Thirdly, there is the theory that the subconscious mind is composed entirely of dissociated or split-off ideas--ideas which have been dissociated or split off from the main stream of consciousness, much as a few freight cars might be shunted on to a side track by the switch-engine. This hypothesis is very similar to another theory, which contends that the subconsciousness consists of dissociated experiences--mental happenings which have been forgotten or passed beyond voluntary recall. For these mental states, or rather trains of thought, Prince has suggested the term "co-conscious," because they are conscious processes in operation at the same time as the normal consciousness. This theory is doubtless far nearer an adequate explanation of the facts than that which contends that the subconscious is merely a portion of the field of consciousness which happens to lie outside the field of _attention_, because _that_ is a theory certainly inadequate to cover the facts. This last hypothesis is one which seems to be favoured by Coriat and others, but it is certainly limited in its application. Now let us see if we cannot obtain a clearer grasp of the facts, in view of the above discussion as to the nature of the subconscious mind. We may sum-up the facts as follows:-- As the result, either of some sudden shock, or by reason of certain subjective psychological practices carried to an extreme, we have a splitting of the mind into two or more separate streams, which function separately and independently, and generally with no memory connection between the two, so that each is ignorant of what the other stream, or self, is doing. This is already an abnormal condition, a pathological state, and its severity depends upon the degree of cleavage between the streams of thought. If this be deep and lasting, we have a well-marked case of hysteria, or other disorders to be noted immediately; if, on the other hand, the cleavage be slight, we have merely absent-mindedness, wandering of the mind, and many lesser symptoms which indicate this tendency to dissociation, and which should be checked at all costs in their inception, since they are symptomatic of the tendency to disintegration of the mind, and which, if unchecked, would lead to grave disturbances later on. It is because of this fact that too much automatic writing, crystal-gazing, meditation, attendance at spiritistic circles, etc., is harmful; they one and all induce a passive state of the mind which favours dissociation and disintegration. Many of the insanities start in this fashion; and all such practices, instead of being encouraged, should be discouraged; and all experienced and intelligent students of psychical research warn those who "dabble" in the subject against the repeated and promiscuous indulgence in such practices--because of the dangerous, even disastrous, effects upon the mind, in many instances.