Gabrielle asks Robert his opinion about spatially tuned memory trace cells, to which Robert asks jokingly if she thinks that he's Andrew Fielding Huxley. Sir Andrew Huxley won the Nobel Prize for Medicine in 1963 for discovering how nerve impulses propagate.
The hansom cab driver is reading a newspaper with the headline Six Years Later: San Marcos a Success. This refers to the American invasion of San Marcos at the end of Season 5.