472 PHYSIOLOGICAL CHEMISTRY. 



bustion of the food the heat of combustion of the urine and faeces, 

 which corresponded to the food taken plus the quantity of heat 

 necessary for the swelling up of the albuminous bodies and the 

 solution of the urea. RUBBER has also tried to determine the heat 

 of combustion of the proteids (inuscle-proteids) decomposed in the 

 body of rabbits in starvation. According to these investigations, 

 the physiological heat of combustion in calories for each gramme of 

 substance is as follows : 



TABLE XYI. 



1 grm. of the Dry Substance. Calories. 



Proteids from meat 4424 



Muscle 4000 



Proteids in starvation B842 



Fat (average for various fats) 9300 



Carbohydrates (calculated average) 4100 



The physiological combustion value of the various foods belong- 

 ing to the same group is not quite the same. It is, for instance, 

 3969 calories for a vegetable albuminous body, conglutin, and 4424 

 calories for an animal albuminous body, syntonin. According to 

 BUSIER, we may consider the normal heat value per 1 grm. of ani- 

 mal proteid as 4233 calories, and of vegetable proteid as 3960 calo- 

 ries. When a person on mixed diet takes about 60$ of the proteids 

 from animal foods and about 40$ from vegetable foods, then we 

 may consider as the value of 1 grm. of the proteid of the food as 

 about 4100 calories. The physiological value for each of the three 

 chief groups of organic foods, by their decomposition in the body, 

 is in round numbers as follows : 



TABLE XVII. 



Calories. 



1 grm. proteid = 4100 



1 " fat =9300 



1 " carbohydrate = 4100 



As above stated several times, the fats and carbohydrates may 

 decrease the metabolism of proteids in the body, while, on the other 

 hand, the quantity of proteids in the body or in the food acts on 

 the metabolism of fat in the body. In the physiological combustion 

 the various foods may replace one another to a certain extent, and 

 it is therefore important to know in what proportion they replace 

 one another. The investigations made by RUBHER have taught us 



