Lillian Eichler,
Book of Etiquette, Volume 2, Part 4…
(1921)
“ To welcome a man in one's room is to break a convention that has many years of strict practice to uphold it. It is a serious blunder in hotel etiquette. If a gentleman calls upon a lady at a hotel, whether it be in a business or social capacity, and finds that she is not in, he may leave his card with the desk clerk to be forwarded to her. It is necessary, however, that he write on the back of the card for whom it is intended; for the memories of desk clerks are not quite as retentive as some of us think they are, and there is a possibility of the card being sent to the wrong guest. ”
