ANIMAL HEAT. 173 



short period, they have equal temperatures; neither is 

 warmer or colder than the other. 



404. If a piece of wood or of dead flesh be put into hot, or 

 even boiling water, it soon is as warm as the fluid. If it be 

 put into cold water or snow, it soon becomes as cold as that. 

 If ice be put into hot water, it receives a part of the heat of 

 the fluid. It first melts, and its water is then warmed up to 

 the temperature of the original water ; while this, losing its 

 heat, is cooled down to the temperature of the water from 

 the ice, and, finally, both have the same degree of heat. 

 The same effect is seen when any substances are placed in 

 air of different temperature. When the atmosphere is at 32, 

 water freezes, and solids become as cold as ice. On the 

 other hand, water boiled, and the eggs and the beef were 

 heated up to the temperature of the room \fhich Sir Charles 

 Blagden entered. 



405. But it is not so with living beings. Their tempera- 

 ture does not follow that of the surrounding and contiguous 

 objects. The temperature of the warm-blooded animals, 

 of man, horses, and birds, for instance, scarcely varies 

 with any extremes of cold or heat to which they may be ex- 

 posed. The usual temperature of man is 98. If a ther- 

 mometer be placed in his mouth, in the East Indies or in 

 the arctic regions, it will be found the same. The body 

 sustains its own temperature in the cold medium, and is no 

 warmer in the heated room. 



406. If this were not so, if the temperature of our bodies 

 should follow that of the surrounding medium, the most fatal 

 consequences would ensue. The blood and the flesh would 

 be frozen, and all our motions stayed, and life extinguished, 

 in the severe weather of winter, even in the temperate cli- 

 mates; and, on the other hand, the fatty portions of our 

 frame would sometimes, in the tropical climates, melt, and 

 the blood would boil in such experiments as Blagden tried. 



15* 



