The receipt by the testator of a part of an entire thing specifically bequeathed shall operate as an ademption of the legacy to the extent of the sum so received,
Illustration
A bequeaths to B "the debt due to me by C'. The debt amounts to 10,000 rupees. C pays to A 5,000 rupees the one-half of the debt. The legacy is revoked by ademption, so far as regards the 5,000 rupees received by A.