An English alienist, Clouston, who has published a critical analysis of this hypothesis of Meynert’s, considers it as the best in the present state of the science of nervous physiology, although full of lacunæ, and, after all, rather theoretical than experimental. It is not in accordance with several facts; _e.g._, in anger, which is a painful state, there is an afflux of blood, combined with aggressive movements.[64] On the other hand, it harmonises with a great number of manifestations observed in mental disease; thus, at the third stage of general paralysis, a puncture causes a painless reflex action, because the grey substance, being disorganised, no longer has any inhibitive power. In the evolution of melancholia, the patients sometimes at first suffer from purely physical pains (neuralgia, headache, etc.), which disappear to make way for the melancholic state, which, in its turn, disappears with the return of the physical pain. Everyday experience shows that physical and moral pain cannot coexist in any degree of intensity; a burn may for a time arrest the progress of melancholy, and we all know what happens to many persons as soon as they arrive at the dentist’s. It seems as though the organism had but a limited capacity for either pleasure or pain, and that neither feeling can exist at the same time in its double (physical and moral) form. ----- Footnote 64: _British Medical Journal_, August 14, 1886, pp. 319 _et seq._ We shall see, later on, that the mechanism of anger is not so simple as Clouston seems to admit. ----- II. Much has been written on the finality of pleasure and pain, though two entirely distinct methods of procedure have been adopted. The first, that of theologians and moralists, is an extrinsic explanation; pleasure is an attraction, the charm of life; pain is a vigilant monitor warning us of our disorganisation. They exist in us by the beneficent grace of Providence or Nature; they have a transcendental cause. The second, which has only found complete expression in the evolutionist school, is an intrinsic explanation. It keeps to the analysis of facts, and shows that pleasure and pain have their _why_ in the animal’s conditions of existence, and that consequently their causality is immanent. Thus understood, the problem of _why_ is pretty nearly identical with that of _how_, mechanism and finality being very nearly confounded.