In the more pronounced states of suggestibility, the changes which the mind undergoes are many and profound. These changes tend to throw light upon the data belonging to this special field of investigation. Rational activity tends to continue along the lines of the individual's intellectual habits. Perception becomes modifiable even to the degree of producing hallucination and delusions of almost all possible types. Sensibility to minute and weak stimulations is, or can be, increased. Anaesthesia is quite as easily induced, especially in deep sleep. The motor consciousness is let loose, so to speak, and the ordinary control of muscles seems to be exactly inverted. Emotional excitability is apt to be subdued. In a general way, there results a depression or an exaltation of mental activity; but which type of change from the normal will take place cannot be told a priori, - so varied and often contradictory are the phenomena presented. Mental activities are not absolutely suspended (excepting more or less imperfectly in cataleptic sleep). The structural phases of mind remain the same as in normal consciousness.

Thus retaining, reproducing, and recollecting the varied forms of sensory, ideational, and motor contents of hypnoses continue, and offer their special problems for investigation.

It is not an easy matter for the psychologist to analyze the two forms of memory presented under normal and under hypnotic conditions. General mental healthiness is, to both the lay and the trained mind, indicated by the scope and degree of accuracy of the function of remembering. To forget indiscriminately is a sign of a "break-down." Every one is ordinarily expected to remember more or less of the details of his experience. The psychologist must never forget that the standard for evaluating all experiments and reports of isolated cases is necessarily that which can be afforded by what we may call normal memory. The difficulties besetting an application of this standard of memory conditions and memory contents to the results obtained in a state of suggestibility, increase as it is observed that students of hypnosis are never the subjects thereof, at least at the time being. The psychologist usually must here trust the introspection of his subjects, or place absolute dependence in his own inference on the basis of the mental expressions of the subjects.

Another aspect of these difficulties reveals that they are inherent and irremovable. The development of conscious, or normal memory is necessary for the formation of an individuality, both in sensation, idea, and action. One's name, one's body, one's environment, one's attitude towards the things within that environment, represent a stage of recognition far, far beyond that possessed by the child, for example, and involve a constant dependence upon remembering the respective values of different sense-impressions. Hypnotic memory, on the contrary, arises with all its depression or exaltation, only after the formation of such an individuality, and then, within a short time, runs through the gamut of its manifestations. In other words, the facts under consideration are never discerned through any suggestive treatment of infantile consciousness. It is adult experience that reveals the two types of memory, a condition which all inference should not forget.

There is a certain and a marked amount of volitional control over the course of ideas in normal memory. We can revive images, and so forth, "at will." In hypnotic memory, this control is more or less completely displaced. The mind waits for the operator's suggestions, verbally or otherwise given. Then the ideas appear with automatic regularity and accuracy. The ordinary perceptions by the senses do not apparently fall under this volitional control, as in the perception of a chair, or a piece of colored paper. The unimpaired memory serves as a regulator to perceptual consciousness, and prevents those hallucinations and delusions of perception which mark the mental activity in the trance.

Ordinary memory shows more than merely associative connections in any given remembered series of ideas. Hypnotic memory lacks this continuity, which is of a high intellectual and selective variety. The latter rather follows adhesively the scope and character of the suggestion which serves as the awakening cue, modified, as in all other forms of mental action, by the habits and interests of the individual subject. It is scrappy and patchy It is less dependent upon sensory and motor conditions than normal memory. Sidis's patient "F" remembered that the rella was just long enough for him to finish the third turn in the walk suggested, after which it suddenly fell from his hands. These lapses in the continuity of abnormal memory emphasize its absolute dependence upon the degree of the suggestion. These lapses are sudden and frequent, and limit the intelligent reaction of the subject to his suggestions. There is something analogous to this trait in normal consciousness. All adher-ents of every school of psychology agree in admitting, and truthfully, the fact of the "disappearance of some of the links of consciousness, 'as completely as if they had never formed a part of the series.," But few persons recall when they learned their A, B, C's, or the names of members of the family, etc.

Most of our knowledge is buried in its origin by being assimilated into the very fibres of mental activity. The explanation offered for this phenomenon varies, of course, with the tenets of the respective schools.

Another feature of memory under the conditions of normal consciousness is that the reproductions of past experiences and ideas are notably inexact. Though, for the purpose of our knowledge and our conduct with things and persons these reproductions .are valid and adequate, yet they are, as a matter of fact, fragmentary and symbolical when compared with the fullness and richness in vivacity and content of the original forms of these ideas. Mental life (normally) could not get forward were it impossible to abridge the memories of its past. The chief aim of the processes of ideation is to force the many members of a series of ideas into the fewest possible ideas, which shall literally be representative. In hypnotic consciousness and all weaker forms of susceptibility to suggestion, the reproductions of memory tend to be, and most often are, exact and literal. This is one of the strange and complex effects of suggestion upon mental states of low volitional tone. "Latent memory" (Sir William Hamilton) seems to be most amenable to this condition, in which we secure a "prodigious" (Hudson), but a simple reproduction of past experiences.