Three nurses who worked at the same clinic decided one morning that they were going to play a few harmless jokes on the doctor.

He was always serious, always rushing around, and rarely smiled, so they thought it would be funny to loosen him up a little.

Later that day, during their break, the three nurses met in the staff room and started laughing about what they had done.

The first nurse grinned and said, “I put cotton inside his stethoscope. Every time he tried to listen to a patient’s heartbeat, he couldn’t hear a thing.”

The other two laughed.

The second nurse leaned forward proudly and said, “That’s nothing. I did something even worse.”

“What did you do?” asked the first nurse.

The second nurse smirked and said, “I poked holes in all his protection.”

There was a moment of silence.

Then the third nurse’s face went completely pale.

The first nurse noticed and asked, “Are you alright?”

But before she could answer, the third nurse fainted.