The quirky Broadway producer was as well known for his weird method of casting parts for his productions as he was for the near-certain failure of every show he staged. Perhaps his most kooky method of selecting cast members was the "positive cookie" routine.
After weeding out those with less talent, he would invite each of the call backs, one at a time, into his office, and place before them a plate containing two oatmeal cookies. Under one cookie, hidden by the goodie, was the word "positive." Under the other, "negative." Those who chose "positive" were awarded acting parts. Those who selected "negative" were in the chorus. Before selecting the cookie, which they had to eat, each would-be performer was blindfolded. Only after eating the cookie was the blindfold removed revealing which cookie had been selected. [There were rumors that the producer sometimes moved the remaining cookie to the spot vacated by the one eaten, but that was only a rumor.]
On this occasion, the young lady called into his office really wanted to sing, not act. She didn't feel quite ready for a speaking role. But the producer insisted that she follow the rules. If she chose the positive cookie, she would have to take an acting role.
She sat, he blindfolded her, then spun the plate around several time. [One thing more before the punch line. The "negative" cookie was always laced with a quick acting cure for constipation. The "positive" cookie was just a normal oatmeal cookie.]
The aspiring singer felt the plate, her hands running over each of the cookies. At last, she grabbed them both, chewed and swallowed them quickly.
Aghast, since no one had ever done that, the producer removed her blindfold and pondered what to do. Then it came to him. He responded, singing an abbreviated version of the opening line of a 40s pop tune:
"YOU'VE GOT TO ACT-SINCE-YOU-ATE THE POSITIVE. ELIMINATE THE NEGATIVE,... DON'T MESS..." he ended, pointing to the nearest bathroom door.