Students at a well known Med School were receiving their first anatomy class with a real cadaver. They were all gathered around the lab table with the body covered with a white sheet.
The professor started the class by telling them, "In medicine, it is necessary to have two important qualities as a doctor:Â The first is that you absolutely must not allow anything to disgust you."
With that, the Professor uncovered the sheet, sunk his finger in the corpse’s butt, withdrew it, and then stuck his finger in his mouth and sucked it.
"Go ahead and do the same thing." he told his students.
The students freaked out, hesitated and subsequently taking turns, sunk their finger in the butt of the dead body and queasily stuck it in their mouths and sucked on their finger.
When everyone finished, the Professor looked at them and said, "The second important quality is observation. I inserted my middle finger and then sucked on my index finger. Pay attention people!