VARIATIONS OF THE MEAN TEMPERATURE. 437 



Like all other substances, the human body is enlarged by heat. A man 

 weighing 60 kilos., and whose temperature is raised from 37C. to 40C., is 

 enlarged about 62 cubic centimetres. Connective-tissue (teudoii) is extended by 

 heat, while elastic tissue, the skin, like caoutchouc, are contracted (Lombard and 

 Walton). 



213. Variations of the Mean Temperature. 



(1.) General Climatic and Somatic Influences. In the tropics, the 

 mean temperature of the body is about lC. higher than in temperate 

 climates, where again it is several tenths of a degree warmer than in 

 cold climates (J. Davy) ; but this has recently been denied by Boileau 

 and Pinkerton. This difference is comparatively trivial, when we 

 remember that a man is subjected to a variation of over 40C. in passing 

 from the equator to the poles. Observations on more than 4000 persons 

 show that when a person goes from a warm to a cold climate, his tempera- 

 ture is but slightly diminished, but when he goes from a cold to a 

 warm climate his temperature rises relatively considerably more. In the 

 temperate zone, the temperature of the body during a cold winter is usually 

 0'1-0'3C. lower than it is on a warm summer day. The elevation of a 

 place above sea-level has no obvious effect on the temperature of the 

 body. There seems to be no difference in different races, nor in the 

 sexes, other conditions being the same. Persons of powerful physique 

 and constitution are said to have generally a slightly higher temperature, 

 than feeble, weak, anaemic persons. 



(2.) Influence of the General Metabolism. As the formation of 

 heat depends upon the transformation of chemical compounds, whose 

 chief final products, in addition to H 0, are C0 2 and urea, the amount 

 of heat formed must go pari pasu with the amount of these excreta. 

 The more rapid metabolism which sets in after a full meal causes a rise 

 of temperature to several tenths of a degree (" Digestion-fever"). As 

 the metabolism is much diminished during hunger, this explains why 

 the mean temperature in a fasting man is 36*6, while it is 37'17 on 

 ordinary days (Lichtenfels and Frohlich). 



Jiirgenseu also found that the temperature fell on the first day of inanition, 

 (although there was a temporary rise on the second day). In experiments made 

 upon starving animals, the temperature at first fell rapidly, then remained con- 

 stant for a considerable time, while during the last days it fell considerably. 

 Schmidt starved a cat on the 15th day the temperature was 3S'6; on the 16th, 

 38-3; 17th, 37'64; 18th, 35'S ; 19th (death) = 33 '0. Chossat found that starving 

 mammals and birds had a temperature 16C. below normal on the day of their 

 death. 



(3.) Influence of Age. Age has a decided effect upon the tempera- 

 ture of the body. The extent of the general metabolism is in part an 



