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HUNTERIAN SOCIETY

INTRODUCING a discussion on March 16th ata meeting of this society (Dr. W. BRANDER, thepresident, being in the chair) on the subject of

FatigueDr. ADOLPHE ABRAHAMS said that among the presentingsymptoms for which practitioners were most commonlyconsulted were tiredness, or one of its equivalents,lack of energy, premature exhaustion, undue fatigue,lassitude. Certain serious pathological states-myas-thenia gravis, Addison’s disease, malignant disease,Addisonian anaemia, diabetes, tuberculosis, post-influenzal debility-were accompanied by asthenia.But the majority of patients who complained ofchronic fatigue were not suffering from any seriousor indeed any disease at all, nor as they alleged fromover-work ; they were simply bored. Yet it was amatter of common experience that the amount ofcongenial work which even an average person couldundertake was colossal. Dr. Abrahams here relateda personal experience." When I was a house surgeon at St. Bartholomew’s,"

he said, " the practice-whether or no it obtains to-day-was to go on full duty every week-end in five, when frommidday Friday until midday Tuesday you were responsible,in addition to your routine duties, for every surgicalemergency. I recall one such full duty when throughcontinuous pressure I never completely undressed duringthe four days and nights. It happened moreover thatfor most of that week-end there was a dense fog, and asa consequence I lost all distinction between day andnight, all conception of time. I experienced a sense

not of fatigue but of supreme happiness, the memoryof which persists to this day. I recall a similar experienceduring the war ; but it is superfluous to elaborate whateveryone here has also encountered: periods of con-tinuous intense work congenial and satisfactory to becontrasted with the sense of exhaustion only too inevitablewhen the work, though far less exacting, is of a naturewhich is for one reason or another uninteresting andunprofitable."We were all agreed, Dr. Abrahams continued,

that work as such never caused a breakdown ; somemental conflict must be present. Of course whenpatients came with the story of recent gross reductionin their ability to undertake exertion, physical ormental, it was natural to try to identify some

responsible toxin, acting as a brake upon the machineryof activity. We admitted the influence of certain

accepted toxins-tuberculosis, malignancy, influenza-but what were we to say of the more elusive toxinsin focal sepsis ? Once determined to incriminatesome such abnormality and having excluded theaccessible teeth, tonsils, sinuses, prostate, gall-bladder, appendix, and pelvic organs, there remainedthe almost unlimited field provided by the alimentarycanal. Contemporary advertisements discovered herethe invariable cause of tiredness and sought its curein suitable pabulum or the eradication of intestinalpoisons. But both the scientifically minded physicianwith his toxins and the more matter-of-fact practi-tioner who accepts the idea of boredom must notforget the psychologist who finds in fatigue a defenceagainst anxiety or the undertaking of responsibilityor even Nature’s protection against over-exertion.

Dr. Abrahams then turned to the problem of fatigueas an accepted physical consequence of muscularexercise. Fatigue is due to exhaustion of thesubstances required for the supply of energy or moreexactly to the accumulation of sarco-lactic acid,the excess which the blood stream is unable to washout. If exercise is of such severity that the lactic

acid produced is no more than can be removed

simultaneously by oxidation-accepting as themaximum intake of oxygen four litres a minute-fatigue will not occur until other factors of exhaustionenter into the problem. But with really violentexercise the generation of lactic acid is far tooconsiderable for its elimination-e.g., in the case ofa sprinter, 1 gramme of lactic acid accumulates for

every stride taken, i.e., 40 grammes in the hundredyards. Athletic training to some extent consistsin perfecting the circulation for the removal of lacticacid, but it also embodies the education of the musclesto neutralise fatigue products or perhaps to toleratetheir presence. The great athlete, Dr. Abrahamsthinks, has muscles constitutionally superior in thisrespect. Perhaps the maximum accumulation oflactic acid possible to the most highly trainedindividual is 120 grammes. Furthermore the capacityto resist fatigue is bound up with the willingness topush oneself to the last degree ; the seat of fatigueis in the nervous system and the available reserveis immeasurable. In long-continued exercise ofsub maximal severity, fatigue may be due to shortageof fuel. American experiments upon marathonrunners had shown an exact correlation betweenexhaustion and hypoglycaemia which Dr. Abrahamshad been unable to confirm. But exhaustion duringa substantial athletic effort was a disturbed mechanismconcerned with several widely different factors;for in addition to the shortage of fuel, to the accumula-tion of lactic acid, to the element of monotony,there was the prevention of loss of heat and of moistureunder certain unfavourable conditions. The lassitudeoften experienced on the day or days following asevere effort had been attributed to myocardialweakness and the same explanation had been appliedto the incapacity for effort after bacterial illness,especially influenza. " I am unable," he said," to agree that any direct cardiac association needbe invoked. After all, the muscular metabolitesmust have an effect upon the central nervous sytemand to this I attribute protracted and delayed fatigue,and, I may add, the symptoms which are on insufficientevidence accepted as ’heart-strain’."

