There was a cupboard on each side of the mantelpiece, and it was in these two cupboards that the dentist kept his professional library.
His books did not form a very valuable collection, but he kept the cupboards constantly locked nevertheless.
He took the key from his waistcoat-pocket, opened one of the cupboards, and selected a book from a row of dingy-looking volumes.

He carried the book to the room above, where he seated himself under the gas, and opened the volume at a place in which there was a scrap of paper, evidently left there as a mark.

The book was a volume of the _Lancet_, and in this book he read with close attention until the Bloomsbury clocks struck three..