226 PHYSIOLOGICAL KEGULATIONS 



'27; Brull, Poverman and Goffart, '36). The most extreme deple- 

 tion is that of chloride, which amounts to over 10 per cent of the 

 body's supposed content of it after water equal to half the body 

 weight has passed through the body during one day (Underbill and 

 Sallick). The depletion of some or all constituents may be more 

 closely related to the modified rates of water output than to the 

 water content of the body at some one time. 



When water excesses are maintained for months very large 

 deficits of chloride possibly result. Wolff ('35) reported that a 

 6.3-kg. dog was depleted of 0.65 equivalent of chloride during 157 

 days of excessive water administration. But I judge, from data of 

 Wier ( '40) that a dog of this size ordinarily contains only one-third 

 that much chloride to begin with; hence Wolff's account of chloride 

 exchanges may have had a systematic error. 



Is there evidence that in water excess constituents are accumu- 

 lated in the body or its parts that are not retained in water balance? 

 In water deficit is there any augmented intake of other substances 

 than water? I know of nothing to show clearly that such occurs, 

 though in the shifts of physiological activities that accompany 

 water loads there may easily be some. 



Fixed tissues sampled during water loads have been analyzed 

 very infrequently for other constituents than water. Significant 

 depletions in electrolyte contents (relative to content of dry ma- 

 terial) of muscle and of skin are demonstrated in water deficit 

 (table 23). If the loss of sodium or of chloride were proportional 

 to that of water, the dilution, which is the ratio of water to electro- 

 lyte (E/Na) would remain constant in the tissue. It appears that 

 no tissue lost an electrolyte in so great proportion as water. In 

 water privation chloride is not lost so extensively from the whole 

 body as from the muscle; hence what chloride may have left the 

 muscle may be in part translocated elsewhere. 



The study of compositions might be a mere exercise in correlat- 

 ing, were there not special questions in mind. The chief one is, has 

 the water-loaded body all its non-aqueous constituents in their 

 usual amounts and places, all ready to soak up the water that will 

 be gained or lost in recovery? For the most part, neither lack nor 

 excess of water greatly upsets the dog's content of any other con- 

 stituent. So there persists a full framework that may serve to 

 indicate when the original water content is restored. 



