444 HANDBOOK OF PHYSIOLOGY. 



The salts, over L0 grms., would be supplied by the meat 16 grnus., 

 the bread 12 grms., and vegetables about 4 grms. The fluids should 

 consist of about 2,500-2,800 grms., and might be given as water, with 

 or without tea, coffee, or cocoa (which are chiefly stimulants), together 

 with a small proportion of alcohol. 



Variations in Diet Tables. 



For infancy. Milk affords a natural and perfect diet for infants. 

 The amount which an infant during the first month should take is not 

 less than 1 kilogramme (2Jlbs.) per diem. In 1,000 grms. there would 

 be about 6.6 grms. nitrogen and 80 to 90 of carbon. This allows for a 

 gain of weight of 2 to 5 oz. in the time. 



For climate. Very slight alteration is necessary. For warm climates, 

 slightly increase the carbohydrates. 



For hard labor. All the articles of diet should be increased to make 

 up for the increased metabolism. 



Fattening diet. In such a diet an excess of carbohydrates should be 

 present. 



To reduce obesity. The fats and carbohydrates should be diminished, 

 but the proteids should be relatively increased. 



To increase muscle. It has been found that a diet consisting largely 

 of proteids in considerable amount combined with such passive exercise 

 as that obtained by massage, will cause the body to put on flesh. 



For training. The whole diet should be increased, possibly preceded 

 by a diet in which the proteid is in excess. 



For brain work. The chief essential is that the diet should consist of 

 easily digestible materials. 



Income and Output of Energy. 



The food must be considered from another point of view in addition 

 to that from which we have been considering it. It not only makes 

 up for the substances eliminated from the body, but it also supplies 

 potential energy to balance the energy set free in the living body as 

 heat and movement. The amount of heat is measured in terms of 

 calories, as has been already pointed out. The work done may be ex- 

 pressed in terms of foot-pounds (English system), or metre-grammes, 

 or metre-kilogrammes (metric system). The calories may also be ex- 

 pressed in terms of work, as heat is also, as has been said, a mode of mo- 

 tion. The heat-unit Ca, may be transformed into metric work-unit by 

 multiplying by 42 and dividing by 1000, and the converse. 



