Drinking House Keeper

Joe was a house keeper who had this habit of drinking from his boss’s liquor bottle and replacing it with water. The boss, James, did suspect him but tolerated it for a while. However, when this became a daily routine, James decided to do something to trap Joe.
Accordingly, James replaced his drink with a French wine which changed color when water was added to it. Joe, not aware of the trap, took a few swigs and added water as usual. The wine changed color from red to milky white. Joe realized he was in for trouble but was determined to get out of it.
James told his wife about Joe’s misdoings and that he would make Joe accept his follies. So he shouted: “Joe? “
Joe answered from the kitchen: “Yes boss?”
James: “Who drank my wine and added water in the bottle?”
There was no answer from the kitchen. The boss repeated the question, still no answer. The angry boss marched to the kitchen and threatened Joe, “What the hell is going on? When I call your name you respond with ‘Yes Boss’ and when I ask you a question, you remain silent. What impertinence?”
Joe said: “It is like this. In the kitchen, you can hear only your name being called. You don’t hear anything else that is said, I swear.”
James: “How is that possible? All right, I will prove you wrong. You stay right here in the hall with Madam, I will go to the kitchen and you ask me a question, OK?” So the boss went to the kitchen.
Joe shouted: “Boss?”
Boss: “Yes Joe?”
Joe: “Who becomes intimate with the maid in Madam’s absence?”
Silence.
Joe again: “Who made the maid pregnant?”
No reply.
Joe, yet again: “And who arranged for her abortion?”
James came running from the kitchen and said: “By George, you are right. When one is in kitchen, one can’t hear anything but one’s name. That’s strange!”