80 HUMAN PHYSIOLOGY. 



their appearance in the protoplasmic cells of the connective areolar tissue, 

 thus giving rise to the adipose tissue. Another portion probably undergoes 

 direct oxidation. 



The carbohydrate principles, after digestion, are absorbed as dextrose and 

 temporarily stored up in the liver as glycogen. The intermediate stages 

 which sugar passes through and the combination into which it enters between 

 its absorbtion and its elimination are but imperfectly understood. That it 

 contributes to the accumulation of fat is probable, though it is doubtful if it is 

 ever converted into fat. A large percentage of the sugar absorbed is at once 

 oxidized. The reduction of fat and sugar to carbon dioxid and water, under 

 which forms they are eliminated from the body, is accompanied by a dis- 

 engagement of a large quantity of heat. 



Water is present in all the fluids and solids of the body. It promotes the 

 absorbtion of new material from the alimentary canal; it holds the various 

 ingredients of the blood, lymph, and other fluids in solution; it hastens the 

 absorption of waste products from the tissues, and promotes their speedy 

 elimination from the body. 



Sodium chlorid is present in all parts of the body to the extend of no gm. 

 The average amount eliminated daily is 15 gm. Its necessity as an article of 

 diet is at once apparent. Taken as a condiment, it imparts sapidity to the 

 food, excites the flow of the digestive fluids, promotes the absorption and 

 assimilation of the albumins, influences the passage of nutritive material 

 through animal membranes, and furnishes the chlorin for the free hydro- 

 chloric acid of the gastric juice. In some unknown way it favorably promotes 

 the activity of the general nutritive process. 



The potassium salts are also essential to the normal activity of the nutri- 

 tive process. When deprived of these salts, animals become weak and ema- 

 ciated. When given in small doses, they increase the force of the heart-beat, 

 raise the arterial pressure, and thus increase the action of the circulation of the 

 blood. 



The calcium phosphate and carbonate are utilized in imparting solidity to the 

 tissues, more especially the bones and teeth. Many articles of food contain 

 these salts in quantities sufficient to restore the amount lost daily. 



The vegetable acids increase the secretions of the alimentary canal, and are 

 apt, in large amounts, to produce flatulence and diarrhea. After entering 

 into combination with bases to form salts, they stimulate the action of the 

 kidneys and promote a greater elimination of all the urinary constituents. 

 In come unknown way they influence nutrition; when deprived of these acids, 

 the individual becomes scorbutic. 



The accessory foods, coffee and tea, when taken in moderation, overcome 

 the sense of-fatigue and mental unrest consequent on excessive physical and 



