The entire subject of beriberi has been in hopeless confusion for many years. The ordinary reader who is searching for information on the subject is simply appalled by the mass of literature that has been accumulated, and without special study is quite unable to sift the wheat from the chaff, or the rice from the polishings. And when the reader turns to the recognized standard medical text-books he finds that the authors simply state that the etiology and treatment of beriberi are uncertain, or that when they do furnish answers on these questions, the solutions offered are almost as various as the authorities.<br><br>It has been the fortune of the author to be engaged in the experimental study of the etiology of beriberi during the past two years, and in the course of this work he has been obliged to sift the evidence presented in the literature. It is now his hope that a critical review of the entire subject will be of material assistance in clarifying the present confusion.<br><br>It is particularly desirable that this should be done at this time for the reason that we may justly claim that within the past few years we have mastered the subject from a practical point of view. We are now in a position to prevent the disease in any community that can and will follow our advice just as surely as we can prevent smallpox and yellow fever.<br><br>From a scientific standpoint, the advances made in the study of beriberi in recent years are almost as satisfactory. The main question as to the etiology of beriberi has been settled, and the key to the solution of the minor puzzles that yet remain is in our hands. Moreover, the facts that have been discovered with regard to beriberi have thrown a great light upon other diseases, such as scurvy, and have revolutionized our ideas with regard to the metabolism of the body, although the text-books on physiology have not yet appeared to notice this.<br><br>In spite of the great importance of this work, there is, so far as I am aware, no book on beriberi in the English language of a later date than Braddon's (1907), which, moreover, deals with the subject from an entirely different viewpoint. It would appear, therefore, that there is a good opportunity for another book on beriberi.