"Watson, as your friend I feel it is my duty to advise you not to ask Mrs. Hudson to lend you her jar of cold cream."

Startled, I dropped my pen. "Why Holmes, this is extraordinary! I've said nothing about cold cream!"

"Oh, it's quite elementary, I assure you. First, when you arrived this evening you were slightly flushed, your right palm showed crimson blotches, and there were flecks of birch twig on the sleeve and collar of your shirt. From this, I deduced that you had recently chastised someone's posterior in the time-honored manner, and had progressed from your hand alone to the use of an implement. Noting your smile and vacant expression, I further deduced that the miscreant was not some urchin boy, but rather an adult female, likely one personally known to you. While neither you nor your wife is averse to the occasional conjugal spanking..."

"Really, Holmes!"

"Hush, Watson. I was saying, you would not have employed the birch, let alone so vigorously, upon the person of your wife. The logical conclusion was that your new maid had committed some transgression, which you felt compelled to correct. Since the birch is effective only on bare flesh, you must have seen her displayed in a shameful but provocative manner. Hence, you stared at the back of my statue of Venus, dreamily contemplating the earlier sight. You looked next at my pillows and at the fireplace, as if wondering whether your maid was sitting uncomfortably, or perhaps even eating off the mantle while standing up. You glanced back at the Venus, a substitute for the actual naked posterior you wished to see a second time. You sighed, and looked away. Your eyes chanced to light upon your medical bag, and a diabolical plan was hatched. As a doctor, you could pretend solicitously to examine the wounds you earlier inflicted. Cold cream would allow you further to touch and even rub the woman's flesh, while assuring both yourself and her that you were motivated solely by concern for her well-being. Asking your wife for her cold cream was out of the question, but you heard Mrs. Hudson downstairs, and a look of triumph appeared on your face. You had conceived the plan to borrow hers. Friend, it does not require the deductive powers I possess to know what would follow these ministrations to the naked bottom of your maid. Go directly to your wife tonight, leave the poor maid alone, and do not violate the sanctity of the marriage bed!"

Crestfallen, I could only nod.

"Don't look so glum, Watson," said Holmes. "Let's get you to your wife, straightaway. With your permission, I shall keep you company in the coach. We shall stop briefly at the apothecary's for a jar of cold cream and a sheepskin."

"But, Holmes! You said..."

"My dear Watson, I am amazed at your simplicity. The solution could not be more elementary. For while you, my friend, have a prior commitment, I am a bachelor!"