• The Spirits' Book

    • Book Two - The Spirit World

      • Chapter XI - The Three Kingdoms

        • Metempsychosis

612. Can a spirit which has animated a human body be incarnated in an animal?

"No; for such an incarnation would be a retrogradation; and a spirit never retrogrades. The river does not flow back to is source." (See Q118)

Source: Kardecpedia