CONTROL OF BODY TEMPERATURE AND FEVER 715 



temperature is carefully taken by leaving the bulb of the thermon* 

 under the tongue for a minute or more, it is practically the Bame as the 

 temperature of the arterial blood of the hand when this Lb exposed to the 

 ordinary conditions of outside temperature. Greater differences than 

 1° c. i,, the temperature of differenl regions of the body are often ob 

 served in feeble individuals and in those with some circulatorj disturb- 

 ance. 



FACTORS IN MAINTAINING THE BODY TEMPERATURE 



The body temperature represents the balance between heal production 

 and heal loss. The production is effected mainly in the muscles by the 

 oxidative processes which are constantly ensuing there. When the 

 activity of the muscles is abolished by paralyzing the terminations 

 tin- motor nerves with curare, the temperature <>t" warm-blooded animals 

 immediately falls or rises a rding to the temperature "t' the environ- 

 ment. A curarized warm-blooded animal is thus made to behave lil 

 cold-blooded one. Increased muscular activity, on the other hand, 

 promptly raises the body temperature by 1" <>r 2 : (•'.. above which, how- 

 ever, a further rise does not occur, provided nothing has been done to 

 interfere with the mechanism by whieh the excess of heat is L r <»t rid 

 from the body. The temperature in such cases adjusts itself at n higher 



level, ;it which it remains fairly constant however strenuous th< 



cise. It is possible that a certain amount of heat may also he generated 

 by the chemical processes occurring in the liver and other viscera, hut 

 when compared with the muscles this source of heat is undoubtedly in- 

 significant. Many of these chemical pr isses, as in the liver, instead 



of producing actually absorb heat, so that the balance between 1 

 producing and heat-evolving mechanisms may or may not come out in 

 favor of the liberal ion of heat. 



The production id' heat goes on all the time in muscles mi account 

 the condition of tonic contraction in which they are held see page S H . 

 and which is also necessary for keeping the joints in the proper deg 

 of flexion or extension. When more heat is required by the animal body, 

 the tone of the muscles increases independently of the function which 

 they may he performing in controlling the position of the joints. -This 

 increased tone may become bo pronounced that it causes visible conti 

 tions, which we recognize as shivering. Whenever the irfsensible hyp 

 tonicity and the shivering are inadequate to produce a sufficient amount 



of heat, the animal inst inct i\ el\ moves about in order that tl iter 



contractions may liberate more heat. 



The heat is produced in the muscles hy oxidation of tin- foodstuffs that 



have been assimilated from the blood. Even during the p 



