OTHER TYPES OF WATER INCREMENT 67 



elimination of the excess follows introduction by stomach. A 

 whole circulatory system and at least one intact kidney are re- 

 quired. The kidney need not be innervated, nor need any adrenal 

 be present. For polyposia to follow, deficit is created in the pres- 

 ence of intact swallowing machinery, but no one group of cranial 

 nerves need be intact. The esophagus may be disconnected from 

 the remainder of the alimentary tract. Some day all that informa- 

 tion may possibly be arranged so as to explain water regulations 

 to students of physiology. At the present time it seems to form 

 little but a special paragraph in the anatomical story of the dog. 



The diversities of water exchanges sho\\Ti among the types of 

 load-production that have been cited (tables 3 and 4) are : (1) Rates 

 of both intake and output sometimes are increased during recov- 

 eries (sucrose, sodium chloride). (2) Rates of both may be de- 

 creased, thus preventing recovery (luminal, ethyl ether). (5) 

 Water excesses may be temporarily retained, with less rates of out- 

 put than are shown after introduction of water by stomach to 

 control individuals. (4) Polyuria may appear only after a delay 

 of some hours, or (5) polyuria may disappear before the positive 

 load of water has been completely returned. 



The exact evaluation of the statistical significances of the diver- 

 sities awaits further data. Physiological classification of the types 

 of load might be based on the rates of exchange or the velocity 

 quotients that result, thus minimizing the emphasis upon agents 

 and conditions that prevail. 



What are the uniformities found among all the types of water 

 load that have been mentioned? (1) Some change occurs either of 

 absolute water content (ml. per 100 gm. wet weight) or of relative 

 water content (ml. per gm. dry weight, or weight of some com- 

 ponent). But the relative content may differ in sign as well as in 

 magnitude from the absolute content. (2) Rates of water ex- 

 change are modified with load. (3) Other uniformities are con- 

 cerned with quantities outside of water exchanges and water con- 

 tents of the whole body. (4) The fact that some features such as 

 increased rates of urinary loss are common to several types of 

 water increment is no guarantee that other features such as rates 

 of salivation will also appear common. (5) Many possible rela- 

 tions of water in the body do not occur in water loads of any sort. 

 Some of these are : increased rates by paths other than ingestive, 

 urinary or salivary; increased rates of ingestion in relative water 

 excess ; augmentation in rate of loss without any lag. 



