Notes on scientific research. 109 



work of Tiemann and of Wallach and furnishing a review of the recent development 

 of the technology of the aromatics), deal with the process for preparing odoriferous 

 substances and give furthermore a description of the complex aromatics, their con- 

 stituents, and how the simple and the complex aromatics are obtained artificially. In 

 the chapter "Allgemeine Methoden zur Geivinnung der Riechstoffe" (General methods 

 for preparing odoriferous substances), Hesse enters with particular interest into the 

 distillation of otto of rose in Bulgaria, with which process he is acquainted owing 

 to personal inspection. He describes, inter alia, a duplex still for distilling roses 

 (illustration) furnished by Egrot, of Paris, which shows some handsome and practical 

 details, just like the most of French machinery, but on the other hand, exhibits several 

 serious drawbacks. Various contrivances, e.g., the badly-constructed still-head, show 

 clearly that the French, unlike the German manufacturers, have not taken the trouble 

 to study from a scientific standpoint the process of the steam-distillation or the water- 

 distillation of plants. — In the chapter dealing with the natural complex odoriferous 

 bodies, the more important essential oils, a well as various aromatics of vegetable or 

 animal origin, their hitherto known components, and the analytical methods serving 

 for the examination of these products are enumerated. — The components of essential 

 oils, insofar as the occur as separate trade articles in the industry of aromatics, have 

 been treated in detail by the authors. For instance, the numerous processes for 

 obtaining vanillin, either from the natural products, or by synthesis, are fully dealt 

 with. — In the last chapter, "Kiinstliche Darstellung einfacher und komplexer Riechstoffe" 

 (Artificial preparation of simple and composed aromatics), the authors demonstrate, by 

 various instances, how nearly all the ingredients of natural perfumes can be obtained 

 by chemical means. In addition, many works processes for synthesising these products 

 are communicated. A short compilation of statistical figures illustrating the German 

 import and export of essential oils and aromatics during the last decades and showing 

 the rapid evolution of the German "Riechstojf" industry prior to the War, forms the last 

 chapter of this treatise which is equally will furnished with illustrations and literary notes. 



Towards the end of the 19 th and the beginning of . the 20 th century, the cultivation 

 of medicinal plants in Germany, as well as in other European countries, such as 

 Holland, had gone down seriously. Since the beginning of the Great War, however 

 more especially in the last years, a change has taken place, to which we referred 

 repeatedly 1 ). It was a necessity and an act of material self-respect to cover the demand 

 for medicinal plants from home-grown products. People started again, more especially 

 in Central and Southern Germany, to collect and cultivate drugs on a larger scale. 

 These endeavours were aided by numerous societies, e.g., the "Committee for propagating 

 the collection and cultivation of medicinal and economical plants by Government 

 measures" (Ausschufi zur staatlichen Forderung der Sammlung und. des Anbaus arzneilich, 

 icirtschaftlich und technisch verivertbarer Pflanzen) at Dresden, the "Hortus-Society" and 

 the "Society for the promotion of the cultivation and collection of medicinal and 

 aromatic plants" (Gesellschaft zur Forderung des Sammelns und des Anbaus von Geiviirz- 

 pflanzen) in Bavaria, and by the German Pharmaceutical Association (Deutsche Pharma- 

 zeutische Gesellschaft) of Berlin. However, these endeavours and suffered opposition 

 from various quarters. One of the objections made seemed to be somewhat justified 

 insofar that it was considered unwise to enlarge the area used for drug cultivation 

 in stead of cultivation of victuals and fodder, or of important vegetable raw-materials 



*) Cf. Reports 191 7, 110; 1918, 78. 



