Dentist in the Chair1960

[Sam Field is masquerading as a fictitious student John Sam. The instructor is not impressed with his efforts in class]

Dental Instructor:
Would you like to hear the substance of my report to the Dean? "Lecturer's Report, 18th instant. Dear Sir. The student John Sam appears to me to be the epitome of all that is retrogressive and reprehensible. He is vacuous, indolent, disputatious and completely illiterate. He is, in your own splendid phrase, Sir, 'a perfect coagulation of the plasma'."

Sam Field:
[shaking the instructor's hand] And I thought you didn't like me. What does that mean, Sir, 'a coagulation of the plasma'?

Dental Instructor:
A clot.