Frimmell: Science doesn't take orders, Wally.
Baltzer: Just remember, you can't fill up an empty shot glass with talk.
Shield: A watched pot, Mr. Frimmell, never boils.
Shield: Necessity might be the mother of mechanical invention but she's not even remotely related to chemicals.
Rico: That's a pretty big can of peas.
Ness: Let's try and make it smaller.
Baltzer: You're getting better, Lorna.
Lorna: Not really. It's just that you're looking more and listening less.
Ness: Is there anything you can remember that can help us?
Landlady: Plenty, mister...but not about him!
Baltzer: Frank, you don't understand...
Nitti: You bet I don't understand..and when I don't understand..I get mad! Understand?
Baltzer: Good food and good booze. There's nothing like it.
Freddie: Except a good poker game.
Baltzer: (to Lorna) Baby whadda you want?...I'm in the middle of a raise!
Shield: (about his marriage proposal) I don't expect an answer right away. I'd rather you thought about it until I become a millionaire. It's much easier to answer the proposal of a millionaire.
Lorna: Sure. How long do you think it will take...50 years?
Shield: No...a few weeks.
Baltzer: If you weren't so greedy, Shield, you'd be alive tomorrow morning.
Shield: I intend to be, Wally.
Frimmell: You may intend to be..but trust me..you won't be.
Shield: (to Baltzer) Somebody that tried to kill me has to prove himself before I trust him again.
Shield: You're not the only one who could use killing, Wally.
Shield: Run, Max, run! You got two good legs, use 'em!
Ness: (looking for Baltzer) You spoken to him on the phone?
Lorna: It's been like the day after the chickens were killed...not a peep.
Nitti: (slugs Baltzer) If there's any hitiin' around here I'll do it!
Ness: (regarding Shield) We've got to find him so we can tie that noose around his neck and make him yell guilty.
Shield: How could I have murdered anyone?
Ness: If you've forgotten I'm sure the D.A. will refresh your memory.
Baltzer: Nobody has any booze, Frank.
Nitti: Is that supposed to make me feel better?..cause it don't make me feel better!
Nitti: (after Baltzer has been dragged away) I like a boy who looks after my interests. I like such a boy.
Shield: I didn't do so bad myself, Frank. Wally split a million bucks with me to break up our partnership and now I'll get Wally's share too.
Shield: They'll go easy on me, won't they, Mr. Ness?
Ness: Three murders in two weeks? They'll go easy with you, alright...they'll put a cushion on the electric chair.
Robert Stack wrote in his biography Straight Shooting [page 259 of the paperback edition] that Joseph Wiseman was a fine actor, but trained to work on the New York stage with props; he was not accustomed to real Hollywood sets. In a 1960 Untouchables episode, he was supposed to take an axe and smash up a brewery. He hit a real pipe, the axe ricocheted off the metal, and cut through his Achilles tendon. "I never felt so sorry for anyone in my life," Robert commented. They wrote a part for Joseph as a crippled, renegade chemist a few weeks later in The Antidote which Robert noted "was one of our half-dozen top shows."