somewhat different to those which I have used, and, perhaps, with some advantage to the proper subject of our inquiry.

It has been repeatedly stated, that, upon the repetition of any definite sensation, there is not only a renewal of the past feelings with which this sensation was formerly associated, (their renovation taking place agreeably to their prior order,) but that the number of ideas thus renewable may be prolonged to an incalculable extent. I may now add, that the train which is induced only meets with interruption from some new sensation, and with it, from some new succession of renovated feelings. It may therefore be observed, that there is, cæteris paribus, a general tendency in every uninterrupted association of ideas to decrease in vividness, the diminution keeping pace with the extent to which the train is prolonged.

This law will explain the purport of our next investigation, which relates to such incidents of spectral illusions as are connected with the natural tendency of the ideas that form an associated train to gradually fade, or, in other words, to become more faint. I shall therefore proceed upon the general view, that if a train of ideas be not prematurely interrupted, the close of it will always be found to consist of renovated feelings that are too faint to be the object of consci

ousness.

Such being the subject of our present inquiry, a second reference may be made to the foregoing tabular view, which is merely intended to convey a very general notion of the principle I would establish,—that there is a tendency in ideas to fade, the diminution of

vividness keeping pace with the extent to which a series of revived impressions is prolonged. But by consulting the table, it will be seen, that when a train of uninterrupted ideas is, as it were, lengthened out, it must naturally include two varieties of renovated feelings.

Of one variety of ideas the mind is absolutely conscious. This particular variety forms the first, or preceding part of a sequence of renovated feelings.

Of another variety of ideas the mind is unconscious, and this faint description of them is to be found in the remaining part of the train.

I shall next remark, that a cause of mental excitement, adventitious, or truly morbific, may commence its vivifying influence upon the mental feelings during any interval of time that the mind is not susceptible of actual impressions. This operation may then involve any one of the two following circumstances of excitement :

First, An exciting cause may commence its influence, when the ideas, which form the concluding part of an uninterrupted train of renovated feelings, are becoming so faint as to cease being the object of consciousness.

Secondly, An exciting cause may commence its influence more prematurely; or before a train of ideas can have so much decreased in vividness as to cease being the object of consciousness.

These two circumstances of excitement will be considered in succession.

7

SECTION 1.

The Influence of vivifying Causes upon Ideas, of which we should otherwise have been unconscious.

I shall now suppose, that a cause of mental excitement has commenced its influence upon a sequence of ideas, but not until the train has gradually sunk into a degree of faintness so extreme, as to cease being the object of consciousness. A table, the exact reverse of the last given, will then shew the mode in which the concluding part of this train of renovated feelings is liable to such an excitement, as at length to be the object of consciousness.

TABULAR VIEW,

Explaining the Influence of a vivifying Cause upon the concluding Part of a Train of Ideas, of which we should otherwise have been unconscious.

I trust the above table will sufficiently explain the progressive mode, in which a morbific cause of excitement may restore to a vivid state of consciousness faint ideas, of which we should otherwise have been unconscious.

But this effect of a mental excitement will meet with a striking illustration, when we connect it with a law to which I have just adverted, namely, that past feelings, even should they be those of our earliest moments of infancy, never cease to be under the influence of the law of association, and that they are constantly liable to be renovated, even to the latest period of our life, although they may be in so faint a state ás not to be the object of consciousness.

It is evident then, that a cause of mental excitement may so act upon a sequence of extremely faint feelings, as to render ideas of which the mind had long been previously unconscious, vivid objects of consciousness. Thus, it is recorded of a female in France, that while she was subjected to such an influence, the memory of the Armorican language, which she had lost since she was a child, suddenly returned.

With the knowledge of the foregoing fact before us, we shall now imagine, that certain definite ideas are arising in the mind in so vivid a state, that the order of succession in which they formerly occurred as sensible impressions may be distinctly traced. If, then, such ideas are succeeded, no less agreeably to the law of association, by another train, which, having long faded into extreme faintness, are, in the present instance, so morbidly excited as to again become the subject of consciousness,-such revived feelings

will appear to arise in a sort of insulated manner, since their original connexion with recognised sensations may have been long since forgotten. Accordingly this was the case when certain of Nicolai's ideas met with an unexpected renewal of their long-lost vividness; they appeared to be totally unconnected with the regular train of his thought. "I must observe," says this author, "that when I either think deeply on a subject, or write attentively, particularly when I have exerted myself for some time, a thought frequently offers itself, which has no connexion with the work before me, and this at times in a manner so lively, that it seems as if expressed in actual words."

We have next to consider, that the faded ideas of Nicolai's mind, when again becoming the subject of consciousness, had acquired such an extreme degree of vividness as to frequently induce the illusions of phantasms; when, therefore, all knowledge was lost of the original sensations that corresponded to such spectral impressions, no wonder that this writer should express himself after the following manner :"None of the phantasms of my illness were of known places, objects, or persons." And, lastly, when the same metaphysician conducted his inquiry on the principle, that no ideas but those of which we are conscious were subject to the law of association, no small share of disappointment could fail to ensue, when he found himself unable to trace the origin of his phantasms to former impressions made in the usual manner upon his senses.