The perfect hostess will see to it that the works of male and female authors be properly separated on the bookshelves. Their proximity unless they happen to be married should not be tolerated.Unlike many other, indeed most, popular quotes, it is unvariably attributed to a single source, named and dated, varying only in unimportant details: lady Gough in her 1863 book Etiquette, or at least a book by her about etiquette.
Sounds like fantastic reading! What other gems could be hidden there?
However, if lady Gough (of which there have been a couple, before and after 1863) ever wrote such a book, there doesn't seem to be a trace of it, except for the quote above. Not only has nobody found any other quotes in it worth mentioning, but no library seems to keep a book by the author on the given subject, and nobody seems to have mentioned it in text — until 1929.
Lady Gough, distinguished blue-nose of England, wrote a book on Etiquette in 1863; and on page 80 I find this paragraph [...]- Robert Ripley, quoted in New York Times February 17, 1929
Robert "Believe It or Not!" Ripley is not best known for truthfullness, as the strange case of "Neils Paulsen" demonstrates. (Apart from the obvious, the name looks more like mispelt Danish than Swedish.) If he invented the peculiar advice from a book that didn't exist it wouldn't be too surprising. It would also explain why he bothered to mention that the quote was found on page 80; an odd detail in a blurb like this, but a classic method to improve a lie.
That is, of course, unless someone can show a copy of the book in question, or at least prove that it has ever existed. Or find a similar piece of advice in another source from the period.
There were indeed plenty of books on etiquette in the 19th century. Like Hints on Etiquette by "Agogos", pseudonym for Charles William Day. Unlike lady Gough's unlikely volume, this one existed very much: First published in London in 1834, it was printed in 28 editions for the next two decades. As a sample of it's wisdom, here's some advice for conversating with certain American women:
With American ladies of the second class, there is a great proneness to construe the commonest expressions and words into having indelicate meanings — to realize, indeed, the sailor's axiom of being "nasty nice" or virtually to embody Swift's biting truism, that "the nicest people have the nastiest ideas." The truth is, that, in America, female delicacy has become morbid, and has gone beyond that wholesome propriety of feeling, which distinguishes between an intended grossness, and a word which is fully understood to have no other meaning than that which it expresses. Extreme delicacy borders closely on indelicacy, and a gentleman, especially an Englishman, is sometimes compelled to rack his brains in order to discover how that which he has said can be so distorted from its true meaning; and the discovery, when made, however it may amuse him at its ingenuity, rarely elevates the lady in his opinion, but rather astonishes him at the grossness of sentiment which it implies, and which must have existed in her mind before she was gauche enough to let it appear.- Hints on Etiquette, chapter XI "Conversation"