CHAPTEK XII. 



NUTRITION. 



Nature of the forces involved in nutrition Protoplasm Definition of vital 

 properties Life, as represented in development and nutrition Principles 

 which pass through the organism Principles consumed in the organism 

 Nitrogenized principles Development of power and endurance by exercise 

 (Training) Non-nitrogenized principles Formation and deposition of fat 

 Conditions under which fat exists in the organism Physiological anatomy 

 of adipose tissue Conditions which influence nutrition Products of dis- 

 assimilation. 



NUTRITION proper, in the light in which we propose to 

 consider it in this chapter, is the process by which the phys- 

 iological decay of the tissues and fluids of the body is com- 

 pensated by the appropriation of new matter. All of the 

 physiological processes that we have thus far studied, in- 

 cluding circulation, respiration, alimentation, digestion, ab- 

 sorption, and secretion, are to be viewed in the light of 

 means directed to a single end ; and the great function, to 

 which all the others are subservient, is the general process 

 of nutrition. 



The nature of the main forces involved in nutrition, be 

 it in a highly-organized part, like the brain or muscles, or a 

 tissue called extra-vascular, like the cartilages or nails, is 

 unknown. The phenomena attending the general process, 

 however, have been studied most carefully, and certain im- 

 portant positive results have been attained ; but we find no 

 more satisfactory explanation of the nature of the causative 

 force of nutrition in the doctrines of to-day than in the 

 speculative theories of Pythagoras. 



