Abstract
In this paper the methods are given which are used in determining whether to approve the sale of certain dyes of the fluorane group as certified biological stains. The methods have been worked out by the Commission on Standardization of Biological Stains in cooperation with the Color and Farm Waste Division, Bureau of Chemistry and Soils, U. S. Dept. of Agriculture. The dyes for which the methods are given in the present paper are: Fluorescein, eosin yellowish, ethyl eosin, eosin bluish, erythrosin, phloxine B, and rose bengal. For each of these dyes methods are given under the following headings: (1) identification or qualitative examination; (2) quantitative analysis; and (3) biological tests.