Recipe............................

After the age of eighty she found she had some difficulty in getting to sleep, so she habitually spent the hours from midnight to 3:00 A.M. in reading popular science.  I do not believe that she ever had time to notice that she was growing old.  This, I think, is the proper recipe for remaining young.  If you have wide and keen interests and activities in which you can still be effective, you will have not reason to think about the merely statistical fact of the number of years you have already lived, still less of the possible brevity of your future.

Bertrand Russell, discussing his maternal grandmother in his essay, How To Grow Old.  Published here