In the novel After the Funeral, Dr Proctor was the doctor in the village of Lytchett St Mary. Susan Banks summoned him when Miss Gilchrist felt ill in the middle of the night. He then called an ambulance to take her to the hospital. Certain that Gilchrist must have eaten something wrong, he returned to her cottage the next day. It must be something Miss Gilchrist had eaten which Susan did not. When Susan recalled the wedding cake, they searched the house and found some crumbs in a discarded box. Analysis of them later showed that they contained traces of arsenic.
Dr Proctor does not appear in the 2006 ITV film adaptation of the book. After Miss Gilchrist had been wared, it was Inspector Morton, Mr Entwhistle and Poirot who went to the cottage to interview Susanna (renamed from Susan in this adaptation). It was Poirot who discovered the wedding cake and explained its significance.