Recent progress in the staining of DNA-aldehyde in cell nuclei.

The paper is a review of studies on Feulgen staining of nuclear DNA. For convenience, the paper is split into several sections, such as (a) the characteristic of the dyes used for the manufacture of Schiff reagent (b) preparations of Schiff reagent (c) fixation of the material (d) hydrolysis (e) staining with Schiff reagent (f) Schiff-type dyes and (g) use of Schiff-type dyes in quantitative cytochemistry. Barring the section on preparation of Schiff reagent that includes the classical methods, all other sections contain a comprehenside account showing progress made during the last 15 years. Under each section interpretations of new findings as far as possible, and in the section on staining with Schiff reagent, new approaches to its study have been presented. The section on Schiff-type dyes includes dyes with and without primary amino group.