But the old collie made no advances. He bared his teeth, lifting his lips till the gums showed, and stood stockstill with fixed eyes and heaving sides. The doctor moved a little farther back, watching intently the smallest movement, and it was just then he divined suddenly from the cat’s behaviour and attitude that it was not only a single companion it had ushered into the room, but several . It kept crossing over from one to the other, looking up at each in turn. It sought to win over the dog to friendliness with them all. The original Intruder had come back with reinforcements. And at the same time he further realised that the Intruder was something more than a blindly acting force, impersonal though destructive. It was a Personality, and moreover a great personality. And it was accompanied for the purposes of assistance by a host of other personalities, minor in degree, but similar in kind.