SYSTEMATIC ANALYSIS OF APPARATUS. Ill 



different kinds of nutrition : it must also be supplied 

 with material for warming and cooling itself. 



402. AT LEAST THREE DIFFERENT KINDS OF FOOD 



must be largely supplied: for nourishing the nervous 

 organs, for nourishing the muscular organs, and for fuel 

 (the calorific kind) while cooling, and smaller quantities 

 of other substances will be constantly or at times wanted. 



403. FOOD DIFFERS FROM AlR AND WATER IN THIS 



ALSO : that they are found in nature and need no prepa- 

 ration, while food is obtained by labor, needs much pre- 

 paration, and must be separated from useless or waste 

 substances incorporated with it. 



404. FOOD MAY BE ARRANGED in four classes : Nutri- 

 tion, which is of two very conspicuous varieties, the 

 nervous and muscular, and several less conspicuous vari- 

 eties; Calorific, which includes much, the larger part of 

 food; Cooling and Waste, that include unmasticated 

 seeds and indigestible harmful substances that should 

 never be eaten, and the fibrous woody parts of vegetables 

 and fruits, that are useful especially in spring and sum- 

 mer. 



f Nutritive. 



FOOD= J Calorific. 



I Cooling. 

 L Waste. 



405. (THE BODY HAS BEEN CONSTITUTED for activity, 

 and is kept in the best health when it is properly active. 

 As it was not anticipated that man would find his food 

 separated from waste, he has been constituted to sepa- 

 rate the useful from the useless substances in his diges- 

 tory organs ; hence it is best that he should do so.) 



406. ONE REASON THAT MAN REQUIRES DIGESTORY 

 ORGANS, and one use of them, is to dissolve out the use- 

 ful from the waste substance ; and as this binds the use- 

 ful with many fibres closely woven, in some cases the 

 process will be correspondingly tedious. 



402. What ? 403. How does ? 404. How ? Table. 405. How ? 

 406. What is - ? 



