PREFACE. 



The researches in this book are an amplification of the investigation on 

 the metabolism of diabetes mellitus instituted in this laboratory in 1908. The 

 experimental evidence has reached such a point that certain fundamental 

 questions can be adequately discussed; many others are still in the process of 

 investigation. 



The complicated nature of calorimetric experiments, the urine analyses, 

 and the respiration experiments have made this study possible only through 

 the active and hearty cooperation of our associates. Most of the respiration 

 and calorimeter experiments were made either by Mr. Thorne M. Carpenter 

 or Mr. L. E. Emmes. The urinary analyses were made in part in the Nutri- 

 tion Laboratory and in part in the private laboratory of one of us (E. P. J.), 

 with frequent determinations in both places as controls. As before, the deter- 

 minations of /5-oxybutyric acid were made by Dr. F. H. Stanwood in the Lab- 

 oratory of Biological Chemistry of the Harvard Medical School. The routine 

 clinical urinary examinations were made by Miss Elsie Newman, while the 

 total nitrogen determinations and the sugar determinations by the copper- 

 reduction method were made in the Nutrition Laboratory by Miss Alice 

 Johnson and Miss E. B. Babcock. 



For the determinations of the "retention of alkali" by the kidneys in the 

 case of a normal individual studied in connection with this report we are 

 indebted to Dr. Gerald Blake. 



Nutrition Laboratory of the Carnegie Institution of Washington, 



Boston, Mass., June 14, 1912. 



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