§ 52. =Mood, Passion, Temperament.=—The weaker emotive states, which persist for some time together, are called _moods_; the stronger, which exhaust the organism in a comparatively short time, are called _passions_. No sharp line of distinction, however, can be drawn, either as regards intensity or as regards duration, between these various experiences. We have special names for the =moods= which correspond with most of the emotions; thus, cheerfulness is the mood of joy, and depression the mood of grief. As a rule, the mood appears suddenly, rises slowly to a relative maximum, and then slowly dies down. You wake in the morning, feeling irritable; you proceed to take everything irritably, and so become more irritable still; and after a while the incidents that prompt to irritability seem to grow rarer, and the mood gradually disappears. There are times, however, when some intercurrent event brings about a quick and total change of mood; and there are times when the mood passes off abruptly, without assignable reason; you are surprised to find yourself suddenly cheerful. It is a commonplace that mood depends, in large measure, upon bodily health; but the correlation has not been worked out. Language also has many words for the =passions=: fury is the passion of anger, terror the passion of fear. These states imply a severe shock to the nervous system; and though their first effect is to energise the organism, they must soon exhaust its reserve powers; we notice, in fact, that very violent emotions are likely to give way to lassitude or even to unconsciousness. The name of passion is further given, in ordinary speech, to any abiding interest, natural (p. 207) or acquired,—to any mode of emotive response that is specific and lasting. We say that a man has a passion for success, for science, for gambling; and we mean that a situation which shows any sort of reference to these things will appeal to him, dominatingly and one-sidedly, through that reference.