2. Vascular reflexes.—Peripheral excitation also has reflex effects on the vaso-motor system; it produces contraction of the spinal arteries, of the carotids, and of the cerebral arteries. Hence the syncope which frequently accompanies acute pain, and the sleep (the result of anæmia) which has more than once been recorded in the case of prisoners undergoing torture. This constriction of the arteries produces a chemical change, a deficit of oxygen and nutritive elements in the cells of the cortex; the respiration of the tissues is interfered with, and the distressed state of the organism is psychologically rendered by pain.
Conversely, the excitations contributing to the wellbeing of the individual are accompanied by a free transmission of nervous force, by vaso-motor dilatation, by hyperæmia of the nervous centres, and, in the motor series, by “aggressive movements,” such as the singing of birds, the joyous barking of dogs, and other analogous manifestations in the human subject.
Meynert—vaguely enough, and relying for support on the association of ideas—has applied his explanation to the case of moral pain. It would not be difficult to adapt this hypothesis to the different forms of vexation and sadness; but with a more complicated mechanism. The point of departure is no longer a perception, but a representation. The phenomenon is no longer of peripheral, but of central origin; so that it starts from the brain and returns to it, or, in psychological terms, begins in a purely intellectual state of consciousness and ends in a state that is primarily one of feeling. If, reading by chance a list of deaths in a newspaper, I find, with no possible opening for doubt, the name of a friend, what takes place in me is this: the other unknown names pass through my consciousness like empty words, or a simple visual percept; suddenly everything is changed; the reflex and vascular movements above described are produced, then the arrest of the medullary and cerebral centres, whose expression in consciousness will be grief. But these reflex actions are only possible if the word read suggests the recollection of former deaths, that is to say, of a sum of privations, negations, and checked desires, the result of a mass of accumulated experiences rising up together and acting, whether consciously, subconsciously, or unconsciously.
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.
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.
Herbert Spencer (followed by Grant Allen, Schneider, and others) has clearly shown that the connection between pleasure and utility, pain and injury, is an almost necessary relation, having its root in the nature of things, and that it has been an important factor in the survival of the fittest. Every animal as a rule persists in actions which cause it pleasure—that is, in a mode of activity which tends to its preservation; while it usually avoids what causes it pain, that being the correlative of injurious actions. The animal has thus two useful guides in the course of its life, to enable it to survive and perpetuate its species.
If this rule were without exception,—if pleasure universally accompanied utility, and vice versâ,—it would be sufficient to state the law of the conditions of existence and nothing more. But the exceptions to the rule are numerous, and require critical study. Some can be explained, others seem to me irreducible to any law.