He talks of how the mind can be likened to a garden in this paragraph:
A man's mind may be likened to a garden, which may be intelligently cultivated or allowed to run wild; but whether cultivated or neglected, it must, and will, bring forth. If no useful seeds are put into it, then an abundance of useless weed seeds will fall therein, and will continue to produce their kind.
I think I will take heed of this message! I will weed out the neglected areas of my mind and put some useful seeds into it. I will start by reading 'As a Man Thinketh'. It is so hard to believe that his wise words were written so many years ago and yet are still relevant today.