Another scoffer was Democritus of Abdera, who was so firmly convinced of the non-existence of ghosts that he took up his abode in a tomb and lived there night and day for a long time. Classical ghosts seem to have affected black rather than white as their favourite colour. Among the features of the gruesome entertainments with which Domitian loved to terrify his Senators were handsome boys, who appeared naked with their bodies painted black, like ghosts, and performed a wild dance.[29] On the following day one of them was generally sent as a present to each Senator. Some boys in the neighbourhood wished to shake Democritus's unbelief, so they dressed themselves in black with masks like skulls upon their heads and danced round the tomb where he lived. But, to their annoyance, he only put his head out and told them to go away and stop playing the fool. The Greek and Roman stories hardly come up to the standards required by the Society for Psychical Research. They are purely popular, and the ghost is regarded as the deceased person, permitted or condemned by the powers of the lower world to hold communication with survivors on earth. Naturally, they were never submitted to critical inquiry, and there is no foreshadowing of any of the modern theories, that the phenomenon, if caused by the deceased, is not necessarily the deceased, though it may be an indication that "some kind of force is being exercised after death which is in some way connected with a person previously known on earth," or that the apparitions may be purely local, or due entirely to subjective hallucination on the part of the person beholding them. Strangely enough, we rarely find any of those interesting cases, everywhere so well attested, of people appearing just about the time of their death to friends or relatives to whom they are particularly attached, or with whom they have made a compact that they will appear, should they die first, if it is possible. The classical instance of this is the well-known story of Lord Brougham who, while taking a warm bath in Sweden, saw a school friend whom he had not met for many years, but with whom he had long ago "committed the folly of drawing up an agreement written with our blood, to the effect that whichever of us died first should appear to the other, and thus solve any doubts we had entertained of the life after death." There are, however, a number of stories of the passing of souls, which are curiously like some of those collected by the Society for Psychical Research, in the Fourth Book of Gregory the Great's Dialogues.