1B,f""1;B1BTfP A T 1 A TTrTTIzMENTAL FATIGUE

Dr. C. S. MYERS, F.R.S., said that fatigue isusually defined as "that state of lessened activityof an organ which results from its previous activity."But so varied are the effects of prolonged mentalwork, so complex and so widespread is the " organ

"

of mind, and so ignorant are we of the nature ofmental activity that a correspondingly succinctdefinition of mental fatigue would fail to serve anyuseful purpose. On grounds of physiological analogy,we might at first be disposed to attribute mentalfatigue to the exhaustion of locally available mental"energy." But the only apparent evidence that wehad of such a cause of mental fatigue related tostructures outside the central nervous system-namely, in the effects on consciousness produced bystimulating the " protopathio

" or " spot "

systemof sensibility. These effects were easily observablein the skin ; where, if any one heat spot or coldspot is re-excited immediately after its previousstimulation, it would fail to elicit a second sensation.Its previous response, comparable perhaps to an

explosion, had apparently resulted in completeexhaustion : rest is needed for its recovery. Butthere were other sensations, if not too intense, whichseemed virtually indefatigable. We can listen almosteternally to the gentle ticking of a clock or endure,likewise without apparent sensory fatigue, the

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continuous daylight of a northern summer. Thereare other prolonged but more intense sensations-e.g., the hearing of a continuous loud tone, which,while not suffering appreciable change themselves,nevertheless-owing, it is believed, to central inhi-bition-result in a rise of the threshold of hearingfor tones of the same and of neighbouringpitch. So far as cerebral fatigue is concerned,it might be wondered whether any impairment ofmental activity would be expected either throughthe exhaustion of locally available energy or throughthe accumulation of toxic influences due to its exer-cise. Conscious processes however seemed to involvethe activity of extensive areas of the brain functioningas a whole; the notion of " centres of conscious-ness

" was fast becoming obsolete.

Uninterrupted concentration at any task, Dr.

Myers said, is unnatural; it is our nature to take

repeated brief rests during any long period of mentalwork. But whereas the uninterrupted maintenanceof mental activity in one particular field of attentioncannot endure for long, the freer play of phantasyin day-dreaming and in sleep seemed untiring.Feelings of mental weariness are not invariablya faithful index of mental impairment; lessenedoutput of mental work may indicate that we arementally fatigued without our necessarily feeling so,or we may feel mentally fatigued without necessarilyshowing it in poorer work. Measurement of the

output of work was at present our most trustworthyindex of mental fatigue, for unfortunately we haveno sufficiently reliable objective tests of mentalfatigue. Purely physiological tests have proved oflittle use. Periodically interpolated mental testsare at the mercy of the will and of the feelings of thesubject; they are also subject to the effects ofpractice and of consequent automatism ; and theydiffer, owing to their necessary simplicity, from themore complex directive, aim-seeking characters of

higher mental work. There can however be no

doubt that, in general, the efficiency of performingcertain interpolated mental (e.g., arithmetical) testsis lowered by continuous mental work. Both the

feeling of mental fatigue and fatiguability showedvast individual differences. The obsessional type ofpsychoneurotic might be kept by his abnormallystrong perseveration incessantly at work when thenormal worker would be unable to resist from takingprotective rests. Especially he, but also even thebest balanced and most vigorous person, under

sufficiently prolonged or intense mental activitywould ultimately suffer, sometimes quite suddenly,from pathological fatigue or so-called mental break-down. Extreme muscular fatigue had never beenshown to cause mental breakdown.Some light was thrown on the pathology of mental

breakdown by considering the effects of prolongedactivity at the lowest levels of the central nervoussystem. As the spinal flexion reflex tires under con-tinuous excitation or frequent excitation, it becomesweaker and more tremulous, and may finally evencease altogether. But during this fading there occurbrief periods of intermission and even of replacementby the antagonistic response of extension ; inhi-bited movements are more ready to break through.The same occurs when we are at work in some parti-cular field of mental activity. Antagonistic andirrelevant fields of attention are successfully inhi-bited, at first without voluntary effort owing to theincentive of interest, but later, as interest wanes andboredom enters, through the exercise of volition.

