Clayton Smith on Iris Acht... Translated,“acht” would have a meaning akin to the authoritative command, “Pay attention!” Given Nabokov’s knowledge of German and penchant for linguistic games, there can be little doubt that he is telling astute readers in no uncertain terms to look at this passage, and specifically Iris Acht, very carefully."
Please don't forget the original Iris Acht - - an unfortunate actress who dies young in a wild novel, the victim of a gray villain.