Detection of dulcin and saccharin by optical methods

sf this tree apparently are yet aware that the gum has any commercial I-alue. The properties and composition of this “ sweet gum,” a< it is called, are simiilar to those of oriental storax. obtained from Cina tree (~i~z~ida~&r orir:nta’Zis) which grows in Xsia Minor. namic acid and cinnamic alcohol are two of its valuable components. Because the war curtailed the supply of the imported product, the I_‘. S. Forest Products Laboratory this season undertook some coiiperative experiments to develop methods of gathering “ sweet Although the yield of gum from storax.” guni ” or “ American each tree is not large, a price of $2 or more a pound has made its collection attractive to many individual operators and a considerable quantity has been put on the market. ‘fhc laboratory experiments will be completed in November. and it is hoped that they will provide some co.st data which will indicate to what extent “ American storas ” can profitably compete with the foreign product when normal conditions return. Detection of Dulcin and Saccharin by Optical Methods. A. .\~:~<.~rlan~. (Menz. Acad. Roy. d. Sciences de LiPgr, vol. x, p. 4.)Dulcin and saccharin are liable to be used in many beverages as substitutes for sugar. They are usually detected by color tests, hut the author of this paper gives an account of their detection by the microscopic examination of the crystals from an ethersolution. These optical methods are becoming of increasing importance. They depend on the use of modified light, especially polarization. Very small crystals can be identified accurately. The method, as is well known, has been long applied in mineralogy in the examinations of rock-sections. The microscopic equipment is complicated and expensive. The United States I)epartment of Agriculture is conducting special researches along this line, especially in connection with the detection of the alkaloids. H. L. The

Production of Large Perfect Crystals. R. W. MOORE. Chew. Sot., vol. xli, p. 1060, IgIg.)-After briefly reviewing the literature of the subject, describes a method by which ver\T large and perfect crystals can be obtained from solution. It fs ~vell known that many fine crystals are found in nature, but these are usually so involved in the matrix as to prevent separation without injury and are often unequally developed in some planes. Moore required some perfect crystals of sodium-potassium tartrate and searched through several tons of the salt finding hut little material. After examining the published methods, he devised a plan by which a saturated solution of the substance is made at a temperature between 35” and 40’ C. This is heated a fen- degrees higher and then filtered. The temperature must be kept slightily above the saturation temperature. Small crystals of the salt, termed “ seed-crystals,” are placed in a jar, the solution (J. ~1~1.