water contents. Lequime ('40) found no modification of 

 rate of oxygen consumption. 



Rates of volume flow of blood (cardiac output) are likewise said 

 to be increased by an average of 20 per cent. The indirect methods 

 used to measure them (absorption of nitrous oxide or of acetylene), 

 and the variability among paired controls, suggest that some reser- 

 vations be kept about them. Frequencies of heart beat regularly 

 decrease after water ingestion. 



Various types of catabolism have been supposed to be modified 

 by positive water increments, from the facts of faster elimination 

 of nitrogen, phosphorus, urea, or chloride in urine {e.g., Orr, '14). 

 Once these faster eliminations are corrected for the faster water 

 excretions (in the manner shown in table 25), the supposed in- 

 creases in catabolism no longer appear. Unknown factors of 

 analogous sorts may be suspected in almost any process that is 

 being studied. So long as the conclusion is drawn that the rate of 

 nitrogen excretion as measured by analyses of urine, or the absorp- 



