occurred; at the time my back was to the factory, and I am quite unable to say how long an interval occurred between the shock of the explosion and my own action in turning round to observe the straight shaft of smoke and solid material high in the air; there was a gap in consciousness, an interval of unknown and seemingly considerable length, caused by the deafening shock of the explosion, although it is probable that my action in turning round was almost or quite instantaneous. It seems to me that the transition from sleeping consciousness to waking consciousness occurs in a similar manner on a smaller scale. Although the view of Foucault that the dream is logically organised after sleep has ended seems, when we examine the evidence in its favour, to be unacceptable, we may still admit that, in some cases at all events, the dream only assumes final shape at the moment when sleeping consciousness is breaking up, that the dream, as we know it, is a final synthetic attempt of sleeping consciousness as it dissolves on the approach of waking consciousness. Sleeping consciousness, we may even imagine as saying to itself in effect: 'Here comes our master, Waking Consciousness, who attaches such mighty importance to reason and logic and so forth. Quick! gather things up, put them in order--any order will do--before he enters to take possession.' That is to say, in other words, that as sleeping consciousness comes nearer to the threshold of waking consciousness it is possible that the need for the same kind of causation or sequence which is manifested in waking consciousness may begin to make itself felt even to sleeping consciousness. Even this assumption seems, however, as regards most dreams, to be extravagant. In any case, and at whatever stage the dream is finally constituted, we are not entitled, it seems to me, to believe that any stage of its constitution falls outside the frontiers of sleep. It is satisfactory to be able to feel justified in reaching this conclusion. For if dreams were chiefly or mainly the product of waking consciousness they would certainly lose a considerable part of their significance and interest.