An Oldie but a Goodie

This is a very OLD medical joke but since I haven't seen it posted here I will relate it for those who haven't heard it yet.

One day a lecturer was talking to a group of nursing students about urine testing and started explaining about how diabetes Mellitus was orignally named because the urine tasted sweet.

This was announcement was met with derision especially from one young man in the front row.

"come here!" demaded the lecturer. "Watch this!" and with that he dipped his finger in the urine and licked it. "See he said - it IS sweet! I dare you to do the same."

"You're on!" replied the student who proceeded to do the same.

"Ha!" Cried the lecturer "This should be a lesson to you all about the value of observation for although I dipped my forfinger into the urine I licked my middle finger!"

"I know Sir" answered the student "So did I.