KISS OF DEATH   Moments after a high tea is interrupted by a fire in the servants' hall, art collector Daniel McCourt is found sprawled on the floor of his study under a bundle of mistletoe, his throat slit by the bloody sword lying next to his body. Could the killer be a disgruntled lover, sending a message by murdering McCourt under the mistletoe? Could it be one of his fellow collectors, pointedly using one of McCourt's own acquisitions to kill him?   Inspector Witherspoon is determined to solve the case--preferably before Christmas Eve--but of course he will need some assistance from the always sharp-witted Mrs. Jeffries, who has her own theories on why McCourt had to die by the sword...   A Mrs. Jeffries Mystery