During a lecture for medical students, the professor listed the two best qualities of a doctor to be:
- the ability to conquer revulsion; and
- the need for keen powers of observation.
He illustrated this by stirring a messy substance with his finger and then licking his finger clean. Then he called a student to the front and made him do the same.
Afterward the professor remarked,
“You conquered your revulsion, but your powers of observation are not very good. I stirred with my forefinger, but I licked my middle finger.”