1. In a portable kit for inclining a conventional bed for use by a sleeper requiring therapeutic treatment, said bed including a head end, a foot end, plural legs at each end for supporting the bed on a floor, a mattress support and a mattress resting on the mattress support, the combination comprising:
(a) bed elevating means adapted to be inserted under one end of the bed and operable to raise said end to a selected height to incline the bed longitudinally and
(b) mattress retaining means comprising at least one elongated, generally rectilinear member adapted to be inserted between the mattress and the mattress support and to extend longitudinally from the head end to the foot end of the bed, said retaining means being operable to secure the mattress against displacement relative to the mattress support when the bed is inclined,
(c) each said elongated member of said mattress retaining means having longitudinally spaced bed engaging means, one said bed engaging means comprising an offset extending generally perpendicularly from the member in the direction of the mattress support and being engageable therewith, and one said bed engaging means comprising an offset extending generally perpendicularly from the member in the direction of the mattress and being engageable therewith.