60 PHYSIOLOGICAL KEGULATIONS 



shows. Some of the differences might be due to reliance upon 

 body weight alone as a measure of water deficit in both situations. 

 The recovery from "dehydration" by sucrose infusion may 

 differ from the recovery from the first type of water deficit cited 

 (privation of dietary water, fig. 11) less than many other types do ; 

 there are no suitable measurements of water ingestion after other 

 types. In addition to the types listed in table 3, some that have 

 been termed ' ' dehydrations ' ' in dogs are : privation of food as well 

 as of water (Mayer, '01), hemorrhage (Wettendorff, '01), catharsis 

 by magnesium sulfate (Tobler, '10), pyloric obstruction (Gamble 

 and Ross, '25), intestinal obstruction (Haden and Orr, '23), re- 

 moval of pancreatic juice (Gamble and Mclver, '28), superficial 

 burns (Butler et al., '31), gas poisoning (Underbill, '19), histamine 

 dosage (Underbill and Kapsinow, '22), insulin administration 

 (Drabkin and Shilkret, '27), adrenal insufficiency (Loeb et al., '33), 

 and parathyroid treatment (Shelling et al., '38). While certain 

 features such as decreased body weight or increased concentration 

 of hemoglobin in whole blood may be common to all these states, 

 the danger of having a single term for all the states lies in the 

 prevalent assumption that other characteristics such as water load 

 and water exchange will be uniform. On the contrary, not only 

 qualitative, but particularly quantitative, diversities may be pecu- 

 liar to each type of modification. 



The statement is repeatedly made that ' * dehydration is accom- 

 panied by reduction in the urine flow . . . and by sensation of 

 thirst" Adolph, '33, p. 349; Gregersen, '38, p. 917). A search 

 makes it evident that investigators who produced states of "dehy- 

 dration" in dogs did not heretofore report the rates of urine flow, 

 and no one has yet directly measured the sensation of thirst in 

 dogs. Perhaps the statement is correct sometimes ; but no attempt 

 has been made to limit the term "dehydration" to instances where 

 the reduction and the sensation have been demonstrated. The 

 investigators had, of course, other criteria, either in the blood or 

 in the previous loss of fluid, of the fact that the body had less water 

 than before. The term "dehydration" has many meanings, there- 

 fore, often being not equivalent to "negative water load." No 

 term in previous usage appears to be sufficiently exact to charac- 

 terize an experimental state of water content and exchange. 



A second measure of recovery in negative loads of various types 

 is the retention of injected solutions (fig. 37). Dogs in water 



