ii THE THERMIC ECONOMY OF THE ORGANISM 73 



and in fourteen girls 37'191. Wunderlich found that there was 

 a rise of temperature of about 0'3 during menstruation ; Riehl 

 noticed that this hypertherniia is specially marked during the 

 pre-inenstrual period. 



Neither does Race cause any great difference in the average 

 temperature. Davy, however, considers that the temperature of 

 negroes, Indians, and Malays is some tenths of a degree higher 

 than that of Europeans. This difference appears, however, to 

 be the result of tropical climates rather than of race. Chrisholm 

 and Chalmers, indeed, assert that in hot countries the temperature 

 of Indians and English was the same. Furnell, a doctor attached 

 to the Madras hospital, confirmed this statement, while Living- 

 stone had noticed the same fact in the negroes of Africa. 



The more recent work of Glogner (1891) and of Eijkman 

 (1893) also go to show that no influence is exercised on tempera- 

 ture by race, and that of tropical climates is but slight. 



Forel took the temperature of his rectum at different seasons 

 of the year, and found that a rise in the temperature of the air 

 caused a slight rise in that of the rectum ; while Davy observed 

 that very intense cold caused the temperature of the arm -pit to 

 fall to 35:9. The same fact was noticed by Stapff. 



That great rises or falls in the external temperature can 

 modify the temperature of the body is shown by the fact that 

 death occurs from heat or cold. But what we have already said 

 proves that moderate differences in external temperature, although 

 they may cause variations of a few tenths of a degree in the 

 temperature of the body, are compatible with perfect health. In 

 other words, the temperature may be regulated at a somewhat 

 higher or lower level than the normal one, and the organism 

 still remain within physiological limits. 



The influence of Nourishment upon the temperature is 

 extremely slight. We have indeed seen that the daily curve is 

 not in the least affected by the hours of meals and that its 

 characteristic course remains unaltered during fasting. This 

 proves the course of the average temperature of the body to be 

 independent of the oscillations in the production of heat. When 

 combustion is more active after a meal (L. Fredericq and others), 

 and does not cause any sensible rise of temperature, it follows 

 that the loss of heat is proportionately increased, and compensates 

 for the increased production. 



We know that muscular activity exerts a preponderating 

 influence on the production of heat (Vol. III. Chap. I. 10). 

 Muscles form 40 per cent of the total weight of vertebrate 

 animals, and their active exercise is the best means of warming 

 the body in winter. 



Davy noticed that his temperature rose from 36'6 to 37*25 

 after various forms of muscular exercise, and fell to 36'1 after a 



