Residents...

First year students of MBBS (Medicine) were attending their first anatomy class.
They are gathered around the Surgery table with a real dead dog lying on it.

The Professor started class by telling two important qualities as a Doctor.The First is that to never be disgusted about any part of the body,
As he inserted his finger in dog's ass tasted it in his own mouth. Then he said them to do the

 same.

The students hesitated for several minutes but eventually everyone inserted their fingers in dog's ass & then tasted it.

When everyone finished, the Professor looked at them and said:
The second most important quality is Observation, I inserted my Middle finger but tasted the Index finger.

Now... learn to pay attention.