124 



PHYSIOLOGICAL EEGULATIONS 



they are little greater than at AW + 5 (data of Frey, '07). Ex- 

 treme water excesses are established niore readily in this species 

 than in dog because vomiting does not occur. 



In deficits, attained after privation of water but not of food, the 

 rabbit recovers its body weight in a few minutes of drinking (fig. 

 73), taking, on the average, amounts slightly greater than the initial 

 loads (fig. 74). That would not have been surmised from earlier 

 studies of Pack ('23); for in his tests the rabbits, deprived for 

 several days of food as well as of water, ingested in 0.5 hour even 

 less water, relative to body weight and to water load, than did men 

 (§29). 



0.4 0.8 1.0 



Hour 



Fig. 73. Course of water load measured by water consumed (% of Bo) during 

 recovery from water deficit in rabbit. In each of 10 tests one of two individuals has 

 been deprived of water but allowed food for 24 hours before zero time, when water is 

 freely offered. Bars indicate standard errors of total amounts of water ingested. Dash 

 line indicates mean water consumed in 12 control tests at same time of day in which 

 water but not food is allowed ad libitum without previous privation. New data. 



Turnover of water has been ascertained as 13% of Bq in 24-hour 

 periods (Gompel et at., '36; Gasnier and Mayer, '37). Most of the 

 water is contained in the (green vegetable) food ordinarily eaten. 

 On dry food (oats) plus water ad libitum, turnover is consider- 

 ably less (7.0% of Bo/24 hours; new data). 



Variability of water intake in 24-hour periods is in a selected 

 instance (HI of Gompel et at., '36) smaller than has been reported 



