Here's a Funny

First-year students at 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 not be 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 his finger 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 had finished, the Professor looked at them 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.