CHAPTER XIV 



SOURCES OF KNOWLEDGE 



THE foregoing chapters embody many statements of 

 principles and facts which have been made positively 

 and without modification. To quite an extent these 

 are based upon the conclusions of scientific men, that 

 is, conclusions which have been reached after such study 

 of the problems involved as is competent to secure ac- 

 curate information. In some cases this study has been 

 severe and long continued, having been carried on 

 by the use of methods and apparatus capable of the 

 most precise measurements. Moreover, in the investi- 

 gations of science an effort has been made to pro- 

 ceed logically, so that the results attained shall not 

 be fallacious. Notwithstanding the fact that a great 

 deal of our knowledge is the result of an earnest and 

 impartial search after truth, under conditions espe- 

 cially favorable to its discovery, many persons are 

 disposed to give more credit to the traditions and 

 conclusions of practice than to the carefully prepared 

 verdicts of science. It may not be out of place, 

 therefore, to present in this connection some of the 

 considerations and methods which have to do with 

 the acquisition of knowledge concerning animal nutri- 

 tion, for this may aid us to appreciate the value of 



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