This is carried for years hidden in a mother's bosom.

Fathers, brothers, sisters, and friends, often, but by no means so universally, have duplicates of it.

The wedding-ring conveys a right to one; alas, if none is given with it! If nature or accident has put one of these keys into the hands of a person who has the torturing instinct, I can only solemnly pronounce the words that Justice utters over its doomed victim, -- THE LORD HAVE MERCY ON YOUR SOUL! You will probably go mad within a reasonable time,--or, if you are a man, run off and die with your head on a curb-stone, in Melbourne or San Francisco,--or, if you are a woman, quarrel and break your heart, or turn into a pale, jointed petrifaction that moves about as if it were alive, or play some real life-tragedy or other.
Be very careful to whom you trust one of these keys of the side-door.

The fact of possessing one renders those even who are dear to you very terrible at times.

You can keep the world out from your front-door, or receive visitors only when you are ready for them; but those of your own flesh and blood, or of certain grades of intimacy, can come in at the side-door, if they will, at any hour and in any mood.