Can there be a biological mutation in the cells of the brain? If there are a few people, say half a dozen people in the world, who have really brought about a biological mutation, a great radical change, it would affect the stream of consciousness. If each one felt the immense responsibility of this and were no longer swimming in the stream, it would be marvellous. It would certainly affect the whole stream. One would affect it somewhat, but if there were fifty or a hundred people, naturally it would be an immense thing.