First-year students at a Medical School were receiving their
first anatomy class with a real dead human body. They all gathered
around the surgery table with the body covered with a white
sheet.
The professor started the class by telling them, "In medicine, it
is necessary to have 2 important qualities as a doctor. The first
is that you are not disgusted by anything involving the human
body." For an example, the professor pulled back the sheet, stuck
his finger in the butt of the corpse, withdrew it and stuck it in
his mouth. "Go ahead and do the same thing," he told his
students.
The students freaked out, hesitated for several minutes, but
eventually took turns sticking a finger in the butt of the dead
body and sucking on it.
When everyone finished, the Professor looked at them calmly and
told them, "The second most important quality is observation. I
stuck in my middle finger and sucked on my index finger. Now learn
to pay attention...."