AUTHOR'S PREFACE 



THE object with, which, the following pages have been written 

 is to present to the reader a broad view of the subject of nutrition 

 in the light which recent investigations have shed on the problems 

 connected therewith. 



Since the publication of the volumes dealing with Chittenden's 

 views on the protein requirements of the body, a very con- 

 siderable amount of investigation has been quietly going on. 

 Sufficient time has now elapsed, since his first onslaught on the 

 generally accepted opinions held with regard to the level of 

 nitrogenous interchange within the body necessary for the 

 maintenance of a healthy man of average weight and doing a 

 moderate amount of work in health and in a state of efficiency, 

 to permit of definite conclusions being arrived at. 



It is meet, therefore, that the stage now arrived at in the 

 determination of the ideal form of the dietary of mankind 

 should be placed on record. Such a record, the author hopes, 

 will be found in the matter set forth under the following chapters. 



In the present volume the author has made use of the observa- 

 tions and investigations of a great many of the more important 

 recent publications on the subject, and has attempted to show 

 that the weight of evidence is entirely against the great reduc- 

 tion of the protein content and caloric value of the dietaries of 

 mankind so strongly advocated by Chittenden. 



Recent investigations by different research workers have 

 shown that it is possible to reduce very considerably the quantity 

 of protein necessary to maintain an animal in nitrogenous equi- 

 librium, when the particular nitrogenous compounds required 

 by that animal only are given in the food. In fact, at the 



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