_The Mind retentive in what Sense._--Nor is it altogether proper to speak of retentiveness as a _quality_ of memory--a quality which may pertain to it in a greater or less degree in different cases. The truth is, _all_ memory is retentive, or, more properly, retentiveness _is itself_ memory. It is a quality of mind; a power or faculty possessed in different degrees by different persons; and the power which the mind possesses of retaining thus, wholly, or in part, what passes before it, is the faculty of memory. But in what sense does the mind retain anything which has once occupied its thoughts? Not, of course, in the sense in which a hook retains the hat and coat that are hung upon it, ready to be taken down when wanted. We are not to conceive of the mind as a convenient receptacle, in which may be stowed away all manner of old thoughts, sensations, impressions, as old clothes are put by in a press, or guns in an armory. Not in any such sense is the mind retentive. What we mean, when we say the mind is retentive, is simply this, that it is in its power to repossess itself of what has once passed before it, to regain a thought or impression it has once had. And this is done by the operation of those laws of suggestion already considered. That, and that only is _retained_ by the mind, which under the appropriate circumstances is by the principle of suggestion _recalled_ to the mind. We are not to distinguish, then, the power to retain and the power to recall, as two separate things; nor, for the same reason, can we conceive of a memory that is other than retentive, or that is retentive but not ready. So far as these expressions denote any real distinction, it amounts simply to this, that some minds are more retentive than others; in other words, more susceptible of the influence of the suggesting principle in recalling ideas that have once been before them. Such a difference undoubtedly exists. Some remember much more readily and extensively than others. This may be owing, partly, to some difference of mental constitution and endowment; but more frequently to differences of mental habit and culture. It is not necessary to refer again to the laws of mental reproduction which have been already discussed. It is sufficient to say, that _the more clearly any fact or truth is originally apprehended, and the more deeply it interests the mind_, the more readily will it subsequently recur and the longer will it be retained. IV. MEMORY IN RELATION TO INTELLECTUAL STRENGTH