PREFACE
The presentation of essential data concerning vitamines to succeeding groups of students has become increasingly difficult with the development of research in this field. The literature itself has assumed a bulk that precludes sending the student to original sources except in those instances when they are themselves to become investigators. The demand on the part of the layman for concise information about the new food factors is increasing and worthy of attention. For all of these reasons it has seemed worth while to collate the existing data and put it in a form which would be available for both student and layman. Such is the purpose of this little book.
It has been called a manual since the arrangement aims to provide the student with working material and suggestions for investigation as well as information. The bibliography, the data in the chapter on vitamine testing, the tables and the subdivision of subject matter have all been arranged to aid the laboratory workers and it is the hope that this plan may make the manual of especial value to the student investigator. The management also separates the details necessary to laboratory investigation from the more purely historical aspects of the subject which we believe will be appreciated by the lay reader as well as the student.
No apologies are made for data which on publication shall be found obsolete. The whole subject is in too active a state of investigation to permit of more than a record of events and their apparent bearing. Whenever there is controversy the aim has been to cite opposing views and indicate their apparent value but with full realization that this value may be profoundly altered by new data.
Since the type of the present manual was set, Drummond of England has suggested that we drop the terminal "e" in Vitamine, since the ending "ine" has a chemical significance which is to date not justified as a termination for the name of the unidentified dietary factors. This suggestion has been generally adopted by research workers and the spelling now in use is Vitamin A, B, or C. It has hardly seemed worth while to derange the entire set up of the present text to make this correction and we have retained the form in use at the time the manuscript was first set up. The suggestion of Drummond, however, is sound and will undoubtedly be generally adopted by the research workers in the subject.
Attempt has been made to cover all the important contributions up to April, 1921. Opportunity has permitted the inclusion of certain data of still later date and undoubtedly other important papers of earlier date will have been overlooked.
It is a pleasure to acknowledge the assistance received in the preparation of the manuscript from Dr. H. C. Sherman, Dr. Mary S. Rose and Dr. Victor La Mer. Their suggestions have been most valuable and greatly appreciated.
WALTER H. EDDY.
Department of Physiological Chemistry, Teachers College, Columbia University, New York City, April, 1921