Study on Hydrolysis gor Feulgen Microspectrophotometry

In the present study, examinations of Feulgen hydrolysis were carried out by the microspectrophotometric measurement of the relative DNA contents in lymphocyte nuclei. Smears of thymus of male mice, 2-month old, were made. The smears were air-dried for at least 1 hour, fixed in methanol-formalin-acetic acid mixed 85 : 10 : 5, in Carnoy's solution or in formalin vapor for 30 minutes, and subjected to the Feulgen-staining procedure. Feulgen hydrolysis was performed either in 1 N HCl at 60℃ in a constant temperature water bath or in 5 N HCl at 25℃ (±3℃). After washing, smears were stained in decolorized basic fuchsin for 3 hours, and rinsed three times with SO_2 for 15 minutes and once tap water for 5 minutes. The relative DNA content was measured in 10 to 20 small lymphocytes from each smear by microspectrophotometry at 560 mμ by the scanning procedure.