Defining a CAT

Dr. Piloo Rustomjee was Senior House Officer in Surgery working under Dr.P.R. Anthonis. At any party Piloo would pull out a small notebook from his trouser pocket. He would scrutinize it for a few minutes and replace it. He will then have a fund of jokes to relate  for the next one hour. He gave a definition of a CAT as ‘The only type of ball-bearing rat-trap available in the market’. We were not quite sure whether he was referring to the four-legged or the two-legged variety.