outlined, this inability to observe it is precisely what one should expect. It is not possible to analyze the total content of consciousness into any definite number of "states." The total state of consciousness at any given moment depends upon the condition and character of a system of physical activities, and its few distinguishable elements are related to some rather than to other elements of that system. But no portion of the system could be what it is if the other portions were not just what they are, and in the succession of the clearer states of consciousness we see not merely the effect of the one clear state upon the next clear state, but the effect of one whole system upon the next whole system; and often the active factor in determining the character of the next clear state is not what was clearest in the preceding, but one of those which were dimly existent in the margin, or even one of those that were subconscious. To determine the true properties of any state it would be necessary to isolate it by breaking up this co-ordination, and that, as I shall show later, we can to some extent do.
Before taking up these more complex forms of disorganization, or, better, disordination, I must make plain the meaning of the word subconscious, which I have had occasion once or twice to use.
I am sitting in a chair and reading an interesting story; the clock strikes and I do not hear it. Why? There are only four possible theories. We must suppose that the air vibrations strike the ear drum and are propagated through the ear bones and lymph to the auditory nerve. Then either (1) the physical process is blocked at some point between the terminal filaments of the auditory nerve in the inner ear and its origin in the cortex; or (2) the irritation reaches the cortex, but fails to awaken any cortical process; or (3) it awakens a cortical process which is unaccompanied by any mental state; or (4) it awakens both a cortical process and a mental state. For the first of these alternatives there is no evidence. On the contrary, since I hear the clock strike if I am expecting it, and since all theories require us to regard expectation as dependent upon cortical processes, if any mental phenomena are, we must look to the cortex for the explanation and not to the peripheral machinery. The second alternative is conceivable, but there is no direct evidence for it and there is some against it. It is frequently possible, for example, to awaken by hypnotic suggestion a memory of the event which was not consciously experienced, and, as memory depends upon the traces left by earlier experiences in the cortex, it would seem to follow that there must have been a cortical disturbance. The third alternative is more probable. There is reason for believing that any cortical process must attain a certain degree of intensity before its mental concomitant comes into being at all, and per-
