chap, xxxix.] REGULATION OF ANIMAL HEAT. 483 



furnished with a lid, stuffing being between the latter 

 and the calorimeter top. Loss of heat is thus pre- 

 vented. Through the outer case and calorimeter a 

 tube 1 passes to convey air to the animal. The tube 

 2 for conducting away the foul air is bent several 

 times through the water of the calorimeter, so that 

 the air parts with all the heat it has gained before 

 escaping from the apparatus. A thermometer dips 

 into the water. The temperature of the water in 

 the calorimeter is taken, next the temperature of 

 the animal is ascertained by means of a thermometer 

 in the rectum. The animal is then placed in its box, 

 which is quickly made air-tight, its tubes for the 

 entrance and exit of air being attached, and is 

 without delay lowered into the calorimeter, the whole 

 being closed, and left for some time. At the end of a 

 definite time the water in the calorimeter is mixed 

 by means of an agitator, whose handle projects 

 through the lid of the box, and the temperature of the 

 water read off. The animal is then removed and its 

 temperature tested. The weight of water in the 

 calorimeter, multiplied by its gain in degrees -of tem- 

 perature, added to the sum of the weight of the 

 metal case x its' specific heat x its gain in tempera- 

 ture, gives the units of heat gained by the calori- 

 meter. If the animal has gained or lost in heat, the 

 difference in heat units gained or lost is obtained by 

 multiplying the weight of the animal into its specific 

 heat (083) into the difference of temperature, and 

 this must be added to or subtracted from the calori- 

 meter total, as the case may be. 



According to Helmholtz, the quantity of heat 

 produced daily by man is about 2,700 calories. 



Regulation of animal heat. The tempera- 

 ture of the animal body is regulated largely by the 

 loss of heat. Heat is lost to a large extent in warm- 

 ing the ingest-a, to a much larger extent, however by 



