September 9, 1922] 



NA TURE 



35i 



organ, tend more to one half or the other and in man's 

 cerebrum the preponderance of one-half, namely, the 

 left, over the other may be a sign of unifying function. 



It is to the psychologist that we must turn to learn 

 in full the contribution made to the integration of the 

 animal individual by mind. But each of us can recog- 

 nise, without being a professed psychologist, one 

 achievement in that direction which mental endowment 

 has produced. Made up of myriads of microscopic 

 cell-lives, individually born, feeding and breathing 

 individually within the body, each one of us never- 

 theless appears to himself a single entity, a unity 

 experiencing and acting as one individual. In a way 

 the more far-reaching and many-sided the reactions of 

 which a mind is capable the more need, as well as the 

 more scope, for their consolidation to one. True, each 

 one of us is in some sense not one self, but a multiple 

 system of selves. Yet how closely those selves are 

 united and integrated to one personality. Even in 

 those extremes of so-called double personality one of 

 their mystifying features is that the individual seems 

 to himself at any one time wholly either this personality 

 or that, never the two commingled. The view that 

 regards hysteria as a mental dissociation illustrates the 

 integrative trend of the total healthy mind. Circum- 

 stances can stress in the individual some, perhaps lower, 

 instinctive tendency that conflicts with what may be 

 termed his normal personality. This latter, to master 

 the conflicting trend, can judge it in relation to his main 

 self's general ethical ideals and duties to self and the 

 community. Thus intellectualising it, he can destroy 

 it or consciously subordinate it to some aim in harmony 

 with the rest of his personality. By so doing there is 

 gain in power of will and in personal coherence of the 

 individual. But if the morbid situation be too strong 

 or the mental self too weak, instead of thus assimilating 

 the contentious element the mind may shun and, so to 

 say, endeavour to ignore it. That way lies danger. 

 The discordant factor escaped from the sway of the 

 conscious mind produces stress and strain of the con- 

 scious self ; hence, to use customary terminology, dis- 

 sociation of the self sets in, bringing in its train those 

 disabilities, mental or nervous or both, which charac- 

 terise the sufferer from hysteria. The normal action of 

 the mind is to make up from its components one unified 

 personality. When we remember the manifold com- 

 plexity of composition of the human individual, can we 

 observe a greater example of solidarity of working of an 

 organism than that presented by the human individual, 

 intent and concentrated, as the phrase goes, upon some 

 higher act of strenuous will ? Physiologicallv the 

 supreme development of the brain, psychologically the 

 mental powers attaching thereto, seem to represent 

 from the biological standpoint the very culmination of 

 the integration of the animal organism. 



The mental attributes of the nervous system would 

 be, then, the coping-stone of the construction of the 

 individual. Surveyed in their broad biological aspect, 

 we see them carrying integration even further still. 

 They do not stop at the individual; they proceed beyond 

 the individual ; they integrate, from individuals, com- 

 munities. When we review, so far as we can judge it, 

 the distribution of mind within the range of animal 

 forms, we meet two peaks of its development — one in 

 insect life, the other in the vertebrate, with its acme 



NO. 2758, VOL. I IO] 



finally in man. True, in the insect the type of mind is 

 not rational but instinctive, whereas at the height of its 

 vertebrate development reason is there as well ;is 

 instinct. Yet in both one outcome seems to be the 

 welding of individuals into societies on a scale of organ- 

 isation otherwise unattained. The greatest social 

 animal is man and the powers that make him so are 

 mental ; language, tradition, instinct for the preserva- 

 tion of the community, as well as for the preservation of 

 the individual, reason actuated by emotion and senti- 

 ment, and controlling and welding egoistic and altruistic 

 instincts into one broadly harmonious, instinctive- 

 rational behaviour. Just as the organisation of the 

 cell-colony into an animal individual receives its highest 

 contribution from the nervous system, so the further 

 combining of animal individuals into a multi-individual 

 organism, a social community, merging the interests of 

 the individual in the interests of the group, is due to the 

 nervous system's crowning attributes, the mental. 

 That this integration is still in process, still developing, 

 is obvious from the whole course of human pre-history 

 and history. The biological study of it is essentially 

 psychological ; it is the scope and ambit of social 

 psychology. Not the least interesting and important 

 form of social psychology is that relatively new one, 

 dealing with the stresses and demands that organised 

 industry makes upon the individual as a unit in the 

 community of our day and with the readjustments it 

 asks from that community. 



To resume, then, we may, I think, conclude that in 

 some of its aspects animal life presents to us mechanism 

 the " how " of which, despite many gaps in our know- 

 ledge, is fairly explicable. Of not a few of the processes 

 of the living body, such as muscular contraction, the 

 circulation of the blood, the respiratory intake and out- 

 put by the lungs, the nervous impulse and its journey- 

 ings, we may fairly feel, from what we know of them 

 already, that further application of physics and 

 chemistry will furnish a competent key. We may 

 suppose that in the same sense as we can claim to-day 

 that the principles of a gas-engine or an electro-motor 

 are comprehensible, so will the bodily working in such 

 mechanisms be understood by us, and indeed are largely 

 so already. It may well be possible to understand the 

 principle of a mechanism which we have not the means 

 or skill ourselves to construct ; for example, we cannot 

 construct the atoms of a gas-engine. 



Turning to other aspects of animal mechanism, such 

 as the shaping of the animal body, the conspiring of its 

 structural units to compass later functional ends, the 

 predetermination of specific growth from egg to adult, 

 the predetermined natural term of existence, these, and 

 their intimate mechanism, we are, it seems to me, 

 despite many brilliant inquiries and inquirers, still at a 

 loss to understand. The steps of the results are known, 

 but the springs of action still lie hidden. Then again, 

 the " how " of the mind's connexion with its bodily 

 place seems still utterly enigma. Similarity or identity 

 in time-relations and in certain other ways between 

 mental and nervous processes does not enlighten us as 

 to the actual nature of the connexion existing between 

 the two. Advance in biological science does but serve 

 to stress further the strictness of the nexus between 

 them. 



Great differences of difficulty therefore confront our 



