270 RELATION OF FOOD TO NUTRIMENT. 



now the change has been wrought it is not easy to determine. Should 

 any portion of the food, however, pass from the stomach undis- 

 solved, it is subjected to a supplementary digestive process in the 

 bowel. The intestinal fluid and the pancreatic juice act as solvents; 

 and the bile (though it does not appear to possess any solvent 

 power) is incorporated with the food, which is now in a condition 

 ready for absorption and for application to its proper use. Under 

 meat-diet there is a more copious secretion of gastric juice; under 

 vegetable the saliva is more abundant; showing that there is pro- 

 vision in the system for variation in the food, and that uniformity 

 in food is immaterial. 



The primary use of nitrogenous food is to develop and renew 

 the various tissues ; its secondary use is to facilitate the absorption 

 of non-nitrogenous food. Wherever there is life, nitrogenous 

 food must be present to sustain it; non-nitrogenous food con- 

 tributes to its support ; without the former the latter would be use- 

 less ; the former being present, the latter is a very valuable auxiliary. 

 Nitrogenous food is the main tissue-former, but it also to some 

 extent produces force. Non-nitrogenous food produces force, but 

 it also in some measure contributes to the formation of tissue. 

 Indeed, the best materials for the production of working power as 

 well as heat, are the non -nitrogenous principles; and of these the 

 fats are more effective than others. 



Non-nitrogenous Food Non-nitrogenous food comprises 

 fats, starch and sugar, alcohol and vegetable acids. 



Fat is found in both animal and vegetable products. It under- 

 goes little change in the mouth and stomach; but, by the action of 

 the pancreatic juice in the small intestine, it is digested and re- 

 duced to a minute state of subdivision, ready for absorption through 

 small projecting filaments into the lacteal system, by which it is 

 conveyed into me general circulation of the blood. It is by this 

 means deposited in the various tissues, fills up interstices between 

 muscles, bones and vessels, gives regularity to the form of the body, 

 assists in the retention of the heat of the body and forms a reserve 

 of force-producing material, to be utilized when required. It holds 

 the highest place as a heat-former, for by its oxydation heat is gen- 

 erated in the system. It also appears to facilitate the assimilation 

 of other forms of food, and there is a prevalent opinion that, if it 

 is not supplied in sufficient quantity, scrofulous disorders are de- 

 veloped. 



Starch cannot be assimilated without change; when raw, it 

 passes out of the system unaltered. If it is boiled, the granules 

 burst and the particles are ready for conversion into sugar. This 

 conversion would take place in the mouth, under the influence of 

 saliva, if the food remained there for a sufficient length of time. 

 But it is usually swallowed at once, and when it reaches the stomach 

 the gastric juice arrests the action of the saliva. It then passes on 

 in a semi-fluid state to the emaU intestine where the digestion 



