" a changeling in a cradle "
In the fairy tale and folkloric traditions, changelings are magical creatures left in the place of human children who have been snatched away by otherworldly beings. Sometimes the changeling child is not a living being but a "stock" -- an enchanted item, such as a piece of wood, that would eventually wither and die. It is believed that the notion of changeling children served to explain the loss of a child to an unexplained ailment, and to explain physical deformities and disabilities in children. In Madame de Villeneuve's "Beauty and the Beast," Beauty is a changeling child, the daughter of a king and a fairy.
" an evil-smelling little bottle "
The evil-smelling little bottle likely refers to a bottle of smelling salts, a compound of ammonia spirits often used to revive those who have fainted or been knocked unconscious. The smell of the compound irritates the air passage and so brings about a reaction.