TRANSFORMATION OF WORK. 



929 



substance, when burnt out of the body, is ascertained by experiment; 

 and, in the case of albuminoid bodies, the energy which would be de- 

 veloped from them, when oxidized, in the body, is calculated, by de- 

 ducting the energy remaining in a corresponding quantity of urea. 

 The following Table gives some of the results : 



According to this mode of estimating the value of food, as compared 

 with that which regards its composition only (p. 570), cheese still re- 

 tains a very high position, being inferior only to oils, fats, butter, and 

 cocoa nibs. It appears, moreover, that .55 parts of fat are equal to 

 1.15 of cheese, to 1.3 of pea meal, to 3.5 of lean beef, and to 5 parts 

 of potatoes. 



VALUE OF FOOD AS A SOURCE OF MOTOR POWER (Frankland}. 



Transformation of Mechanical into Calorific Work in the Body. 



Every kind of internal work, whether vital, mental, nervo-muscu- 

 lar, or mechanical, electric, or nutritive, excepting the solvent pro- 

 cesses, ultimately passes into heat within the body. The purely 

 external mechanical work is thought by some, however, to be an 



59 



