The occurrence, isolation, structure and properties of red oak lignin.

This introduction is divided into two parts: a brief Historical Survey of Lignin Chemistry and a General Section in which are discussed certain aspects of plant chemistry and related subjects which have a direct bearing on the problem at hand. The historical survey is not intended to be an inclusive review of the findings of the many workers in the field during its long and devious development. Several reviews of this type are at present available; notable are: for the older work, that of Phillips (1), and more recently, that of von Wacek (2). The present survey is intended to outline the changing viewpoints from which the problem of lignin isolation has been attacked and to show how inherent limitations to the results obtainable arose from the methods of lignin isolation employed