In an exchange program with the University of Texas and Texas A&M's Vet
School the UT students were receiving their first anatomy class, with a real
dead cow. They all gathered around the surgery table with the body covered
with a white sheet.

After welcoming the students, the professor started the class by telling
them, "In vet medicine, it is necessary to have two important qualities as a
doctor:

The first is that you not be disgusted by anything involving the animal
body. For an example", the Professor pulled back the sheet, stuck his finger
in the butt of the dead cow, 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 anal opening of the dead cow and sucking on it.

When everyone 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."