Here we have an automatic message of traceable origin; a message implanted in the hypnotic stratum of the subject's self, and cropping up--like a fault--in the waking stratum,--externalised in automatic movements which the waking self could neither predict nor guide. Yet once more. In the discussion which will follow we shall have various instances of the transformation (as I shall regard it) of psychical shock into definite muscular energy of apparently a quite alien kind. Such transformations of so-called psychical into physical force--of will into motion--do of course perpetually occur within us. For example, I take a child to a circus; he sits by me holding my hand; there is a discharge of musketry and his grip tightens. Now in this case we should call the child's tightened grip automatic. But suppose that, instead of merely holding my hand, he is trying with all his might to squeeze the dynamometer, and that the sudden excitation enables him to squeeze it harder--are we then to describe that extra squeeze as automatic? or as voluntary? However phrased, it is the fact (as amply established by M. Féré and others[163]) that excitations of almost any kind--whether sudden and startling or agreeable and prolonged--do tend to increase the subject's dynamometrical power. In the first place, and this is in itself an important fact, the average of squeezing-power is found to be greater among educated students than among robust labouring men, thus showing that it is not so much developed muscle as active brain which renders possible a sudden concentration of muscular force. But more than this; M. Féré finds that with himself and his friends the mere listening to an interesting lecture, or the mere stress of thought in solitude, or still more the act of writing or of speech, produces a decided increase of strength in the grip, especially of the right hand. The same effect of dynamogeny is produced with hypnotic subjects, by musical sounds, by coloured light, especially red light, and even by a hallucinatory suggestion of red light. "All our sensations," says M. Féré in conclusion, "are accompanied by a development of potential energy, which passes into a kinetic state, and externalises itself in motor manifestations which even so rough a method as dynamometry is able to observe and record." I would beg the reader to keep these words in mind. We shall presently find that a method apparently even rougher than dynamographic tracings may be able to interpret, with far greater delicacy, the automatic tremors which are coursing to and fro within us. If once we can get a spy into the citadel of our own being, his rudest signalling will tell us more than our subtlest inferences from outside of what is being planned and done within.