NUTRITIONAL PHYSIOLOGY 



CHAPTER I 

 INTRODUCTION 



The Modern Emphasis in Biology. Living things are 

 transformers of matter and energy. When we say trans- 

 formers rather than generators we indicate the modern 

 as contrasted with the old-time view. When we say that 

 physiology is the physics and chemistry of living matter 

 we suggest the same significant tendency to bring living 

 and lifeless matter into direct comparison and to recog- 

 nize the same laws as operating in both. The teaching 

 that the same laws do hold sway in the living and the non- 

 living is covered by the term " mechanism "; the earlier 

 view that living things are not fairly to be compared with 

 lifeless, and are to some extent exempt from physical 

 principles and limitations, is expressed by the word 

 " vitalism." We have every reason to believe that the 

 principle of the conservation of energy holds as rigidly 

 for the plant or the animal as for the clock or the loco- 

 motive. This is perhaps the most important generaliza- 

 tion of nineteenth century physiology. 



But while scientific workers are now seeking to analyze 

 the reactions of organisms in accordance with the data 

 furnished by chemists and physicists whose work has 

 been with materials not living, it is probable that the diffi- 

 culties of their problems are better appreciated than was 

 the case a few years ago. Living matter is found to be 

 more complex in structure and more varied in response 



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