DISCOVERY 



79 



stances, in order to be able to bring all its forces to bear 

 upon any one particular problem. With the diversity 

 we are familiar enough. The unification, however, is 

 not so familiar. A very specialised method for achieving 

 it is seen in the ductless glands of vertebrates ; more 

 primitively, we can simply say that each part has a 

 reaction upon every other part, whether chemically or 

 mechanically, so that the whole is not merely the sum of. 

 the parts, but the sum plus the interaction of the parts. 

 This has long been known ; but the relation by which a 

 higher, controlling portion regulates and inhibits the rest 

 — this has only recently come to the fore as a general 

 principle of biology. 



In a worm the front end of whose body has been cut 

 off. the first structure to regenerate is a head ; this once 

 formed, the other missing organs are formed in due 

 relation to and at normal distance from this head. But if 

 we prevent the formation of a head, as we can by cold 

 or by narcotics, the rest of the missing organs will never 

 form. In a similar way, in the normal man there are 

 certain reflexes which the spinal cord will carry out. 

 When the connection between cord and brain is severed, 

 these reflexes disappear, and, as Head and Riddoch 

 have shown, quite new and much more primitive reflexes 

 (of the sort that characterise toads and other low verte- 

 brates) take their place. How is this possible ? Kormallj', 

 the reflexes are compounded of the activities of the spinal 

 cord and the controlling influence of centres in the 

 brain : remove the latter, and the unmodified activity 

 of the cord appears as something new. 



Many other parallels could be drawn, particularly 

 between dedifferentiation, when whole organisms revert 

 to a simpler stage, and regression, when human minds 

 run back to the state they exhibited in childhood : but 

 space forbids. The comparison is of value, however, for 

 it demonstrates — w-hat specialisation is always doing its 

 best to obscure — the essential unity of all life. 



The bulk of Dr. Rivers' book is devoted to the different 

 types of neurosis and psychosis — anxiety-neurosis or 

 neurasthenia, hysteria, dissociation, regression, phobia 

 due to repressed complexes, and so forth, with a discussion 

 of the underlying concepts — of instinct, suggestion, 

 suppression, sublimation — on which he bases his analysis. 



In accordance with the dynamical idea set out above, he 

 considers all the abnormal mental conditions as upsets 

 of equilibrium which represent crude and inadequate 

 methods of attempting to solve a conflict between parts 

 of the mind. The properly-developed mind is one in 

 which every part, even the " lowest " instinct, is strong 

 and active, but every part is properly subordinated in 

 its due place in the hierarchy. An instinct is only bad 

 when it escapes from control. Repression of primitive 

 instincts and emotions is a mei'e drj-ing of the springs of 

 action. It is when instincts are powerful but sublimated 

 rightly — piped ofi to drive the wheels of intellect and will 

 — that real health of mind is found. 



There is one general criticism which may be raised. 

 It is a curious commentary on the method by which 

 science progresses that the psychologists and physiologists 

 are now laying that great emphasis upon adaptation 



which they deplored in the biologist forty years ago. 

 The biologist meanwhile has moved on, and, while fully 

 conscious of the importance of the adaptation-concept, 

 is finding that much of what he thought at one time to be 

 adaptive is in reality a direct and necessary consequence 

 of the constitution of living matter. Dr. Rivers thinks 

 of the psychological mechanism of suppression as having 

 come into existence in response to a need for more delicate 

 graduation of response in some cases, for immobility in 

 others ; he looks for the cause of dissociation in the 

 alternation of land and water in the life of Amphibia. 

 There is much to be said for this view : but the future 

 will probably show that it is not the actual mechanisms 

 which have originated thus, but only specialised conditions 

 of the mechanisms, which themselves are inevitable 

 by-products or ingredients of a highly-organised nervous 

 system. 



An analogy from biology will make my meaning clear. 

 The property of regeneration is obviously useful to the 

 organisms which possess it. Which of us would not like 

 to be able, if we lost a hand or a head, to grow a new 

 one ? During the latter half of the nineteenth century it 

 was strenuously maintained by leading zoologists that 

 the power of regeneration was adaptive, and had origi- 

 nated during evolution through natural selection. A 

 careful study, however, of the method and occurrence 

 of regeneration has shown that this is not so. Regeneration 

 is an inherent property of life, a necessary outcome of 

 the fact that an organism is a system in equilibrium, and 

 that, w-hen that equilibrium is upset by the removal of 

 a part, it is re-established in the same way as is a chemical 

 equilibrium. Later on, in some organisms, this power 

 has been specialised, adaptively, while in others it has 

 bsen sacrificed to more important qualities. 



Mental dissociation is probably a close parallel. Given 

 a psycho-neural system capable of associative memorj', 

 a break between one part of the system and another may- 

 be made by various agencies ; and if this happens, the 

 two divided parts will round themselves off into a con- 

 dition of equilibrium and be capable of a more or less 

 independent existence : the possibility of dissociation 

 is given by the nature of the system itself. No doubt 

 but that machinery for more prompt and efficient 

 dissociation (as in animals exhibiting immobility in 

 response to danger) will be later developed through 

 natural selection. Similarly with hypnotism. Given 

 some mechanism of suppression and of suggestion, a 

 large part of the phenomena of hypnotism follow naturally, 

 without our having to ask what the biological meaning 

 of hypnotism may be. 



This is not to detract from Dr. Rivers' brilhant use of 

 the biological method, which illuminates biology equally 

 with psychology : it is merely to point out a limitation 

 and to suggest another view-point which, as a matter of 

 fact, has abundantly justified itself by results in the 

 parallel but more developed science of biology. 



Ur. Rivers' judicial view of the position of Freud and 

 his theories in modem psychology will, it may safely be 

 asserted, prove to be that which will be adopted by the 

 historians of science. The experience of the war has 



