Summary. It was Dr Tobias Quill, and he did it for fear of a woman he had never had cause to fear before; here is how the thing stands.

The Reckoning. He had certified deaths in that town for nine years, being the only physician and the only coroner besides, and had certified a good many of them as suited him rather than as they had fallen out. Nan Pringle, who kept every column in the Manor's ledgers and had lately buried her own maid, spent three days at the parish burial register and found what he had spent nine years arranging that nobody should find — a pattern of deaths one man had both attended and signed away. She said as much at dinner, mildly, meaning to ask him about it kindly, as she asked him most things. She was copying the dates out at the table's foot that very evening when he crossed to his open bag on the window-seat, drew off the digitalis he carries for the Colonel's palpitations, and tipped it into her beef tea on his way back. It sat there unwatched from 9:15, when Zane set it down, until she had drunk it through and died in her chair before half past ten, composed, as she generally was. He examined her himself, gave a failing heart, and wrote the certificate before eleven, being himself the only authority the town keeps for doubting him. His hand was not steady that night — he overset a glass weight at a quarter past nine and mistook one campaign sheet for another twice after — which is not the hand of a man untroubled by an argument about the Punjab.

The house looked first at the engagement, as houses will. Aziz might have grudged her the marriage on his employer's behalf, but he held down the corner of the Kabul sheet at the table's head the whole evening, by the word of the Colonel, Cousin R, and Xerxes together, and never went near the table's foot nor the window-seat where the phials stood. Fifi had reason to fear what Nan might say of the twins, but she sat over the mending basket in the linen-room from a quarter to nine until the alarm was raised, with Mrs Gow beside her the entire time, and so was nowhere near the cup. Wat Frew wanted what Nan knew and disliked being refused it, but he quit the map-room at nine, a quarter hour before the beef tea ever came up, and was over the harness in the stable yard till half past ten, by the groom's word and Mrs Gow's both. None of the three was ever alone with that cup, and the doctor was never anywhere else.

The true matter had nothing to do with Xerxes Hartfield or any marriage. It lay in the burial-club page, ruled off in Nan's own hand, with a query set in the margin against Dr Quill's initials. She was the one soul in that house he had never been afraid of — they had grown up together at Dunkeld, and he kept the chair by her fire and called her by her Christian name, which he did for no one else living. But a frightened man's mercy runs only so far as his fear does not reach, and on that particular evening she had, without meaning it, become the one thing he could not bear near him: a person who saw him plainly and meant, kindly, to ask. He did not kill an enemy at that table. He killed the last person left to him who was not one, because she had turned, in an evening, into his coroner. I have laid an information against Dr Tobias Quill for the wilful murder of Nan Pringle, the third this twelvemonth, by my count, and none of them, I think, easier to close than this.

Quill, with a tremulous hand, made a neat little plan
And Nan took her tea as a dutiful Nan
The household still pored o’er the Kabul sheet
While death sat decorously under the seat
The moral, we’re certain, is trust what is said
And promptly forget it when someone is dead