The four who are at the same bridge table.

Partners or fellow-players in any game.

At a dance, when an invitation has been asked for a stranger, the friend
who vouched for him should personally present him to the hostess. "Mrs.
Worldly, this is Mr. Robinson, whom you said I might bring." The hostess
shakes hands and smiles and says: "I am very glad to see you, Mr.
Robinson."

A guest in a box at the opera always introduces any gentleman who comes to
speak to her, to her hostess, unless the latter is engrossed in
conversation with a visitor of her own, or unless other people block the
distance between so that an introduction would be forced and awkward.

A newly arriving visitor in a lady's drawing-room is not introduced to
another who is taking leave. Nor is an animated conversation between two
persons interrupted to introduce a third. Nor is any one ever led around a
room and introduced right and left.

If two ladies or young girls are walking together and they meet a third
who stops to speak to one of them, the other walks slowly on and does not
stand awkwardly by and wait for an introduction. If the third is asked by
the one she knows, to join them, the sauntering friend is overtaken and an
introduction always made. The third, however, must not join them unless
invited to do so.

At a very large dinner, people (excepting the gentlemen and ladies who are
to sit next to each other at table) are not collectively introduced. After