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 favour 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.