hold a flower to the nose for long, we become insensible to its scent.  We say of a very brilliant flash of lightning that it blinds us; which means that our eyes have for a time lost their ability to appreciate light.  After eating a quantity of honey, we are apt to think our tea is without sugar.  The phrase “a deafening roar,” implies that men find a very loud sound temporarily incapacitates them for hearing faint ones.  To a hand which has for some time carried a heavy body, small bodies afterwards lifted seem to have lost their weight.  Now, the truth at once recognized in these, its extreme manifestations, may be traced throughout.  It may be shown that alike in the reflective faculties, in the imagination, in the perceptions of the beautiful, the ludicrous, the sublime, in the sentiments, the instincts, in all the mental powers, however we may classify them-action exhausts; and that in proportion as the action is violent, the subsequent prostration is great.

60.  Equally, throughout the whole nature, may be traced the law that exercised faculties are ever tending to resume their original state.  Not only after continued rest, do they regain their full power not only do brief cessations partially reinvigorate them; but even while they are in action, the resulting exhaustion is ever being neutralized.  The two processes of waste and repair go on together.  Hence with faculties habitually exercised—­as the senses of all persons, or the muscles of any one who is strong—­it happens that, during moderate activity, the repair is so nearly equal to the waste, that the diminution of power is scarcely appreciable; and it is only when the activity has been long continued, or has been very violent, that the repair becomes so far in arrear of the waste as to produce a perceptible prostration.  In all cases, however, when, by the action of a faculty, waste has been incurred, some lapse of time must take place before full efficiency can be reacquired; and this time must be long in proportion as the waste has been great.

ii Explanation of Climax, Antithesis, and Anticlimax.

61.  Keeping in mind these general truths, we shall be in a condition to understand certain causes of effect in composition now to be considered.  Every perception received, and every conception realized, entailing some amount of waste—­or, as Liebig would say, some change of matter in the brain; and the efficiency of the faculties subject to this waste being thereby temporarily, though often but momentarily, diminished; the resulting partial inability must affect the acts of perception and conception that immediately succeed.  And hence we may expect that the vividness with which images are realized will, in many cases, depend on the order of their presentation:  even when one order is as convenient to the understanding as the other.