If we consider memory as a _process_, and not as specific phases of consciousness, we shall find that it is an essential factor in the mechanisms underlying a large variety of phenomena of normal and abnormal life. These phenomena include those of both mind and body of a kind not ordinarily conceived of as manifestations of memory. I would have you dwell in your minds for a moment on the fact that I make this distinction between memory as a process and memory as a phase of consciousness or specific mental experience. What we ordinarily and conventionally have in mind when we speak of memory is the conscious thought of some past mental experience. But when we conceive of memory as a process we have in mind the whole mechanism through the working of which this past experience is _registered_, _conserved_, and _reproduced_, whether such reproduction be in consciousness or below the surface of consciousness. Memory is usually looked upon as something that pertains solely to consciousness. Such a conception is defensible if the meaning of the term is restricted to those facts alone which come within our conscious experience. But when we consider the mechanism by which a particular empirical fact of this kind is introduced into consciousness we find that this conception is inadequate. We find then that we are obliged to regard conscious memory as only the end result of a process and, in order to account for this end result, to assume other stages in the process which are not phases of consciousness. Though the end result is a reproduction of the ideas which constituted the previous conscious experience, this reproduction is not the whole process. More than this, the conscious experience is not the only experience that may be reproduced by the process, nor is the end result always and necessarily a state of consciousness. _Conscious memory is only a particular type of memory._ The same process may terminate in purely unconscious or physiological effects, or what may be called physiological memory to distinguish it from conscious memory. Along with the revived ideas and their feeling tones there may be a revival of the physiological experiences, or processes, which originally accompanied them; such as secretion of sweat, saliva and gastric juice, the contraction and dilatation of the blood vessels, the inhibition or excitation of the heart, lungs and other viscera, the contraction of muscles, etc. These visceral mechanisms, being originally elements in a complex process and accompaniments of the idea, may be reproduced along with the conscious memory, and even without conscious memory. As this physiological complex is an acquired experience it is entitled to be regarded as memory so far as its reproduction is the end result of the same kind of process or mechanism as that which reproduces ideas. Then, again, investigations into the subconscious have shown that the original experience may be reproduced subconsciously without rising into awareness.