When one is in one’s seventies, as I am, one begins to fear the horror of dementia and to carry out anxious checks on one’s memory to see if the brain is still working. The results in my case are not very encouraging. For example, it took me several days to remember that the film star who canoodled with Leonardo DiCaprio in the stern of the Titanic was called Kate Winslet, although I am an admirer of hers and even once met her.