REACTIONS OF ANIMALS. Ill 



Erismann, '75). Rubner ('900, 'QO&, 'goc) found that the rate of 

 evaporation was of much importance in connection with the 

 factors pointed out by Reinhard, in determining the metabolism, 

 and general heat regulation economy in men and dogs, and with 

 Cramer ('94) the effect of hair covering and of sunlight upon 

 water loss and heat regulation. Schierbeck ('95) discussed 

 methods of measuring the effect of atmosphere upon organisms. 

 He found that the evaporation varies as the fourth root of the 

 wind velocity. His conclusions regarding the measure of climate 

 have been borne out by later w r orkers: " Bei der Beurtheilung des 

 Einflusses eines Klimas auf die Warmeregulirung des Organismus 

 und bei der Beurtheilung der austrocknenden Wirkung desselben 

 sowohl auf den Organismus als auf leblose Gegenstande ist das 

 Hauptgewicht auf die Geschwindigkeit der Verdampfung zu 

 legen." Wolpert ('98, '99, '020,, and '026) studied the effect of 

 moisture on laborers, the effect of oiling the skin on water loss, 

 the influences of evaporation upon the skin, and the influence 

 of air movement upon water loss and carbon dioxide production. 

 Up to 25 C. the latter was increased; at higher temperatures 

 decreased. Haldane ('05) worked upon the effect of high tem- 

 peratures on man and found that the discomfort was due to 

 a rise in the body temperature. The ill effects were partially 

 prevented if the air was kept moving thus increasing the evapora- 

 tion. Hill ('06) summarizes the important work on the subject 

 of water relations and heat regulation. The heat regulating power 

 of a mouse fails at 24-25 C. (p. 269) in a saturated atmosphere, 

 due to rapid loss of heat, and the animals die from cooling. In man 

 it fails at 29 C. in a saturated atmosphere and if he is active and 

 clothed, he suffers from overheating; at 37 and in the absence 

 of clothing any exertion is practically impossible. In a dry air 

 a man may sit for a time at 100 C. Sutton ('08) states that 

 heat stroke occurs only in a very moist atmosphere (see also 

 Osborne, '10). Aron ('11) working on men and monkeys, found 

 that death from exposure to the tropical sun in the Philippines 

 was not due to any effect of the tropical light (Angstrom, '99; 

 Woodruff, '05; Caskellani and Chalmers, '10), as had commonly 

 been supposed but to an overheating of the body. This could 

 be prevented by shade or by air currents which raised the evapo- 



