The greatest care should be exercised in giving letters of introduction. They should never be given unless one is well acquainted with the standing and character of the person to be introduced. Some people, because they have not the moral courage to refuse a direct request, will write such a letter for a person whom they hardly know and for whose character they cannot vouch. They are then forced either to leave the friend to whom they have given the letter to run the risk of making an undesirable acquaintance, or they must write privately to say they have given the letter, but that their friend should perhaps find out more about the bearer, as he or she is not very well known to them. Either course is a grave unkindness to the friend to whom the letter is given, and may place him in an embarrassing and painful position. If he receives no warning he may introduce a wholly undesirable person to his own circle of acquaintance. If, on the other hand, he receives the warning, he naturally acts upon it, and consequently all the unpleasantness of declining an acquaintance is thrust upon him. It is therefore always better to refuse to give such a letter unless one knows the person to be introduced and can vouch for him or her in every way. A letter of introduction should be strictly confined to the presentation of the person on whose behalf it is written. Nothing personal or private should be mentioned, and it should be as brief and as concise as possible. It is handed or sent to the bearer in an open envelope addressed to the person to whom it is to be presented. On no account should it be given or sent in a closed envelope, since that suggests that something has been written by the writer which he does not wish the bearer to see.
