Bannerman's prescriptions were made up by a fellow named Barclay, who had been dispenser at Nathaniel's and afterwards set up as a chemist in Sackville Street.

This man was absolutely in my power.

I had discovered him at Nathaniel's in dishonest practices, and I held evidence which would have sent him to gaol.

I held this over him now, and I made him, unknown to Bannerman, increase the doses of aconitine in the medicine until they were sufficient for my experimental purposes.

I will not enter into figures, but suffice it that Bannerman was giving more than ten times what he imagined.
"You know the sequel.