— 109 — 



the progress which has been made in the investigation of essential 

 oils since the first appearance of the book in 1899. The enormous 

 output of publications dealing with essential oils has necessitated a 

 considerable enlargement of the book, which finds expression in the 

 growth of the volume up to 546 pages, as compared with 411 pages 

 in the first edition. The work concerns itself chiefly with laboratory 

 practice, and for this reason it deals only briefly with the chemistry 

 of the various constituents and the method of preparation of the oils, 

 while on the other hand a great deal of space is devoted to the 

 description of the properties and to the testing of oils. The leading 

 commercial oils in particular are discussed at great length, special 

 stress being laid upon the detection of adulterations and upon the 

 eventual quantitative determination of the constituents, which are of 

 value in determining the value of each particular oil. The book con- 

 tains, for example, detailed information with regard to the determina- 

 tion of citral, cinnamic aldehyde 1 ), eugenol, cineol, etc. A special 

 chapter is devoted to artificial perfumes. As an appendix to the book 

 there is a chart indicating the specific gravity, rotation, index of re- 

 fraction and composition of the principal oils, and another showing the 

 requirements of the various Pharmacopoeias with regard to essential oils. 

 Although in certain details we are of different opinion as Mr. Parry, 

 his book must nevertheless be pronounced as, upon the whole, a sound 

 guide for the chemist who is engaged in the investigation of essential 

 oils, and in its new dress it ought to add fresh friends to its old circle. 



In a brochure entitled Les constituants des Huiles Essentielles (Paris, 

 Alph. Isnard) the author, Marcel Viard 2 ), treats his subject in a 

 concise, summary manner. After a discussion on the general properties 

 of essential oils, with consideration, in parts, of the effect thereon of 

 their chemical composition (which discussion may be regarded as a sort 

 of introduction), Viard first proceeds to draw a general outline of the 

 methods used in the separation of the most important constituents of 

 the oils, and then refers specially to the separate bodies, which he groups 

 according to their chemical properties. In the case of each combination 

 reference is made to the oils which serve as the crude material for its 

 preparation, and methods are given for the quantitative determinations 

 of the oils, insofar as any are known, as well as for the manner of 

 isolating the constituents of the various oils. In the case of the more 

 important combinations there are . also data for the purification of the 

 crude product. Viard further gives data forjudging the various bodies, 



*) Parry calls our cassia flask "Hirschsohn flask". Compare Report November 

 1908, 92. 



2 ) We here return thanks to Mr. Viard for courteously sending us a copy of 

 his pamphlet. 



