The Chemistry of the Terpenes.

The production of a good English translation of Heusler's book on the terpenes will be welcomed by many English-speaking chemists, and the fact that in the translation the rapidly expanding subject matter has been brought up to date will, of course, make this edition more valuable than the original. Heusler's work was originally published as a part of a "Handworterbuch" of chemistry, with the purpose of collecting the scattered material of this important and interesting branch of organic chemistry. It consists, therefore, of an introductory chapter with general considerations, followed by a classification and description of the members of both the terpenes and the closely related compounds. While probably as much space as is warranted is given to the matter of properties and preparation of the innumerable derivatives, the worker will undoubtedly find its greatest use as a classified and intelligent directory to the original papers from which it is