From The Arthur Conan Doyle Encyclopedia
Fanny Robinson was flighty; she played the giddy ox—I mean, heifer.
When her younger sister wouldn’t get out of bed to heat her curling-irons in the candle, she said, “Mary, you’re a little beast.”
She seemed to think that younger sisters were born to fasten up elder sisters’ boots, to go to buy chocolate creams for them at all hours of the day, and to be pinched, ad libitum, on the nearest square inch handy.
Her pa and her ma and her maiden aunts got tired of this.
The girl hadn’t got a single good quality.
She grew more and more discontented.
In the last century, “whacky-whacky-whack” was not merely the humorous subject of a song. It was a recognized institution.
Bad girls use aerated oil for their hands these days.
Then they had strap oil. We live in a humane age. Naughty girls are no longer made to squeak when they are discontented with their homes.
They take to writing three-volume novels, going on the stage and wearing not-too-voluminous skirts and so on.
Fanny Robinson’s pa suspected her of meeting constantly an objectionable, dissipated bloke with no property.
He wanted to find out all about her.
You have no idea how clever amateur detectives are nowadays. He went and called on W. Sherlock Holmes. He told him his story.
“A most interesting case,” said Sherlock Holmes. “If your daughter is absent from home, I’ll just walk back with you.”
They walked back.
Sherlock Holmes walked straight into the girl’s bedroom. He walked straight up to her looking-glass and wiped it with his pocket-handkerchief, which he placed against his nose.
Just then Miss Fanny came in.
“What are you doing here?” she shrieked, indignantly.
Sherlock Holmes calmly cleaned out his briarroot with a stray stay tag, filled it with the strongest shag and lit it with a stray curling paper.
“Allow me to say, Miss Robinson,” said he, “that you are a very vain girl—that you are in the habit of using your short absences to meet a dissipated young man who kisses you frequently—you meet him at least half a mile from home.”
“Who told you?” sobbed the baffled female.
“The pocket-handkerchief,” said Sherlock Holmes. “In the pocket-handkerchief that I have wiped the looking-glass with is a perfect film. You must have looked in the glass very often. That shows your vanity. You must have breathed very hard, or the glass would not have had that film covering it, which I wiped off. That proves that you were in a hurry, and that the person you met was some distance off. There is a strong smell of alcohol on the film, which shows that you had been kissed severely by a man who had brandy and soda very early in the morning. Your hurried breathing carried the alcohol to the mirror.”
The girl had betrayed herself.
Moral.—You never, under any circumstances, can be so bally clever as to outwit an amateur detective.
(Apologies to Conan Doyle, the man had no right to call himself Sherlock Holmes.)