Chapter 32 describes how Pip, having some time to kill before meeting Estella when she arrives in London, is given a tour of Newgate prison by Wemmick. This Chapter is interesting for a number of reasons, but chiefly because it shows Wemmick carrying out his official business as Jaggers' agent. He is clearly professionally detached from his business, and the use of the gardening imagery that runs through the passage underlines this. It is highly significant that after this tour, Pip is troubled by what happened in the marshes - his criminal assocations through Wemmick recall us to his former criminal associations and his own crime at the beginning of the story.
The vegetation imagery is a key feature of this passage:
It struck me that Wemmick walked among his plants. This was first put into my head by his seing a shoot that had come up in the night, and saying, "What, Captain Tom? Are you there? Ah, indeed?"
Thus reference is made to a new prisoner who has just been brought into prison, providing Wemmick and Jaggers with a new case. This is continued in the passage when Wemmick says farewell to a prisoner who has lost his case and now is to be hung:
With that he looked back, and nodded at his dead plant, and then cast his eyes about him in walking out of the yard, as if he were considering what other pot would go best in its place.
This prisoner, having lost his case, is now a "dead plant" to Wemmick - nothing more can be got out of it. Such imagery highlights the self-serving nature of the business of Wemmick and Jaggers - they look for "plants" they can "nurture" and "grow" to get money out of. When the prisoners have lost their case, they "die" as plants in the sight of Wemmick and Jaggers, once all "portable property" has been extracted from them.