8 14 ANIMAL HEAT. 



the depth of winter to the height of summer ; in the month of February 

 the mean temperature was 40'8, in April 42, and in July 43 0> 77 ; from 

 this time the temperature hegan to decline. It was also found that, in 

 winter, birds could more readily resist the action of extreme cold than 

 in summer. 



Davy 1 observed the temperature of sheep during summer and 

 winter, and his results, although they are not sufficiently consistent 

 for positive conclusions, seem to show that the temperature of the body 

 is a little higher in the warm weather than in the cold. 



The influence of extreme heat and cold. The experience of 

 the inhabitants of tropical climates shows that it is possible to live even 

 in an atmosphere the temperature of which at times exceeds that of the 

 body, and that the body is able, by "means of the cooling effect of the 

 evaporation of sweat, to prevent its temperature rising a degree above 

 the normal. 



Lining, 2 in 1738, found that the temperature of his axilla was 36'l, 

 and that of his mouth 36'7, when the heat in the sun's rays was 511, 

 in the shade 367, on a hot summer's day in South Carolina. Ellis, 3 in 

 1758, observed that the temperature of his body was not above 36 *1 

 when he was living in Georgia, and the temperature of the air was 

 40 '6. Experiments on men and on lower animals have shown that much 

 greater heat can be borne for short periods. Blagden and Fordyce 4 

 observed their own temperatures after remaining in heated rooms, and 

 found that the effect varied according to the amount of moisture 

 present ; thus, after remaining fifteen minutes in a damp room heated 

 to 54 - 4, the temperature of the mouth and urine was 37'S, but a 

 similar exposure in a dry room heated to 115 0> 5 126 *7, and in which 

 beefsteaks were being cooked by the heat of the air, did not raise the 

 temperature of the body above the normal. Similar experiments were 

 made by Dobson, 5 who found that the temperature in the mouth of one 

 man rose to 37*5 after he had remained about fifteen minutes in a 

 room heated to 94 0- 4; in another case the rise was to 38'6, after 

 twenty minutes' exposure to air at 98 '9 ; and in a third case a stay of 

 ten minutes in a room at 106*7 caused a rise to 38 '9. 



Tillet 6 had previously observed young girls remain without 

 any inconvenience for five or ten minutes in a kiln heated to about 

 130, but he does not give any records of their temperature. In 1747, 

 Le Monnier 7 found that he could remain for eight minutes in a bath 

 supplied by a thermal spring, the temperature of which was 44 to 45 ; 

 at the end of that time his skin was red and swollen, and his distress so 

 great that he was obliged to get out. No observations upon the 

 temperature of the body are given. Kurrer 8 and Neuhauss 9 have ob- 

 served that the temperature of stokers, working in a stoke-hole at 50 

 to 56, is raised to 37'6, or even to 381. 10 



Numerous experiments have been made to determine the effect of 



1 "Researches," London, 1839, vol. i. p. 20S. 



2 Phil. Trans., London, 1748, vol. xlv. p. 338. 



3 Ibid., 1758, vol. 1. pt. 2, p. 754. 



4 Ibid., 1775, vol. Ixv. pt. 1, pp. Ill and 484. 



5 Ibid., 1775, vol. Ixv. pt. 2, p. 463. 



6 Hist. Acad. roy. d. sc., Paris, 1764, p. 188. 



7 Ibid., 1747, p. 271. 



8 Deutsche Vrtljschr. f. off. Gsndhtspflg . , Braunschweig, (2), Bd. xxiv. S. 291. 



9 Virchow's Archiv, 1893, Bd. cxxxiv. S. 365. 



10 See also Crornbie, Indian Ann. Med. Sc., Calcutta, 1873, vol. xvi. p. 601. 



