General Considerations: Methods for the Standardization of Biological Stains: Part I

This is the introduction to a series of papers giving the assay methods employed in the testing of dyes submitted to the Commission on Standardization of Biological Stains. These methods are used in determining whether or not to allow the sale of any particular batch of dye as a certified stain. The present paper takes up general considerations, discussing the relative merits of various analytical methods designed both for qualitative and quantitative analysis. The advantages of determining light “absorption ratios” for qualitative purposes, and of titanous chloride reduction for quantitative purposes are pointed out. It is further indicated that in spite of all the refinements that have yet been made in chemical and optical methods of analysis, great weight must be placed on biological testing in determining the quality of any given sample.