Finally as this directive activity of the will fails

through fatigue, we can no longer, despite the utmost

effort, attend to the work on which concentrationis required. Thus local boredom gives place to generalfatigue. Continued cortical stimulation of theflexor area results in a facilitated increasing response,then to a rise in sensitivity of the antagonistic extensorarea, and finally to a quasi-epileptiform wave ofmovement spreading to neighbouring motor areas.These changes were in some aspects analogous tothe collapse of the higher coordinating centres andto the wasteful dissipation and short-circuiting ofenergy, characteristic of mental breakdown throughoverwork.

It seems, Dr. Myers concluded, that mental fatigueis most evident and serious when the work is of akind that demands concentration of attention, andthat then its most prominent feature is a collapseof "directive activity" which manifests itself inimpairment and distraction of attention, loss ofskill and deficient effort, in irritability and othersymptoms of loss of self-control, and finally in moreserious disorders of volition, cognition, and emotion.But in addition to such fatigue of volitional direction,there is likewise a fatigue of the mental processeswhich are subject to such direction.

But, he added, we do not know what occurs whenfatigue sets in. We may conjecture that synapticresistances are increased, or that adverse chemicalbodies are formed, like acetylcholine, neurogenic andhumoral in nature, or resembling in their action thetoxins generated, by excessive muscular activity.It may also be that antitoxins can be formed, resistantto such fatigue. But we are as ignorant of these aswe are ignorant of the supposed toxins and anti-toxins responsible for, or defensive against, sleep.We are also ignorant of the differences which arelikely between the fatigue caused by intensive orprolonged mental work and the fatigue caused bydeprivation of sleep.

FATIGUE IN INDUSTRY

Dr. J. C. BRIDGE said that in his visits to centresof industry he had been impressed by the ability ofworkers to continue at heavy tasks for eight or morehours every day of the working week ; he felt surethat part of the explanation lay in the fact that thework was not actually continuous, but the men had" breathers," intervals of rest between the tasks.Mechanisation too in recent years had done much toreduce the muscular energy necessary at many ofthe heavier kinds of work. He assumed there wasa physiological fatigue which was good and healthy,but he knew of no means of determining subjectivelywhere this ended and pathological fatigue began.A recent move was to substitute for three eight-hourly shifts four six-hourly ones; one result ofthat change had been to increase the output. Repe-titive work in attending to machines of uncannycomplexity must produce in the worker a sense ofboredom or fatigue. In making clothing the com-ponent articles were sent along on a continuousband ; workers along its path had a set piece ofwork to finish before the garment was passed on tothe next. That kind of monotony was well calcu-lated to produce fatigue. When intervals of restwere allowed, many of the women occupied them-selves with knitting ! He could only presume thatno more than a small part of the human anatomybecame fatigued by the work. Fatigue in industryhad been for some time diminishing, and was still

being reduced, but its form varied owing to the

changing forms of employment. Study of thesewas important.

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DISCUSSION

Dr. Guy P. CROWDEN found it impossible to

regard fatigue as a single entity ; he found himselfunable to isolate it from what appeared to be thedaily cycle of every active person. The problemto be faced was : is the phase of recovery a realand full compensation for the expenditure of energy ’?At the end of a day, and at the end of the week,fatigue had overtaken recovery and-speaking fromthe physiological standpoint-there was some leewayto be made up. Did the routine of life permit theday-to-day equilibration of that cycle 1 One couldnot assume a dominating influence preventingequilibration apart from many factors known toinfluence fatigue and recovery. In the case of theworker distinction must be made between dynamicfatigue as a result of movement efforts, and staticin which there was fixed attention with possiblestrain. There was too the factor of environment.Some work was done in comfort; ventilation,humidity, air movement, and radiant heat were

important, as well as distractions due to noise orvibration, not forgetting air pressure (caisson work).In all this it was impossible to ignore the personalfactor; much depended on whether the personconcerned was educated and able to appreciate thesignificance of changes in routine, the regulation oflight, and even the wearing of protective garments.Some single and apparently trivial factor mightturn out to be the chief cause. A person engaged ata desk might be at work which involved posturalstrain, and he might suffer considerable fatigue inlocal muscle groups. Fatigue meant a diminutionof capacity as assessed by the previous optimum ofphysical fitness. A further factor of real importancewas that of appropriate and sufficient food, linkedup with congenial home conditions.

