The material for this experiment was brain tissues of normal rabbits whose cisterna magna had been previously injected with ³²P and obtained by decapitation after a fixed period of time. Decomposing phosphoric acids in the brain tissues into various fractions by Schneider's method, the author pursued the mode of ³²P migration in each fraction from the standpoint of time elements; and obtained the following results.
Shortly after the injection ³²P is found to have migrated to acid-soluble fractions in the greatest amount but only little to other fractions. However, with lapse of time after the injection the rate of ³²P migration to the acid-soluble fractions decreases, especially markedly so to inorganic phosphoric acid fractions, whereas the rate of ³²P migration to phospholipid, nucleic acid, and phosphoprotein fractions gradually increases.
Moreover, for a short period after ³²P injection the rate of ³²P migration to various fractions fluctuates markedly, but after 24 hours such a fluctuation in each fraction seems to diminish, apparently indicating a certain degree of stabilization.