ANIMAL HEAT. 579 



and the temperature may rise so rapidly as to cause fatal symptoms within ten 

 or fifteen minutes. A hot moist air is far more oppressive and dangerous than 

 hot dry air. 



Baths exercise a potent influence on bodily temperature, hot baths increasing 

 and cold baths decreasing it. The effect of a cold bath is less if it follows a 

 hot bath. Thus Dill l found that his morning temperature varied from 33.7 

 to 36.6 C., after a hot bath (40-41 C.) it rose, in one instance, as high as 

 39.5 C., and after a cold bath it remained at 37 C. When, however, the 

 hot bath was omitted the cold bath reduced the temperature to 35.4 C. Bal- 

 jakowski 2 has recorded some very interesting results which show that the local 

 application of heat causes the bodily temperature to sink and the cutaneous 

 temperature of the part experimented upon to rise. The experiments were 

 conducted on young men, whose arms and legs were encased in hot sand at a 

 temperature of 55 C. When the arm was used the axillary temperature sunk 

 an average of 0.13 C. during the bath and subsequently 0.24 C., the corre- 

 sponding records of average rectal temperature being 0.23 and 0.31 C. In 

 case of the leg bath the corresponding records were axillary 0.06 and 0.32 

 C. ; and rectal 0.21 and 0.25 C. The cutaneous temperature of the limb 

 experimented upon increased materially, the average rise varying from 0.73 

 to 1.20 C., according to the part of the limb. Long-continued severe exter- 

 nal cold may prove fatal, but this is not necessarily due to the effect on bodily 

 temperature, for Milne- Ed wards 3 has shown that rabbits die within five or six 

 days when exposed to a temperature of 10 to -15 C., without the bodily 

 temperature falling more than 1 C. 



There is a general relationship between the frequency of the heart's beat and 

 the bodily temperature, especially in fever. Barensprung noted such a coinci- 

 dence between the diurnal variations of the pulse and bodily temperature ; and, 

 in fever, Aiken found that for each increase of 0.55 C. (1 F.) above the mean 

 normal temperature the pulse-rate was increased about ten beats per minute. 

 But the variations in the two do not always correspond either quantitively or 

 qualitatively. Liebermeister found in man that for a rise of each degree from 

 37 to 42 C. the increase in the pulse-rate was 12.6, 8.6, 8.7, 11.5, and 27.5 

 beats per minute respectively. Beljakowski's 4 experiments show that the 

 bodily temperature may fall and the pulse-rate rise in one set of experiments 

 the rectal temperature falling on an average 0.23 C. and the pulse increasing 

 on an average 6.85 beats per minute. After the local hot bath the temperature 

 remained subnormal, and the heart-beats became less frequent, and finally were 

 on an average from 2.7 to 3.1 beats per minute less than the normal rate. 



More important, however, than the pulse-rate is the effect of the amount 

 of blood supplied to any given part of the body. The mere lowering or rais- 

 ing of the arm is sufficient to alter the blood-supply to the part ; thus Romer 

 found that keeping the arm elevated for five minutes was sufficient to reduce 



1 British Medical Journal, 1890, vol. i. p. 1136. 



2 Vratch, 1889, p. 436; Provincial Medical Journal, 1890, p. 113. 



3 Comptes rendus de la Soc. de Biologic, 1891, vol. 112, pp. 201-205. 4 Loc. cit. 



