TOTAL AND SPECIFIC HEAT l/ 



grammeter are used sometimes, and represent 1,000 times 

 the calorie and grammeter respectively. 



Total and Specific Heat. The temperature of a body in- 

 dicates nothing as to the quantity of the heat it contains. 

 The degree of heat requires only a thermometer to deter- 

 mine it, but the quantity depends on the temperature, the 

 weight and the specific heat of the substance in question. 



Specific heat is analogous to specific gravity. Water is 

 taken as the standard in both cases. If it require only .5 ca- 

 lorie to raise I gram of a certain substance I degree C., the 

 specific heat of that substance is said to be .5. The specific 

 heat of the body is .8 ; that is, whereas it requires a certain 

 amount of heat to raise 150 pounds of water to a certain 

 temperature, it would require only .8 as much to raise a hu- 

 man body weighing the same to the same temperature. To 

 find the total heat in calories in any body it is only necessary 

 to multiply the weight (in grams) by the specific heat and 

 by the temperature C. Estimates made by calorimetry from 

 these data and from the potential value of the different foods 

 give the total daily heat production as about 2,500,000 ca- 

 lories for the average individual. This is equal to about i,- 

 400 calories per hour per kilo weight. 



The English heat unit is the pound-degree F. It is the 

 amount of heat necessary to raise I pound of water i degree 

 F. Its mechanical equivalent is the force necessary to raise 

 i pound 772 feet. The estimates just given in the metric 

 system when translated to English nomenclature give the to- 

 tal heat production for 24 hours as about 8,400 pound- 

 degrees, or 2.5 per hour per pound weight. These figures are 

 given as only approximate and are subject to change by many 

 causes, such as sex, cardiac and respiratory activity, internal 

 and external temperature, exercise, digestion, age, nervous 

 influences, the body weight, etc. 



Thermogenesis. Thermogenesis, or the production of 

 heat, is the result of activity on the part of the tissues, nerves 

 and centers. Now, the potential energy of the food stuffs is 



