Cissie cries, "She mustn't!" and puts her right hand to her throat. In the next shot, she's covering her throat with her left hand.
In the intro, Mr. Hitchcock says that he just added ten ccs of sugar to his recipe. CCs, or cubic centimeters, are a measure of liquid or gaseous volumes, not of weight. He should have said grams of sugar, which would be a solid.
Mr. Brenner states that Joanna Enright tried to kill him with an ax. She was wielding a cleaver, not an ax.