Page:Mind (New Series) Volume 12.djvu/126

112 CEITICAL NOTICES. Dr. Mercier's views since the time when he wrote the Nervous System and the Mind, or are merely instances of loose writing. One other important section calls for criticism, the more because in this instance, as in that of ' voluntary action,' the author does but exaggerate an absurd mode of treatment common to many others. He accepts the perfectly sound Spencerian dictum that pleasure- able activities are in general beneficial to the organism while painful processes are harmful; but then, not content with this, he attempts to show that all pleasurable action involves a pre- ponderance of assimilative or anabolic processes, that the pleasure is in fact the direct psychical expression of this preponderance of anabolism. And when any one of the many striking instances to which the rule will obviously not apply occurs to him, he casts about for special explanations. As to the seat of these anabolic processes he is entirely vague, but his general treatment of the subject implies that they occur within the central nervous system if not in other tissues also. What then shall we say of the child that joyously romps until it falls asleep tired out ? Here we have perhaps the most intensely and continuously pleasurable form of activity known to us resulting in exhaustion. All physiologists will agree that in the metabolic processes underlying this activity and especially in those of the nervous and muscular systems katabolism vastly preponderates. No doubt the ultimate effect is usually an increased growth of tissues, but this comes later chiefly during the period of unconscious sleep ; but even this consequent preponderance of anabolism does not always occur. A child, or indeed an adult, may wear itself thin and overtire its nervous system in pleasurable activities. The fact is that there is no evi- dence throughout the whole range of physiology that anabolic processes can determine any form of bodily or mental activity, any setting free of energy, and any such result of anabolism in the animal body is in the highest degree improbable. This treatment of pleasure and pain is but a special instance of a fault that recurs frequently throughout the book. The author, while disclaiming any intention to treat of physiological processes yet frequently uses such phrases as " this is because a mechanism has filled up with motion and discharged itself," or " Sensation corresponds to the reception of motion by the highest nerve regions," or " when motion is impressed upon the animal organism, motion is released from it ". All this is ultra- Spencerian. There may be no appreciable degree of error implied in such phrases but the amount of enlightenment conveyed is equally small. And it is surely a fault that, no one could gather from these pages any hint of the very great increase in our knowledge of the anatomy and physiology of the nervous system brought by the last thirty years. In conclusion it must be said that, in spite of these defects, the book has the great merit that in all its parts it is clearly the pro- duct of much vigorous and thoroughly independent thinking. W. MCDOUGALL.