Talking of constitutional melancholy, he observed, "A man so afflicted, Sir, must divert distressing thoughts, and not combat with them."
Boswell: "May not he think them down, Sir?"
Johnson: "No, Sir. To attempt to think them down is madness. He should have a lamp constantly burning in his bed chamber during the night, and if wakefully disturbed, take a book, and read, and compose himself to rest. To have the management of the mind is a great art, and it may be attained in a considerable degree by experience and habitual exercise.."
Boswell: "Should not he provide amusements for himself? Would it not, for instance, be right for him to take a course of chymistry?"
Johnson: "Let him take a course of chymistry, or a course of rope-dancing, or a course of any thing to which he is inclined at the time. Let him contrive to have as many retreats for his mind as he can, as many things to which it can fly from itself."
Samuel Johnson
James Boswell: Life of Samuel Johnson