(a)Where during the period after the 30th September, 1937 and before the 30th January 1948, the equity of redemption in the property subject to the mortgage has devolved either wholly or in part on a person, by or, through a transfer inter vivos either from the original mortgagor or from a person deriving title from or through such mortgagor otherwise than by a transfer inter vivos , then, to the whole or such part, as the case may be -