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all over the world. Among Londoners the decline withage is apparently- much greater in the earlier yearsand a little less in the later years than the uniform rateof 3% per decade. Thus a 10-year-old London boyhas a B.M.R. 28% higher than that of a 30-year-oldman. Similarly the B.M.R. of a London woman of anyage is higher than the international average ; it is

about nine-tenths of the B.M.R. for a man. Are these

significant physiological differences or the consequencesof experimental error ? Predictions-of the B.M.R. fora few normal men and women of varying ages andsizes indicate that the London standards are usually3-7% lower than the compound international standard.Is this a true local distinction ? We may never getprecise answers to these questions ; though, if theissue is simply one of accuracy, our judgment wouldbe in favour of the highly standardised technique ofone skilled investigator.

It is certain that in future clinical pathologists inthis country will use RoBERTSON and REID’S stan-

dards, and that international food planners willuse those of the Commonwealth Bureau ; and eachwill have a closer approximation to the true answerthan the previously accepted figures. The dis-

crepancies between the two are unlikely to prove ofgreat practical significance ; and they can only beresolved by further observation and statistical analysis.Meanwhile we congratulate those who have workedwith such thoroughness to establish both standardson the careful way in which they have sharpened theprecision of fundamental physiological knowledge.

1. The Contribution of Medicine to our Idea of the Mind. Deliveredat Cambridge on May 7, 1952. London : Cambridge UniversityPress. 1952. Pp. 30. 2s. 6d.

Ideas of Mind’’WHAT is mind ? No matter," the old joke runs.

"What is matter ? Never mind." These, like manyother age-old assumptions, have lately begun to

crumble in the foundations. For what do we know ofmind but that we experience part of its activities

consciously, and that it is associated in some waywith events in the brain ? And how can we be surethat matter, which has dislimned into energy, is notan aspect of mind ? Sir RussELL BRAIN assuredthose who heard his Rede lee ture 1 that we are stillfar from being able to settle these questions.In the last fifty years, he pointed out, medicine

-particularly in its branches of neurology and

psychiatry-has been actively changing our idea ofthe mind. Everyone knows that the brain influencesthe mind : the effects of drink, drugs, or a blow onthe head demonstrate as much. Studies of diseasesof the brain have contributed greatly to our know-ledge of brain-mind relationship, and one strikingdiscovery has been that the mind does not behavelike something homogeneous. Damage to any partof the brain might be expected to make the mind ingeneral less efficient ; but, as we know from the resultsof destructive lesions, damage sometimes leaves theintellect untouched while changing the emotional lifeof the subject in such a way that his feelings for,and behaviour to, others are grossly abnormal.Again, the electro-encephalograph has revealed normaland abnormal electrical rhythms in the brain ; andabnormal rhythms are - sometimes found in peoplewho have lapses-usually regarded as moral lapsesŇ

in the way of outbursts of temper or violence, or

irresponsible behaviour. 0This has important implications for our ideas of

criminal responsibility. The law is based on thebelief that the will is free : that man has the powerto distinguish and choose between good and evil; so

that if he does an evil thing he must have chosen todo it and can be held responsible. These principlesare expressed in the McNaughten rules, which laydown that a person is to be held responsible for hisact unless at the time when he did it, by reason ofdisease of mind, he either did not know the natureand quality of his act, or did not know that it waswrong. Neurophysiologists, however, can show thatsometimes evil behaviour-such as a tendency toviolent outbursts-is associated with recordableevidence of abnormal brain function ; and modernpsychiatrists find that a man who can distinguishgood from evil may not always be free to choosebetween them. But it is one thing for doctors torecognise that a man’s power to abstain from anevil act may be seriously impaired ; it is quite anotherto bring this concept into a court of law. For thereare-or so most of us think-sinners as well as sickmen ; and it is not easy for either lawyers or doctorsto draw the line between pathological lack of self-control which does not deserve punishment- and sinfullack of self-control which does. Perhaps, BRAINsuggested, the difficulty arises because of the retri-butive nature of punishment, which makes it necessaryto assess responsibility : it would often be easier, hethinks, to decide whether a criminal was so mentallyabnormal that he needed to be shut up for the

protection of society, than to decide whether he was,through mental disease, so lacking in self-control thathe deserved to escape punishment.Apart from abnormal behaviour due to abnormal

states of the brain, can the mind itself fall sick, ordevelop a pattern of thinking so far out of the truethat it influences behaviour ? In many forms of

psychosis no gross brain abnormalities -are found toaccount for the sick-thoughts of the patient ; but this

may be merely because the lesion is too fine to bedetected by our present methods, or because it is

primarily a lesion in other organs than the brain-perhaps in the endocrine system. Nevertheless,while neurophysiologists and neuropsychiatrists havebeen concentrating on the physical basis of mind, aschool of psychological thought has grown up whichseeks to explain many forms of mental abnormalityin psychological terms, and here again the study ofthe abnormal has thrown much light on the normal.BRAIN illustrated this -development from Freudianpsychology, because FREUD’S" fundamental principleshave been accepted far beyond the limits of hisown school, and now form part of the equipment ofmost eclectic medical psychologists." FREUD intro-duced the idea that the mind can be analysed, andthat it then appears to be composed of parts whichbehave as though they were autonomous, or semi-autonomous. He maintained that experience fraughtwith strong emotion might continue to influencebehaviour, even when- forgotten ; and that feelings- such as anxiety-might persist, detached from theideas which gave birth to them, or even attachingthemselves to objects or circumstances ’with whichthey had originally nothing to do. Human behaviour,

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he believed, is sometimes, at least, the resultant offorces which, though perhaps not actually’measurable,can be considered in quantitative terms. *’ We feel

justified in regarding emotion," FREUD said, " as a

quantity which may become increased, derived, or

displaced." These emotional forces might be in

conflict, and they might sometimes act on the subjectin such a way as to determine his behaviour, eventhough he knew nothing about them consciously.This concept, too, strikes a blow at human responsi-bility, or at least poses some new ethical problems :what, for instance, is the moral position of a

young woman who develops a hysterical paralysiswhich disables her from looking after an invalidmother ?

