Brain Store

A man went to a brain store to get some brain for dinner.
He sees a sign remarking on the quality of professional brain
offered at this particular brain store. So he asks the butcher:
"How much for Engineer brain?"
"3 dollars an ounce."
"How much for doctor brain?"
"5 dollars an ounce."
"How much for lawyer brain?"
"90 dollars an ounce."
"Why is lawyer brain so much more?"
"Do you know how many lawyers you need to kill to
get one ounce of brain?"