Abstract
In rats, the cerebrum, cerebellum, diencephalon and brain-stem were studied for their nucleic acid content. The values were compared between mature and descrepit rats. It was revealed that as for the decrease in RNA content by decrepitude the diencephalon ranked first, followed by the brain-stem and cereb-rum in order, but the cerebellum showed almost no decrement. In any portion of the brain difference of DNA content due to age was not recognized.
