"If the tenant of New Inn was John, then Jeffrey must be elsewhere, since his concealment at the inn was clearly impossible. But he could not have been far away, for he had to be producible at short notice whenever the death of Mrs. Wilson should make the production of his body necessary. But if he was producible, his person must have been in the possession or control of John. He could not have been at large, for that would have involved the danger of his being seen and recognized. He could not have been in any institution or place where he would be in contact with strangers. Then he must be in some sort of confinement. But it is difficult to keep an adult in confinement in an ordinary house. Such a proceeding would involve great risk of discovery and the use of violence which would leave traces on the body, to be observed and commented on at the inquest. What alternative method could be suggested?
"The most obvious method is that of keeping the prisoner in such a state of debility as would confine him to his bed. But such debility could be produced by only starvation, unsuitable food, or chronic poisoning. Of these alternatives, poisoning is much more exact, more calculable in its effect and more under control. The probabilities, then, were in favor of chronic poisoning.
"Having reached this stage, I recalled a singular case which Jervis had mentioned to me and which seemed to illustrate this method. On our return home I asked him for further particulars,