ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

 prepared and signed by themselves, are forwarded promptly to the editors. 

 The abstracts should conform in length and general style to those appearing 

 in this issue. 



CRYSTALLOGRAPHY. — The application of optical methods of identifi- 

 cation to alkaloids and other organic compounds. Edgar T. Wherry. 

 U. S. Dept. Agr. Bull. 679. Pp. 9. 1918. 

 The value of optical methods for identifying crystalline substances 

 is pointed out, and methods for the study of substances such as alkaloids 

 are outlined. The observations recommended are: I. In ordinary 

 hght: Color, habit, angles, cleavage, and refractive indices; detailed 

 directions with respect to the last are given, including the preparation 

 of special immersion liquids of solutions of potassium-mercuric iodide, 

 which are required for certain alkaloids. 11. In parallel polarized light: 

 extinction, double refraction, and sign of elongation. III. In conver- 

 gent polarized light: class, sign, and dispersion. The details of manip- 

 ulation are illustrated by describing the procedure in the case of 

 cinchonine . E. T. W. 



CRYSTALLOGRAPHY. — The identification of the cinchona alkaloids hy 

 optical-cry stallographic measurements. Edgar T. Wherry and 

 Elias Yanovsky, Journ. Amer. Chem. Soc. 40: 1063-1074. 

 1918. 

 The methods described in the paper previously abstracted were 

 applied to carefully purified cinchonine, cinchonidine, quinine, and 

 quinidine, crystallized from alcohol and from benzene. The optical 

 properties of these are presented in a standard formal description and 

 then tabulated in columns to show the differences. Determinative 

 tables based on the properties measured are given. The results of 

 crystallization of mixtures are also described, and a method for the 

 examination of a medicinal preparation containing these alkaloids 

 outlined. E. T. W. 



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