A man walks into a Doctors office and puts a note on the
table in front of the Doctor.

The note says : " I can't talk, help me ! "

The Doctor thinks for a while and says to the man : " Put
your penis on the table here. "

The man thinks this is a bit weird but does as he says.
The Doctor takes a rubber mallet and hits his penis with it
as hard as
he can.

The man cries in great agony:
'AAAAAAAAAAAAAAAAAAAAA.....'
and the Doctor says : " Good, come again tomorrow and
we'll learn B ! "