420 ANIMAL HEAT. [CHAP. XXX. 



The best experiments on the temperature of internal parts, are 

 those of MM. Becquerel and Breschet, who employed a thermo- 

 electric apparatus, consisting of two wires of different metals, 

 soldered together, and having their free ends brought into commu- 

 nication with an excellent thermo-electric multiplier, with an index 

 to show lOths of a degree. The wire, passed through various parts 

 of the body, indicated the temperature of the tissues in contact with 

 the point of contact of the two metals. Passing this 1^ inch into 

 the calf of the leg, the temperature was found to be 98 F., while at 

 a depth of ^ inch it was only 94, showing the cooling from the 

 surface inwards. The superficial fascia over the biceps was nearly 

 3 lower than the muscle itself ; on compressing the brachial artery, 

 so as to intercept the flow of blood, the temperature immediately 

 fell several lOths of a degree. So after the ligature of the main 

 artery for aneurism, the temperature is well known to fall, and to 

 require to be economised with increased clothing. Professor Fiik 

 obtained the following results in twelve experiments upon living 

 dogs. No difference in the temperature was observed between the 

 right and left ventricle of the heart. The highest degree of warmth 

 was always met with in the vagina and rectum (101'75 to 105-79). 



As exercise is attended with quickened circulation, more active 

 respiration, a more abundant interchange of oxygen and carbonic 

 acid, so it occasions an augmentation of animal temperature. The 

 secretions are more copious there is a more energetic nutrition 

 the quantity of food required is greater, and we all know how much 

 more keen our appetites are, and how much more food we consume 

 when engaged in employments requiring active exercise, than in 

 sedentary occupations. MM. Becquerel and Breschet have ob- 

 served, 'that the muscles during their contraction become hotter by 

 2 or 3, a fact which one of us can attest from an experiment on 

 the biceps in his own person, made by these gentlemen themselves. 



Sleep, as it is attended with diminished frequency of respiration 

 and pulse, and a smaller evolution of carbonic acid, is also marked 

 by a slight fall of temperature, viz., of from 1 to 3 F. 



Age has been shown by Dr. Edwards to have much influence on 

 temperature. Old persons, and very young ones, are alike unable to 

 preserve their proper warmth without external aid, and have not the 

 same power as adults of generating heat. For example, he found that 

 young carnivorous and rodent animals, when placed in an atmosphere 

 of 50 F. apart from the body of the mother quickly became cold, 

 though when lying near her they continued within 2 or 3 of her 

 temperature. So, young sparrows one week old were at 97 F. in 



