The fact that they were empty and not thrown away suggests that they were administered by Mary Ann Cotton and as directed by the physicians. However a point to note in Mary Ann Cotton’s trial in March of 1873, was the confusion raised concerning the medications actually administered by Kilburn and Chalmers. Both practitioners gave very patchy and at times contradictory evidence concerning those medications actually prescribed. This matter alluded to the medication's shelf within Kilburn and Chalmers surgery and the proximity of the poison's shelf to the normal dispensed prescriptions and medications. As we remember in Dr. Kilburn’s statement he told the Durham Assizes, that the location of the arsenic bottles in his surgery was in a secure place on a specific shelf, well away from the everyday prescriptions and normal medications to be issued. His assistant Dr. Chalmers totally contradicted that statement by saying that he thought the location of the arsenic bottles was on a different shelf from that mentioned by Dr. Kilburn and may have been closer to the prescription and normal medications shelf, but could not be more specific. This statement is an important piece of evidence and in today’s modernity, a trial Judge would almost certainly instruct the jury to remember that point when deliberating their verdict. He would also remind the jury of West Auckland Police Sergeant Hutchinson’s comments concerning the mysterious disappearance of the medicine bottles, prescribed by Kilburn and Chalmers, when he and the other police officers searched Mary Ann’s house in July of 1872. Sgt Hutchinson, said that “when he conducted the search of Mary Ann Cottons house, Dr. Kilburn was present and I think that he took some of the empty medicine bottles away.” Dr. Kilburn said “I removed nothing from the house except what was sent to the forensic examiner Dr. Scattergood, I took no bottles away, which had any medicine in them.”
Did Dr. Kilburn observe those medicine bottles during that search, or did he have cause to remove them because, the label on the bottle described a substance which was definitely not for medicinal purposes, or was he doubting that the medications he and Chalmers prescribed may have been excessive? It is perhaps appropriate to end this dilemma by also “muddying the waters” by stating that no medication bottles were produced into any evidence as having been analysed by Dr. Scattergood the forensic examiner, although Dr. Kilburn insisted he sent them to Leeds! As to where the empty medicine bottles disappeared to, is a matter for you to guess as Dr. Kilburn never mentioned the subject again, and steadfastly maintained for the rest of his life that he took no bottles from Mary Ann Cotton’s house! Part of the prosecution's case against Mary Ann Cotton was that she possessed arsenic and had the knowledge and motive to use it. As we remember Mary Ann did use the arsenic in a mixture often called soft-soap. Like others across the north-east she used the mixture to clean her house and to kill bed bugs and lice.