One afternoon, as Moshe Levy returns home, he slips on the pavement and hurts his leg. He phones Dr. Jacobs immediately.
"Oy veh, doctor," says Moshe, "have I hurt my leg! What should I do?"
"So tell me already," asks Dr. Jacobs, "what exactly are your symptoms?"
Moshe explains his symptoms to Dr. Jacobs, such as where the leg pain is and how swollen it is. Then, after a short period of silence, Dr. Jacobs says, "You should soak your leg in hot water."
Moshe thanks the doctor, runs a hot bath and spends the next 30 minutes keeping his bad leg under the hot water. But the leg swells up even more, causing Moshe to moan out loud.
Moshe's housekeeper hears his moaning, knocks on the bathroom door, and asks him if he's alright. Moshe tells her what Dr. Jacobs had told him to do.
"But that's not right, Mr. Levy," says his housekeeper. "Everyone knows that you should bathe swollen limbs in cold water, not hot. That why it's not getting better."
Moshe thanks her, lets the hot water out the bath and refills it with cold water. Bathing his leg in the cold water helps a lot and the swelling quickly subsides.
After drying himself and getting dressed, Moshe leaves the bathroom and phones Dr. Jacobs.
"What kind of doctor are you? You tell me to soak my injured leg in hot water, and it swells up even more. But then my housekeeper tells me I should have been soaking it in cold, not hot water. And when I do this, my leg gets better."
"I don't understand it," says Dr. Jacobs, "my housekeeper distinctly told me you should soak a swollen leg in hot water!"