702 PHYSIOLOGY 



each of the firs* two should be not less than 70 grm. a day. The protein 

 should have a mixed origin and should include a certain amount of animal 

 protein. 



(3) It should include a certain proportion of fresh foods, such as green 

 vegetables, meat and eggs, and in the case of children, milk, in order to 

 supply the necessary accessory food substances. 



(4) It must contain a proper proportion of the salts, especially sodium, 

 calcium, potassium, chlorides and phosphates. 



(5) It must be palatable. Appetite is an essential factor for the secre- 

 tion of the digestive juices and therefore for the digestion and assimilation 

 of the food, so that good cooking becomes an important condition for the 

 maintenance of health. The use of various flavouring agents and condiments, 

 which is general throughout all races, is therefore physiologically justified. 



ALCOHOL. When alcohol is taken by man in moderate quantities, the 

 greater part of it undergoes oxidation and leaves the body as carbon dioxide 

 and water. About 10 per cent, which escapes oxidation is excreted unaltered 

 by the lungs and urine. This oxidation of alcohol is a result of true utilisa- 

 tion, since the addition of a certain amount of alcohol to the food does not 

 result in an increase of the output of carbon dioxide. In small quantities 

 therefore alcohol can act as a food. This function however is quite un- 

 important, and is overshadowed by the poisonous action of this substance. 

 A man unaccustomed to its action cannot take more than 16 to 25 grm. 

 without experiencing its poisonous effects. This amount of alcohol represents 

 a total heat value only of 112 to 175 Calories, i. e. only about 5 per cent, 

 of the total energy requirements of the body. Very rarely therefore 

 can we be justified in administering alcohol as a food. Its value in a diet 

 is entirely that of an accessory or adjuvant in exciting appetite by its 

 taste and smell, an advantage largely counterbalanced by the danger 

 of introducing a poison into the body which on long continuance tends to 

 set up various degenerative changes in the tissues; and if taken in any 

 quantity at one time, it causes a temporary abolition of those processes of 

 inhibition and control which have been the determining factors in the 

 survival of the race throughout the struggle for existence. 



