CHAPTER I. 



NUTRITIVE FUNCTIONS — METABOLISM, OR WASTE AND 

 SUPPLY. 



Coextensive with life and lying at the very basis 

 of all life phenomena is a continuous change by waste 

 and supply of the material of which the body is com- 

 posed. This whole process of change is called metabo- 

 lism, or transformation. It is not only coextensive with 

 life, but it may be said to be life itself. It consists 

 necessarily of two parts — viz., an ascensive change, by 

 which new tissue is formed from crude material, and a 

 descensive change, by which old tissue is decomposed 

 and -eliminated from the body. The former is called 

 anabolism, the latter katabolism, or waste. This latter is 

 apparently the active, initiative agent of the whole pro- 

 cess. 



Waste. — The process of waste is so fundamental 

 that it must be thoroughly illustrated. 



i. Suppose, then, we had a pair of scales of enormous 

 size, and one of you (hearers or readers) were lying in a 

 comfortable position in one pan and a weight for perfect 

 counterpoise in the other. I shall suppose you at per- 

 fect rest physically and peace mentally, and, as contrib- 

 uting to this condition, perhaps smoking a cigar. The 

 equilibrium would not continue indefinitely ; if the scales 

 were delicate, not even for a minute. On the contrary, 

 even while we watch the experiment, your side of the 



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