CHAPTER XXIX 

 SOME MATTERS OF HYGIENE 



A chapter on the Hygiene of the Nervous System has 

 found a place in this book and also one on the Hygiene of 

 Nutrition. Other suggestions regarding the right use 

 of the body have been dropped from time to time. It 

 may be well in conclusion to assemble some of the funda- 

 mental principles in the form of a summary. When this 

 is undertaken it is a distinct advantage to have all the 

 topics which we have treated as a background to cor- 

 relate our hygiene with our physiology. 



Vitalism and Mechanism. Living matter is sharply 

 distinguished in many ways from lifeless. The con- 

 trasts are so evident that men of science formerly be- 

 lieved that very different principles must be effective 

 in the two states. Organisms were supposed to tran- 

 scend some of the limitations of inorganic bodies. The 

 teaching that they are thus superior to what are called 

 the laws of nature is known as Vitalism. The contrary 

 doctrine, that they are strictly limited by these laws, 

 that they are machines transforming energy which they 

 neither create nor destroy, is called Mechanism. 



We have seen that the experiments made in labora- 

 tories for the study of metabolism show that animals and 

 men are rigidly subject to the principle of the conserva- 

 tion of energy. The modern tendency has been to em- 

 phasize this subjection to fixed limitations, and it is certain 

 that experimental progress has been based almost wholly 

 upon faith in its validity. Our objective studies must be 

 conducted upon organisms or parts of organisms in the 

 hope that we may find uniform responses to the condi- 

 tions we establish. If we cannot find the regularity of 



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