470 AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



stances which have little or absolutely no influence upon the temperature of 

 the adult. 



The mean temperature of the female is said to be slightly lower than that 

 of the male In observations on children Sommer noted a difference of 0.05° 

 ('.. and Fehlinga difference of 0.33° C. 



Individuals with vigorous constitutions have a somewhat higher temper- 

 ature than those who are weak. 



Records obtained by various European investigators indicate that the bodily 

 temperature is subjected to regular diurnal variations. The limits of variation 

 in health are from 1° to 2° C. The maximum temperature observed is usu- 

 ally from 5 to 8 p. If. (mean, about 7 p. m.) ; the minimum, from 2 to 6 a. m. 

 (mean, about 4 a. M.J. Carter's 1 experiments on rabbits, cats, and dogs show 

 that rhythmical temperature-changes occur in these animals which agree with 

 those noted by Jurgensen in man. This same rhythm is stated to occur during 

 fasting, so that the ingestion and the digestion of food cannot he claimed to 

 account for it; moreover, it is present in fever and not disturbed by muscular 

 activity and by cold baths. If an individual works at night and sleeps during 

 the day, thus reversing the prevailing custom, the temperature curve is more 

 or less modified, but, according to Mosso, 2 not reversed as stated by Krieger. 3 

 Chclmonski found, however, in old persons that the temperature variations 

 are not uncommonly inverted, being higher in the morning and lower in the 

 evening. 



Insufficient diet causes a lowering of the temperature; a liberal diet tends 

 to cause a rise slightly above the normal mean, especially during forced feeding 

 or when the food is particularly rich in fats and carbohydrates. There is a 

 rise during digestion which is usually slight, but it may reach 0.2° or 0.3°, the 

 increase being due chiefly to the activity of the intestinal muscles (see p. 431). 

 Although considerably more heat is produced during the periods of digestion 

 than during the intervals, the excess is dissipated almost as rapidly as it is 

 formed, so that but little heat is permitted to accumulate and thus cause a rise 

 of temperature. Hot drinks and solids tend to augment, and cold drinks and 

 solids to lower bodily temperature. In the nursing child I temme found that the 

 n.tal temperature sinks during the first half-hour after taking food, then rises 

 during the next Bixty to ninety minutes to a point from 0.2° to 0.8° C. higher 

 than the temperature before feeding, and falls again during the next thirty to 

 sixty minute-. 



All condition- which increase metabolic activity are favorable to an increase 

 of temperature. Thus, during the activity of the brain, glands, muscles, etc., 

 more heat is produced than when the tissues are at rest; indeed, so abundant 

 is heat-production during severe muscular exercise that the temperature of the 

 body may rise a- much as <>..~,° to 1.5° C. (l°to 2.7° F.). During sleep the 

 temperature falls from <)..'5° to 0.9° C. or more in young children. 



: Journal of Nervous and Mental Diseases, 1890, vol. xvii. p. 782. 

 - Archives it<ili>„ m < ,U biologic, L887, t. viii. p. 177. 

 3 Zeilsckriftfilr Biologic, 1869, Bd. \. S. 479. 



