tional activity is modified by structural changes. There is not a new line of thought instituted, leading in opposite directions to the normal thought, but a misdirection of the ordinary mental processes. There is, however, a certain amount of illusion which, when pronounced, or when the effect upon the brain-cells is such as to cause an evolution of distinctly-erroneous thought, or actual hallucinations, indicates that the frontier of sanity is crossed.
Such considerations will enable us to observe and to comprehend that initiatory stage of mental impairment which precedes obvious and well-marked dotage. The earlier stages, the lighter shades of mental failure, of waning brain-power, are distinct enough to the trained eye, long before those more obvious changes are reached which are recognized by the untrained observer. Such mental changes are commonly found in those undergoing degenerative physical changes, not only in the very aged, but in those passing into premature decay; in fact, mental impairment and decay are but the evidences or outcomes of the implications of brain-tissue in the general degeneration. We are, of course, most familiar with such changes in the very old, in whom we regard them as almost normal. The mental grasp is imperfect and illusive; petulance and caprice are the characteristics, especially of those in whom the intellect was never very strong. Their intellectual vision is deceptive and untrustworthy. A dim consciousness of some such change obtains in the mind, and makes them deeply suspicious and extremely susceptible, and ready to take offense at the slightest indication by others of a knowledge of their growing incapacity. Nor can we feel surprised at this sensitive suspiciousness. Mental decay cannot be a pleasant matter for those undergoing it, and no wonder they are excessively jealous of any alteration of manner or attitude.
A similar condition of enfeeblement, combined with excessive jealousy and deep-rooted suspicion, is furnished by those who have anticipated the normal time of senile decay by habits of drunkenness. The man who is beginning to yield under persistent alcoholization, and who feels that his powers are giving way, is generally suspicious and jealous, if not actually malicious. The intellect undergoing premature degeneracy is more readily and easily provoked than is that of a person entering normal dotage; while there is often coexistent a certain amount of spasmodic vigor of temporary active irritability. Such persons are simply dangerous to those dependent upon them, and not to be trusted—their mischievousness being only restrained by their incapacity to execute or put in force their malicious designs.
There are two other mental attitudes which are not directly associated with bodily disease, but which exercise so distinct an influence over physical conditions, especially in sickness, that they may not improperly be considered here, though not quite falling within the scope of this paper. One is that condition of mental impairment in which
