HEAT AND LIFE. 4l3 



which, carrying the blood continually from the surface to the centre, 

 bears heat also along with it, then at a given moment it falls into con- 

 vulsions, the beating of its heart ceases, and it dies uttering a cry. 

 By means of the thermometer it is noted that the temperature of the 

 animal, in every case, is higher by four or five degrees (cent.) than the 

 figure which represents the normal warmth. Thus at first the animal 

 is excited, its functions seem to be performed with fresh vigor, very 

 much as, in the first rays of April sunshine, the pulsations of life in all 

 beings become more rapid ; but this stimulus is only fleeting, and soon, 

 when it reaches a certain degree, this heat gives place to the cold of 

 death. Bernard carefully examined animals dying under these con- 

 ditions, and the first phenomenon that struck him was the rapidity 

 with which corpse-like rigidity came on. The heart grew suddenly 

 insensible to any stimulus ; effused spots appeared at several points 

 on the skin. The heat fixed in coagulation the soft matter that com- 

 poses the muscular fibres. These had the look of being struck with 

 lightning. On the other hand, the arterial blood of the animal 

 grew black, ill-supplied with oxygen, overloaded with carbonic acid, 

 and assumed the look of venous blood. Yet in this state the blood 

 has not lost its physiological properties, and under the influence 

 of a new supply of oxygen can regain its normal state, and grow 

 ruddy again. The heat, provided the degree be not too elevated, only 

 promotes activity in sanguine combustion, without changing the blood. 

 Nor does the nervous system either appear to suffer much. The ele- 

 ment most deeply affected is muscle; heat is a poison of the muscular 

 system, like sulpho-cyanuret of potassium, and the upas-antiar. It is 

 the loss of the vital properties of this system, which, by bringing about 

 rigidity of the muscles, then the stoppage of circulation, and conse- 

 quently of respiration, is a necessary cause of death. This destruc- 

 tion of the contractile muscular fibre occurs toward 37 or 39 in 

 cold-blooded animals, toward 43 or 44 in mammals, toward 46 or 

 48 in birds, that is, speaking generally, at a temperature five or six de- 

 grees higher than the natural temperature of the animal. Bernard 

 calls attention to the fact that in no case is it allowable to suppose 

 that life opposes a kind of resistance to the excessive heating ; on the 

 contrary, vital movement tends to quicken it, and that may be readily 

 understood. The internal heat produced by the animal unites with 

 the acquired heat, and the renewal of the blood, which is the condi- 

 tion of the heating, then occurs with much greater activity. Let us 

 add that quite lately Demarquay applied this toxic action of heat on 

 the muscles in the happiest manner, and without suspecting it. He 

 cured patients suffering from those frightful muscular contractions 

 which characterize tetanus, by subjecting them to the influence of ca- 

 loric, and making them take very hot air-baths. The rise of tempera- 

 ture in the tetanized muscles was sufficient to modify them, and restore 

 them to a healthy state. Here the poison worked a cure. 



