WATER EELATIONS OF FROG 



115 



load, whereas the quotient for total intake (not shown) is propor- 

 tional to reciprocal of load. 



Initial velocity quotients at small net rates of water exchange 

 exceed those at large net rates (fig. 69). As, later in the same tests, 

 the rates become smaller, the quotients remain significantly differ- 

 ent (fig. 70). Hence the individual courses of recovery do not 

 exactly recapitulate the array of initial recoveries at identical 

 diverse loads. 



A few of the data shown for frogs are confirmed by independent 

 measurements ; after desiccation by data of Durig ( '01) and Adolph 

 ('32), and after water injection by sparse observations of Adolph 

 ('27). 



0.6 



^ 0.6 



•i 



^ O.d 



+> 



:> 



02 





0.5 



1.0 



1.5 



a.Q 



2.5 



Hours 



Fig. 70. Velocity quotient (1/hour) in relation to time. Each point is referred 

 to the middle of the period during which it prevailed. Each curve represents a group 

 of 10 individuals starting with the water load indicated. From figure 65. 



A biologist unfamiliar with amphibia might expect a frog to 

 gulp water by mouth after being highly desiccated, especially if 

 water is made available to the tongue but not to the skin. Water 

 is not ingested or swallowed. Dogs and men use the quick oral 

 means of obtaining water, but frogs are constituted to sit patiently 

 in water long enough for water to penetrate the skin. No cry of 

 inaptitude in the frog's behavior would help investigators to ascer- 

 tain whether or not the frog has maximal fitness in its water ex- 

 changes ; swallowing of water on the part of an animal that has no 

 way of metering it might be more damaging than appropriate. 



The accuracy of recovery of water content is indicated by the 



