Section 10. Gifts whenever made where donor not entirely excluded

10. Gifts whenever made where donor not entirely excluded.—Property taken under any gift, whenever made, shall be deemed to pass on the donor's death to the extent that bona fide possession and enjoyment of it was not immediately assumed by the donor and thenceforward retained to the entire exclusion of the donor or of any benefit to him by contract or otherwise: Provided that the property shall not be deemed to pass by reason only that it was, not, as from the date of the gift, exclusively retained as aforesaid, if, by means of the surrender of the reserved benefit or otherwise, it is subsequently enjoyed to the entire exclusion of the donor or of any benefit to him for at least two years before the death.