Section 27. If the testator, by making a specific devise or bequest, has virtually exempted a devisee or legatee from liability to contribute with the others for the payment of the debts, or if by any other provisions in his will he has prescribed or required an appropriation of his estate different from that prescribed in the preceding section, his property shall be appropriated and applied in conformity with his will, so far as such appropriation and application can be made without affecting the liability of his whole estate for the payment of his debts.