There was only his word for it, said Gandolph, that he had spoken to Florence of botulism and had warned her against these particular canned herrings. Of course he had never seriously expected those cans to infect Winchurch, but that the fish should be eaten by him was necessary for his strategy. On the night before Winchurch’s death, after dining with his sister at Paraleash House, he had introduced strychnine into the port decanter. He had also, Gandolph suggested, contrived to bring the conversation round to a discussion of food and to fish dishes. From that it would have been a short step to get Winchurch to admit how much he had enjoyed Filets de hareng marinés à la Rosette and to ask Florence to have them served again on the following day. Edward, apparently would have been highly likely to take his doctor’s advice, even when in health, even on such a matter as what he should eat for the fourth course of his dinner, while Edward’s wife did everything her lover, if not her husband, told her to do.

It was no surprise to Frank Fenton to be called out on the following evening to a man whose spasms only he would recognize as symptomatic of having swallowed strychnine. The arrival of Dr Waterfield was an unlooked-for circumstance. Once Winchurch’s symptoms had been defined as arising from strychnine poisoning there was nothing left for Fenton to do but shift the blame on to his mistress. Gandolph suggested that Fenton attributed the source of the strychnine to Anstruther’s chemist’s shop out of revenge on Anstruther for calling in Waterfield and thus frustrating his hopes.

And what grounds had Gandolph for believing all this? Certain entries in Ada Hurst’s diary. Wexford read them slowly and carefully.

For 27 February 1900, she had written, filling the entire small space: Very cold. Leg painful again today. FW sent round the carriage and had John drive me to Pomfret. Compton says rats in the cellars and the old stables. Dined at home with F who says rats carry leptospiral jaundice, must be got rid of. 28 February: Drove in FW’s carriage to call on old Mrs Paget. FW still here, having tea with F when I returned. I hope there is no harm in it. Dare I warn F? 29 February: F destroyed twenty rats with strychnine from his dispensary. What a relief! 1 March: Poor old Mrs Paget passed away in the night. A merciful release. Compton complained about the rats again. Warmer this evening and raining. There was no entry for 2 March. 3 March: Annie gave notice, she is getting married. Shall be sorry to lose her. Would not go out in carriage for fear of leaving FW too much alone with F. To bed early as leg most painful. 4 March: My birthday. 26 today and an old maid now, I think. FW drove over, brought me beautiful Indian shawl. She is always kind. Invited F and me to dinner tomorrow. There was no entry for 5 March, and the last entry for nine months was the one for 6 March: Dined last night at Paraleash House, six guests besides ourselves and the Ws. F left cigar case in the dining room, went back after seeing me home. I hope and pray there is no harm.