Sleep, My Love is Douglas Sirk's crack at Gaslight. Dabbling in drugs and Mesmerism, Don Ameche rigs up psychotic "episodes" starring his wife, Claudette Colbert, so he can inherit her money. Befriended by Robert Cummings during one of these arranged "fugue" states, she unwittingly enlists an ally whose affections, and suspicions, grow. (The film takes on inadvertent Charlie Chan overtones when Cummings goes sleuthing with his blood-brother Keye Luke, who often played the Honolulu detective's eldest offspring.)
Unlike Cukor's claustrophobic Gaslight, with Ingrid Bergman and Charles Boyer, Sleep, My Love is less psychologically nuanced and more plot-driven. It benefits from Hazel Brooks, delivering an icily stylized vamp turn as The Other Woman; she appeared in one other noir, Body and Soul, during her disappointing brief career. George Couloris (the guardian in Citizen Kane) adds color as a confederate of Ameche's, while Raymond Burr is wasted as a minion of the law.
That leaves the three principals as well as some problems. The amicable Ameche can't summon up the cold, controlling menace that Boyer spread through Gaslight; his adversary, the equally amicable Cummings, succumbs to terminal blandness. Colbert is more problematic. Unlike the languorous, instinctive Bergman, she made her name in part due to her quick wits; you can't buy her as a submissive wifey who hasn't cottoned on to her husband's philandering -- at the very least -- without having it spelled out to her by Cummings, whose acumen seems as low-wattage as his star power. (On the other hand, she was to find herself in a similar pickle the next year in The Secret Fury.) Sirk's direction here, as in Lured, lacks the distinctiveness he showed in his other noir, Shockproof, and was to develop lushly in the haut-fifties melodramas like Written on the Wind for which he is justly renowned.
