The government and religious institutions have a great power over the culture of a place. This is because they are often the ones that determine a place culture, although sometimes, cultures also emerge from the bottom-up, and reach government and religious institutions in this manner.
The answer is C Calhoun claimed that the slave system was better than the “wage slavery” in the north. There is more on John C. Calhoun at www.historynet.com
He tells John that he would like the "experiment" (of John living in London society) to continue. In other words, he is interested in continuing to experiment with John's life at John's expense.