310 HAND-BOOK OF PHYSIOLOGY. 



between 50 and 53-5 F. (10-12 C.); whereas while lying close to the 

 body of the mother, their temperature is only 2 or 3 degrees F. lower 

 than hers. The same law applies to the young of birds. 



Sex. The average temperature of the female would appear to be very 

 slightly higher than that of the male. 



Period of the Day. The temperature undergoes a gradual alteration, 

 to the extent of about 1 to 1*5 F. (*54 '8 C.) in the course of the day 

 and night; the minimum being at night or in the early morning, the 

 maximum late in the afternoon. 



Exercise. Active exercise raises the temperature of the body from 1 

 to 2 F. (-54 1.08 C.). This may be partly ascribed to generally in- 

 creased combustion-processes, and partly to the fact, that every muscular 

 contraction is attended by the development of one or two degrees of heat 

 in the acting muscle; and that the heat is increased according to the 

 number and rapidity of these contractions, and is quickly diffused by the 

 blood circulating from the heated muscles. Possibly, also, some heat 

 may be generated in the various movements, stretchings, and recoilings 

 of the other tissues, as the arteries, whose elastic walls, alternately dilated 

 and contracted, may give out some heat, just as caoutchouc alternately 

 stretched and recoiling becomes hot. But the heat thus developed cannot 

 be great. The great apparent increase of heat during exercise depends, 

 in a great measure, on the increased circulation and quantity of blood, 

 and, therefore, greater heat, in parts of the body (as the skin, and espe- 

 cially the skin of the extremities), which, at the same time that they feel 

 more acutely than others any changes of temperature, are, under ordi- 

 nary conditions, by some degrees colder than organs more centrally 

 situated. 



Climate and Season. The temperature of the human body is the same 

 in temperate and tropical climates. (Johnson, Boileau, Furnell.) In 

 summer the temperature of the body is a little higher than in winter; the 

 difference amounting to about a third of a degree F. (Wunderlich.) 



Food and Drink. The effect of a meal upon the temperature of a body 

 is but small. A very slight rise usually occurs. Cold alcoholic drinks 

 depress the temperature somewhat (-5 to 1 F.). Warm alcoholic 

 drinks, as well as warm tea and coffee, raise the temperature (about -5 F.). 



In disease the temperature of the body deviates from the normal stand- 

 ard to a greater extent than would be anticipated from the slight effect 

 of external conditions during health. Thus, in some diseases, as pneu- 

 monia and typhus, it occasionally rises as high as 106 or 107 F. (41 

 41 '6 C.); and considerably higher temperatures have been noted. In 

 Asiatic cholera, on the other hand, a thermometer placed in the mouth 

 may sometimes rise only to 77 or 79 F. (25 26-2 C.). 



The temperature maintained by Mammalia in an active state of life, 



