(1)Any disposition made by the deceased in favour of a relative of his shall be treated for the purposes of section 9 as a gift unless.-(a)the disposition was made on the part of the deceased for full consideration in money or money's worth paid to him for his own use or benefit; or(b)the deceased was concerned in a fiduciary capacity imposed on him otherwise than by a disposition made by him and in such a capacity only ; and references to a gift in this Act shall be construed accordingly :Provided that where the disposition was made on the part of the deceased for partial consideration in money or money's worth paid to him for his own use or benefit, the value of the consideration shall be allowed as a deduction from the value of the property for the purpose of estate duty.