The strange thing is that he should have kept the book which had probably been given to him by the prison chaplain.

Still everybody makes mistakes sometimes.

Or it may have had associations for him, and of course he had never seen this stamp upon an unread page, which happened to leap to my eye.
Now I was able to make a shrewd guess at his later career.

After his trouble he had emigrated and began to practise in South Africa.

Somehow his identity had been discovered; his past was dragged up against him, possibly by rivals jealous of his skill; his business went and he found it advisable to retire to the Transvaal before the Annexation, at that time the home of sundry people of broken repute.