ENDURANCE OF HUNGER AND THIRST 499 



and Trommsdorf ) more quickly than by the kidneys. An 

 important point determined in these studies is the fact that 

 excretion of creatinin, uric acid, and oxyproteic acids is not 

 influenced in any material degree by protein ingestion. 



Ernest Heilner's observation is of considerable interest 

 in this connection, showing that urea introduced subcutane- 

 ously has a stimulative effect on protein metabolism, thus 

 suggesting the possibility of urea itself being a factor in the 

 special mechanism regulative of the course of intracorporeal 

 protein disintegration. 42 



METABOLISM IN FASTING 



We may now proceed to outline the information we pos- 

 sess relative to metabolism in fasting. 43 It is the author's 

 purpose to set forth only the most interesting points which 

 have appeared in the extensive literature concerning this 

 subject. It has been so often stated that these discussions 

 make no pretense to completeness, that it is decidedly super- 

 fluous to repeat it. 



How Long May Hunger and Thirst Be Endured? 

 What is the longest possible period of endurance of absolute 

 withdrawal of food? The professional faster, Succi, fasted 

 for thirty days ; the American physician, Dr. Tanner, for 

 forty days ; and Merlatti in Paris for as much as fifty days 

 although it must be noted that the last drank water and that 

 Succi took large doses of opium to allay his gastralgia. Adult 

 dogs can be kept alive certainly as much as sixty days in a 

 state of absolute carency. The author would not grant any 

 very great importance to the isolated observation of Kuma- 

 gawa, whose experiment animal died on the ninety-eighth day 



42 E. Heilner (Physiol. Instit., Munich), Zeitschr. f. Biol., 52, 216, 1909. 



^Literature upon Metabolism in Fasting: S. Weber, Ergeb. d. Physiol., 1', 

 701-746, 1902; R. Tigerstedt, Nagel's Handb. d. Physiol., 1, 375-391, 1905; 

 A. Magnus-Levy, Handb. d. Pathol. d. Stoffw., 2d ed., 1, 310-315, 1906; C. von 

 Noorden, ibid., 1, 480-547, 1906; Benedict, Metabolism in Inanition, Carnegie 

 Institution, Washington, 1907; T. Brugsch, H'andb. d. Biochem., 4', 284-306, 

 1908; R. Tigerstedt, ibid., 4", 55-66, 1910; Graham Lusk, Ernahrung u. Stoffw., 

 38-70, 1910. 