Thus we have been watching in this century,BRAIN said, the growth of two independent and verydifferent explanations of mental states, which havein common only the disquieting suggestion that weare not such responsible parties as we thought wewere. On the one hand the neurophysiologists andneuropsychiatrists are tending more and more to

regard states of mind as caused by states of thebrain ; on the other hand, the analysts explain statesof mind as the outcome of the interplay of psycho-logical forces. Either they cannot both be right, orelse there must be some logical expression of theirrelationship with one another. This brings us backto that same door wherein we went ; for either wemust believe that brain and mind are two thingssomehow related to one another, or they are two

aspects of the same thing : we must, in short, bedualists or monists. SiiERRiNGTON, who was a dualist,believed that mind could never be explained in termsof matter, because the two are incommensurable.BRAIN thinks that we might perhaps get round thedifficulty by altering the way we word our questionsabout it. Perhaps it makes sense to say that a

certain state of the brain is not the caeuse of a painor an idea but actually is a pain or an idea ; andthe feeling of pain, or the comprehension of the idea,is an experience’ of the person whose consciousnessis related to that particular brain. The electrical

pattern which we are trying to identify with theseexperiences is only a symbol for describing thebehaviour of the brain as it might be observed bysome other person with the necessary instrument.After all, as Sir RUSSELL has explained on a previousoccasion,2 the receptive function of the brain is to

provide us with a symbolic representation of the

physical world outside. If the only symbolic repre-sentation we can get of another person’s idea is theelectro-encephalogram produced by an electrical

pattern in his brain-well, there it is : that is howsomeone else’s idea looks to us. Fortunately we canalways ask him how it looks to him ; and since he

experiences it directly he is in a much better positionto describe it.

Ingenious as this monistic way of resolving thedifficulty seems, it is apt to trickle through the headlike water through a sieve leaving not so much as anelectrical pattern behind. BRAIN himself seemedrather dissatisfied with it, for he hastened to pointout another objection to monism. Before a feelingenters consciousness, nerve-impulses travel along

2. Lancet, 1951, ii, 1073.

relays of fibres, and during this process there is nofeeling at all ; and if the pathway is blocked at anypoint there never is any feeling. " So consciousnessis not a property of all nerve fibres, even when theycontribute to it : why, then, should it be related tosome fibres and not to others ? If mind and brainare two aspects of the same thing we might haveexpected that all brain-events would also in some

way be mind-events, but this is not so, and we donot know why." Perhaps, he added hopefully," brain-mind relationship will have to be expressedin terms of a space and time different from thoseof our naive experience." The space in which ourmind exists may not be identical with the space inwhich we perceive the nervous system. Perhaps itstime is different too, for it seems that a sensationmust have a certain duration if it is to be perceivedat all : it is experienced only when a three-dimensionalevent persists for a minimum time. If so, a three-dimensional account of events in the brain wouldnecessarily seem incommensurable with mind. Yield-

ing cautiously to a more popular view of the problem,the lecturer described mind as the great amphibian,linked through the brain to the world of matter, butmoving in its own sphere as though it could soarabove the physical. Yet (he reminded his hearers)how vulnerable is this nying-nsh : for a mindless

agent-a germ, a drug, a weapon-can destroy it.Even the will, the very stronghold of mind, can beviolated, as we have lived to see, so that a man willaccept ideas he would normally reject, and confessto offences he has not committed.We have much to learn ; but meanwhile BRAIN

warns us not to pursue either the physical or thepsychological causation of mental states to theexclusion of the other. " Until the logic of theirmutual relationship is established, the physical andpsychological treatment of mental disorders should bejudged by their results, rather than by the theoreticalexpectations of their exponents."

1. Health of the School Child. Report of the Chief Medical Officerof the Ministry of Education for 1948 and 1949 ; p. 16.

Synergy of Health and EducationTHE future historian, looking back on our Welfare

State, may wonder why we were willing to spend almostas much money on treating sickness as on educatingour children. He may even conclude that we had not

yet recognised the interdependence of health andeducation-how the well-being of the child assiststhe teacher’s task and a wise upbringing forms thefirmest foundation for a healthy life. In theory ouraims seem sound enough—JUVENAL summarised them1800 years ago as mens sana in corpore sano-but

practical application lags sadly behind. Our growingcontrol over epidemic diseases and the rapid reductionin severe poverty should have allowed us to embarkon a more constructive policy for health ; and schoolsare among the most important means at our disposalfor promoting fitness of mind and body. The school,indeed, should be a place where children " gainphysical power as well as academic knowledge."1 Yetall too many of our school buildings still stand as

grim memorials of the grudging attack on illiteracyof fifty years ago. It is difficult to teach anything,and impossible to teach healthy ways of living, in