When you are introduced to some one for the second time and the first occasion was without interest and long ago, there is no reason why you should speak of the former meeting.

If some one presents you to Mrs. Smith for the second time on the same occasion, you smile and say “I have already met Mrs. Smith,” but you say nothing if you met Mrs. Smith long ago and she showed no interest in you at that time.

Most rules are elastic and contract and expand according to circumstances.  You do not remind Mrs. Smith of having met her before, but on meeting again any one who was brought to your own house, or one who showed you an especial courtesy you instinctively say, “I am so glad to see you again.”

=Including someone in conversation without an introduction=

On occasions it happens that in talking to one person you want to include another in your conversation without making an introduction.  For instance:  suppose you are talking to a seedsman and a friend joins you in your garden.  You greet your friend, and then include her by saying, “Mr. Smith is suggesting that I dig up these cannas and put in delphiniums.”  Whether your friend gives an opinion as to the change in color of your flower bed or not, she has been made part of your conversation.

This same maneuver of evading an introduction is also resorted to when you are not sure that an acquaintance will be agreeable to one or both of those whom an accidental circumstance has brought together.

=Introductions unnecessary=

You must never introduce people to each other in public places unless you are certain beyond a doubt that the introduction will be agreeable to both.  You cannot commit a greater social blunder than to introduce, to a person of position, some one she does not care to know, especially on shipboard, in hotels, or in other very small, rather public, communities where people are so closely thrown together that it is correspondingly difficult to avoid undesirable acquaintances who have been given the wedge of an introduction.

As said above, introductions in very large cities are unimportant.  In New York, where people are meeting new faces daily, seldom seeing the same one twice in a year, it requires a tenacious memory to recognize those one hoped most to see again, and others are blotted out at once.

People in good society rarely ask to be introduced to each other, but if there is a good reason for knowing some one, they often introduce themselves; for instance, Mary Smith says: 

“Mrs. Jones, aren’t you a friend of my mother’s?  I am Mrs. Titherington Smith’s daughter.”  Mrs. Jones says: 

“Why, my dear child, I am so glad you spoke to me.  Your mother and I have known each other since we were children!”

Or, an elder lady asks:  “Aren’t you Mary Smith?  I have known your mother since she was your age.”  Or a young woman says:  “Aren’t you Mrs. Worldly?” Mrs. Worldly, looking rather freezingly, politely says “Yes” and waits.  And the stranger continues, “I think my sister Millicent Manners is a friend of yours.”  Mrs. Worldly at once unbends.  “Oh, yes, indeed, I am devoted to Millicent!  And you must be ——?”