SPIRAL

Starting from 1, fill in the grid clockwise with four-letter words. The last letter of each word becomes the first letter of the next to reveal the seven-letter key word in the shaded boxes. 1. Lass 2. Heavy metal 3. Twofold 4. Bereavement 5. Wound mark 6. Moneyed 7. Snake's sound 8. Cult Keyword clue: A surgical knife 9. Mountain lake 10. Organ of smell 11. Simple 12. High-pitched bark 13. Treaty 14. Therefore 15. Slight quarrel 16. Small duck