62 PHYSIOLOGICAL REGULATIONS 



balance rapidly eliminate most of the sodium chloride solution 

 infused; those previously depleted do not. Comparable results 

 follow the infusion of 0.28 M glucose solution in each of the types 

 of depletion. 



The present study is being strictly limited to what occurs after 

 the positive or negative increment of water content has been estab- 

 lished. The additional paths, such as loss by rectal diarrhea, 

 drainage of saliva or nasal secretions or lymph, or loss of blood or 

 sweat, that might be involved in securing the water losses (load- 

 ing), are not concerned in recovery except as the types of load 

 brought about are distinctive of the particular manner of initial 

 loss. 



"With the recognition of many qualitative types of water deficit, 

 the expedient indicated is to designate each type by the procedure 

 used in loading. Before the types are some day quantitatively 

 characterized, the rates of exchange that prevail during recoveries 

 from diverse increments may be measured. 



§ 18. Distinctions among water increments 



Meanwhile how shall I judge when a water deficit exists? In 

 one type of water privation, constant food is being added to the 

 body. In ''dehydration" by sucrose a fluid is added to the blood 

 stream such that more fluid than given is eventually lost from the 

 body. In vomiting, dissolved substances, especially electrolytes, 

 are lost in diverse proportions. In hemorrhage all substances are 

 lost in the proportions present in the blood, but this is not the pro- 

 portion present in the body as a whole. Only arbitrary judgments 

 of what constitutes a deficit are available ; but once a criterion is 

 chosen its consequences are provisionally accepted for purposes of 

 classification and comparison. 



When 0.15 M solution of sodium chloride is infused, the distur- 

 bance of water content is termed an excess (positive load). Is 

 0.30 M also an excess? The answer seems to depend in part on 

 whether the urine subsequently formed is more concentrated or 

 less concentrated than the fluid administered. A systematic study 

 of continuous intravenous infusions (Wolf and Adolph) compares 

 the gains with the outputs of water, after 7 hours during which 

 steady rates of output are gradually attained. With a particular 

 rate of inflow (0.9% of Bo/hour) the outputs become equal to the 

 intakes if the salt concentration infused is either 0.11 M or 0.29 M. 



