HEAT AND LIFE. 4 o 9 



animal heat ; that is to say, it directs and in a manner oversees its 

 production and diffusion according to the varying needs of the system. 

 Every lesion or affection of this system reacts on the physiological 

 processes, and particularly on the evolution of heat. By cutting the 

 fdament of the great sympathetic nerve on only one side of a rabbit's 

 neck, Claude Bernard produced an elevation of temperature of several 

 degrees on that side. The blood flows toward the point where the 

 action of the nervous system is suspended under any influence what- 

 ever, bringing with it an increase of heating force. At a point where 

 the reverse occurs, the vessels contract, and the temperature falls. 



Imperfect nutrition and fasting act on the animal heat, but not 

 directly. The organism keeps up to its normal degree of temperature 

 till it lias exhausted its reserved store of combustible substances. 

 Then it cools slowly down to a much lower degree. Thus, a rabbit, 

 starved by Chassat, showed the first day a warmth of 38 4' (cent.) ; 

 two days before its death, 38 1' ; the evening before, 37 5' ; and at the 

 moment of death, 27. By placing it in a warm medium the moment 

 it was about to die, the apparent activity of its functions was restored 

 for a little while ; but the renewal is of brief duration : the anatomical 

 elements have absolutely lost their spring. 



The hand of an invalid, suffering from inflammation of the chest, or 

 from an attack of fever, is burning ; that of one affected by serious 

 asthma, or by emphysema, is as cold to the touch as marble. This is 

 because animal heat varies greatly in different pathological states. 

 Sometimes it rises, sometimes it falls; and the morbid influence is 

 scarcely ever compatible with the body's degree of normal tempera- 

 ture. In Hippocrates's time, when examination of the pulse was not 

 yet practised, the increase of temperature was the only element in the 

 commonest of maladies, fever. Galen defines it quite simply as an 

 extraordinary heat (calor praeternaturalis substantia febrium). The 

 ancients did not err. It has been admitted and proved in our days, 

 that the elevation of the animal heat is just the specific character of 

 the febrile condition. On the one hand, there is never any fever when 

 the temperature continues at the normal degree ; on the other, the 

 rapidity of the pulse may reach the utmost limits, without any febrile 

 movement, as is seen in hysteria. Whenever the bodily heat exceeds 

 38 (cent.), it may be affirmed that there is fever; and, whenever it falls 

 below 36, there is what is termed algidity. So that the normal heat 

 varies within the narrow range of scarcely two degrees. Beyond these 

 limits, that is, above 38 and below 36, the temperature points out 

 some morbid trouble. In common intermittent fever, it rises two or 

 three hours before the chill, reaches a maximum at the close of it, and 

 then falls. Acute and decided inflammations, such as pneumonia, 

 pleurisy, bronchitis, erysipelas, etc., are marked by a period of thirty- 

 six hours, or about two days, during which the heat rises slowly to 41 # 

 Toward the third day, this heat decreases, ready to reappear in exacer- 



