The healing hand spell supplied additional healing to a creature that had already been healed within the previous 24 hours. If the intended recipient was not present, then the caster of healing hand could work with the caster of the previous healing spell, who concentrated on and visualized the recipient. Any on these three people could be the same if required.
A full 48 hours was required before another casting of healing hand could be applied.
The spell required a scrap of skin and a sliver of bone, of any type, size, age, and species.