Dr. R. K. HowAT argued that the process of

recovery from fatigue was never complete. It wastrue that after a period of rest one might feel asfresh as ever, but that did not mean complete recovery.Every living creature entered on life with a definitereserve of energy, and even with sufficient food and

periods of rest there was a danger of being on thewrong side in the matter of equilibration. Fatiguemight be a protective agency against completeexhaustion.

Dr. STEWART WEBB regarded fatigue as largelyindividual; many were content to perform the mostmonotonous tasks so long as they were not calledon to bear any responsibility.

Dr. H. L. ATTWATER spoke of the delicate andexacting work involved in making filament lamps,the suspension of the filament occupying about tenseconds each. Monotony was countered by theoffer of bonuses to those who dealt with the largestnumber of lamps each week, and there were nocomplaints of fatigue. On the other hand, thosewho had to produce dies for very fine work only putin short hours and did suffer from fatigue.

Mr. HOPE CARLTON agreed that fatigue was largelycentral, and the question of shock was important.A boxer who had been knocked out was sufferingfrom fatigue, and that was a central lesion. Dis-cipline also had much to say. During the late warthe endurance of a trained battalion as comparedwith that of new recruits was largely a question ofsuperior discipline. Recent work at Down Farmon fatigue in smooth muscle had disposed of oldideas on the subject ; there was no deficiency ofblood chlorides, even up to the point of death.

Fatigue was not due to histamine bodies ; the death-dealing substance lay in the cell.

Dr. LETITIA FAIRFIELD insisted on the importanceof rhythm, which became evident on watching themethods which workers chose for themselves.Children’s favourite method of doing things was toattack them in bursts of energy, alternated withperiods of rest, and if allowed to carry on as theypleased they were quite fresh at the end of a longday; whereas if a certain procedure was imposedon them they soon tired of the task. When a person’swhole desire and interest was concentrated on hiswork, this had the effect of postponing and diminish-ing the amount of fatigue. Men working at exactingoccupations for long hours during the late war wouldnot confess to fatigue although their muscles weretwitching and they were evidently spent. Absenceof mental conflict was very important.

Dr. ABRAHAMS in replying said it was usuallythe fussy person who was particular about theathlete’s diet ; the great athletes did not botherabout it. Also, the record-breaker was not usuallythe educated person ; if he were he would commenceto reason while at his running, and the first questionhe would ask would be, " Why am I doing it I Is itworth while "

LIVERPOOL MEDICAL INSTITUTION

A MEETING of this institution on Feb. 27th, withMr. G. C. E. SIMPSON, the president, in the chair,was devoted to short papers on problems in generalpractice.

Treatment of Psoriasis

Dr. R. M. B. MACKENNA said that certain definiteprecautions should be taken by persons prone to

psoriasis ; they should not wear tight clothing, theyshould avoid alcohol, foods containing spices, andfatty foods, and as a rule they should expose them-selves to sunlight as much as possible. With a severeattack in the stage of efflorescence, an expectantline of treatment should be adopted ; rest in bed wasa measure which was usually omitted but often didmore good than any other.

In the discussion which followed, Dr. F. GLYN-HUGHES, in reference to Dr. MacKenna’s mentionof German work supporting the idea of faulty fatmetabolism in psoriasis, said that until two monthsago it had been his practice in Belmont-road SkinHospital to put all his psoriasis patients on a fat-free diet. He was satisfied that this had decreasedthe time required to clear the skin. Lately he hadgone further and put these patients on a milk dietonly, and had been very pleased with the result,particularly in very chronic cases. The method hadthe advantage that it could be carried out at home.Speaking of the use of intramuscular injections ofmercury, he said he would like to be sure that theirgood results were due to the action of the drug onthe disease proper, and not to its action on syphilis,which could produce lesions closely resemblingthose of psoriasis. The Wassermann reaction inthese cases was not always reliable.

Dr. G. S. SwAN said that psoriasis was one of thebugbears of a general practitioner’s life. His mainobject was a form of treatment to enable the patientto continue his employment. Baths twice daily,followed by complete inunction, were almost impos-sible of achievement outside hospital.

Phlyctenular ConjunctivitisMr. A. McKiE REID, in a paper on the aetiology

and treatment of phlyctenular conjunctivitis, began