Joke on the doctor

Four nurses all decided to play a joke on the doctor they worked for,
whom they all felt was an arrogant jerk. Later in the day, they all
got together on break and discussed what they had done to the doctor.

The first nurse said, "I stuffed cotton in his stethoscope so he couldn't hear."

The second nurse said, "I let the mercury out of his thermometers and
painted them all to read 106 degrees."

The third nurse said, "Well, I did worse than that. I poked holes in
all of the condoms that he keeps in his desk drawer."

The fourth nurse fainted.