The several extracts from the letters of Drs. Kellogg and Dewey; the statement relative to an endurance-test made on the author's fiftieth birthday, on a bicycle in France, volunteered by Edward W. Redfield, last year's Medal-of-Honorist at the Pennsylvania Academy of Fine Arts, Philadelphia, as well as medalist of last Exposition Universale, Paris; are appreciated and accepted for the subject they endorse; and, as before stated, are entirely impersonal. Instead of using dumb animals for test subjects and getting their unwilling, and sometimes abnormally deranged, participation, the author takes pleasure in submitting to the tests himself, and is thus able to state "symptoms" and "feelings" more accurately, perhaps, than any dog could do. Were vivisection necessary the author would willingly submit to that inconvenience also; but thanks to the skill of a Pawlow, and the ingenuity of a Bowditch coupled with the patience and persistence of a Cannon, as fully related in the "A.B.-Z.," we not only get the economic results but we are able to know and even see some of the "reasons for things" as well. Interesting testimony and comment relative to the present study will be found at the end of the volume in communications from Commandante Cesare Agnelli, Clarence F. Low, Esquire, Baron Randolph Natili, and one of unusual suggestiveness, as evidence of the need of further study of nutrition, from Dr. Hubert Higgins of Cambridge, England. MILITARY-SCIENTIFIC COÖPERATION With the evidence and interest just outlined, it was not difficult for the author to enlist the coöperation of Surgeon-General O'Reilly of the United States Army and the endorsement of General Leonard Wood for larger investigation of the subject. These officers, both of them surgeons and medical doctors, had supported the militant-martyr-scientist, Dr. Major Walter Reed, in his great sanitary accomplishment; had fought yellow fever to a finish together in Cuba; had traced its spread to a specific cause; and were thereby encouraged to tackle even so common and powerful enemies as Indigestion and Mal-Assimilation. The investigation now in progress at Yale University, under the direction of Professor Chittenden and under the fostering auspices of the Trustees of the _Bache Fund_, which is administered by the National Academy of Sciences, and other contributed support, is a Militant-Scientific campaign which will not cease until we know as much about human nutrition, at least, as we know about the nutrition of our domestic animals. In this little book, however, is an account of the first distress and war cry, (to appropriate an expression of the Salvation Army), and while the workers in Science may take a considerable time to make observations and investigate the "reasons for things," the underlying claims herein stated will, it is believed, ultimately be established as fundamental facts of both Hygiene and Physiology.