A Comment on Calculation of Feulgen-DNA Content Determination by Microspectrophotometry

The relative values of DNA contents of lymphocyte nuclei were estimated by the scanning method of Feulgen microspectrophotometry. The caluculation were made by the following two formulas Q_a = ∫| x | f(x)dx (a) Q_b = r/2 ∫f(x)dx (b) where Q_a and Q_b : the relative value of DNA content f(x) : the curve obtained actually tracing the nuclear along the diameter with the spot light |x| : a distance from the center of the nuclear diameter r : the radius of the nucleus. The values were calculated from the areas surrounded by the extinction curves in the formula (b), and from the volumes of the rotating body of the extinction curves in the formula (a). The calculation from the formula (a), which was recommended by Seno and Utsumi, has been proved very useful in minimizing the distribution errors and the Schwarzschild-Villiger effect. But it is so cumbersome in its practical use that a simpler and dependable method is desirable. We have found that the formula (b) fits for this purpose and the values calculated from it is fully reliable as a result of statistical analysis.