In the preface to the first volume of the second edition it was pointed out that the individual essential oils would be dealt with in the second volume. As, however, in the course of compilation it was found that the matter had grown to more than twice its bulk, as compared with the first edition, and could not, therefore, be comprised in a single volume, it was deemed advisable to proceed to a further subdivision by allowing the manuscript, as far as it was ready, to appear as second volume. The inner arrangement remains unaltered. As was the case with the first edition, the essential oils are enumerated in the order in which the respective plants appear classified by A. Engler in his "Syllabus der Pflanzenfamilien". This second volume presents the oils up to and including those of the Zygophyllacese and of part of the Rutacese. A third volume will bring the work to its conclusion.

Mlltltz near Leipzig, June 1916.

E. Gildemeister.