ANIMAL HEAT. 31 1 



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 0.). This maybe 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 small 

 amount of 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 caout- 

 chouc alternately stretched and recoiling becomes hot. 



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

 same in temperate and tropical climates (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. 



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 alco- 

 holic 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 0.) ; 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, 

 according to the tables of Tiedemann and Rudolphi, averages 101 (38.3 

 C.). The extremes recorded by them were 96 and 106, the former in 

 the narwhal, the latter in a bat (Vespertilio pipistrella). In Birds, the 

 average is as high as 107 (41.2 C.) ; the highest temperature, 111.25 

 (46.2 C.) ; being in the small species, the linnets, etc. Among Eep- 

 tiles, while the medium they were in was 75 (23.9 C.), their average 

 temperature was 82.5 (31.2 0.). As a general rule, their temperature, 

 though it falls with that of the surrounding medium, is, in temperate 

 media, two or more degrees higher; and though it rises also with that 

 of the medium, yet at very high degrees it ceases to do so, and remains 

 even lower than that of the medium. Fish and invertebrata present, as 

 a general rule, the same temperature as the medium in which they live, 

 whether that be high or low; only among fish, the tunny tribe, with 

 strong hearts and red meat-like muscles, and more blood than the average 

 fish have, are generally 7 (3.8 C.) warmer than the water around them. 



