PREFACE 
The experimental evidence secured in connection with this research was 
made possible only through the active co-operation and personal interest of 
the gentlemen who acted as subjects. Our thanks are due to Mr. Kurt H. 
Arndt, Mr. J. J. Currie, and especially to Mr. H. L. Higgins and Mr. J. E. 
Fitzgerald, all of the laboratory staff. Mr. Fitzgerald furthermore assisted 
in practically all of the experiments on others than himself. 
We are indebted to Dr. W. G. Anderson, Director of the Yale University 
Gymnasium, not only for the physical measurements on some of our subjects, 
but likewise for his co-operation in certain of the tests. 
The extraordinary interest and fidelity to the routine exhibited on the 
part of the professional subject, Mr. Melvin A. Mode, should not pass without 
special comment. It would have been impossible to conduct a series of experi- 
ments of this type without the intelligent co-operation of the subject. 
The complicated tables in the report have received the careful prepara- 
tion of Mr. W. H. Leslie, and the entire manuscript has had the editorial 
supervision of Miss A. N. Darling. To all of these co-workers we wish to 
express our thanks. 
Nutrition Laboratory, Carnegie Institution op Washington, 
Boston, Mass., April 12, 1913. 
