443THE IDEAL CLASSROOM.

be questioned any longer, for there is no more doubt asto the nature of these rays than of daylight. The

report from the Pathological Research Laboratory,under the direction of Dr. J. C. MOTTRAM, deals witha number of investigations of considerable interest.We may refer especially to the collaborate work withDr. W. CRAMER and Dr. A. H. DREW of the ImperialCancer Research Fund. The attempt is being made tocorrelate the similarities observed in animals whenthey are exposed to large doses of X rays or radiumand when deprived of B-vitamin. The mode of deathis strikingly similar under these different experi-mental conditions. Further investigations will beawaited with interest in view of the possible therapeuticindications which they may afford. The report of theChemico-Physical Laboratory under the direction ofMr. W. L. S. ALTOX, F.l.C., gives a brief summary ofthe various tubes and applications used during theyear, and deals in some detail with the various deviceswhich have been brought into operation for the safetyof the personnel. It is a difficult matter to protectthose handling radium from the penetrating gammarays, and it will be noticed in this report that protectionby distance is held in many cases to be more efficientthan that afforded by metallic screens. The report isof modest dimensions and should be read as a whole ;a copy of it will be sent post-free to any medicalpractitioner who applies to the Secretary of theInstitute, Riding House-street, London, W. 1.

THE SHEPHERD’S BUSH ORTHOPEDICHOSPITAL.

THE Military Orthopaedic Hospital at Shepherd’sBush has occupied for the past six years buildingsbelonging to the Hammersmith guardians, and pre-viously used by them as a general hospital for thepoor of the neighbourhood. Naturally the guardiansare now pressing for the restitution of their hospitalbeds, and the Minister of Pensions proposes totransfer the orthopaedic pensioners to the SouthAfrican Hutments Hospital at Richmond. Thegenerous equipment of apparatus provided at a cost-of £16,000 by the Red Cross would on this proposalnot accompany the in-patient pensioners, but remainavailable for the continued treatment of out-patientpensioners somewhere in the London area.. Theproposal is being strongly resisted by the presentstaff of the Orthopaedic Hospital, who see in it thebreak-up of one of the most successful pieces ofmedical team-work which the war produced, andmany questions have been asked in Parliament. Mr.Macpherson, for the Pensions Ministry, stated thatin his opinion the transference of staff and equipmentto Richmond would be in no way detrimental to thepatients, but, seeing that the time of the visiting staffis now fully occupied, while they will have six milesfurther to travel, they will obviously have less time todevote to their actual work, and medical opinion willhardly share the Minister’s comfortable view. More-over, from the segregation of in- and out-patienttreatment some duplication of apparatus must needsresult, inasmuch as in-patients at Richmond cannotbe allowed to suffer for the lack of facilities leftbehind at Hammersmith. We doubt whether theplea of economy will be found valid on further carefulinvestigation. But there is another point of greatimportance which should not be lost sight of. Aprocess of specialisation is gradually taking place inthe Poor-law hospitals of London, and it would seempeculiarly distressing to disband for a doubtful andmomentary gain what might form a permanent andaltogether admirable orthopaedic Poor-law unit. Wetrust that before the decision has become irrevocablethe Ministry of Pensions and the Ministry of Healthwill consult their common interest in this matter andtake the long view which combines efficiency witheconomy. ,

Annotations.THE IDEAL CLASSROOM.

" Ne quid nimis."

THE ventilation, lighting, and heating of classroomswere the subjects of discussion at a meeting ofthe Association of School Medical Officers held onFeb. 22nd, when Mr. G. H. Widdows, F.R.I.B.A.,asked for a considered medical opinion on somecontroversial points. Assuming, with Dr. LeonardHill, that in ventilation the primary need is a physicaland not a chemical one, Mr. Widdows asked how muchventilation is necessary ? It had been shown thatwith 10 sq. in. of hopper opening per child on oneside as inlet and a similar amount as outlet on theother side, and with a wind pressure of no more thanfour miles per hour, the air in a classroom could bechanged 10 times per hour by means of hoppers only.Was that sufficient ? As to lighting, could it be provedthat conflicting shadows, inevitable if the light camefrom more than one side, were harmful to the eyes ?Again, was the admission of sunlight into classroomsdesirable ? In the matter of heating, what was theideal system ? With open fires the children near thefire got too much heat, and those at the back of theroom did not get sufficient. High pressure hot waterhad its drawbacks by reason of the coils burning out.and by reason of the high temperature of the pipes.Mr. Widdows suggested that low pressure hot waterwould appear to be the most serviceable in ordinarybuildings. He drew attention to heating of theNorth Wingfield school by means of hot pipes undera concrete floor composed of floor slabs 2½ in. thickresting on a concrete grid. He dwelt on the economicaladvantage of thin walls in school buildings, providedthere were no hygienic drawbacks to their adoption,and praised the convenience of folding-tables to seattwo, four, or six children in place of the rigid slopingdesk.

If we may assume that Mr. Widdows was sincereand not merely complimentary in his expresseddesire for medical opinions on these points, he musthave suffered some measure of disappointment in theanimated discussion following his paper. For whilehis own professional colleagues, educationists andengineers, rose in quick succession, the last two speakersonly were members of the Association he had come toconsult. All expressed admiration for the beautifulschools built throughout Derbyshire to his plans, andmany openly envied the opportunities for experimentgranted to him by an enthusiastic county council.Mr. Gaster, of the Illuminating Engineering Society,asked what amount of illumination was desirable in aclassroom and what ill-effects were produced if it didnot reach the minimum standard required. Dr.E. H. T. Nash pleaded for a better place for the black-board than is usually accorded to it in a classroom,and pointed out that a reflecting wall painted asuitable colour is of more advantage than any attemptto borrow light from a neighbouring room or corridorby a glass partition. Dr. J. Kerr, who presided overthe latter part of the meeting, Mr. P. C. Elmsliehaving been called away, summed up the medicalaspect of some of the questions raised. He congratu-lated Mr. Widdows on having successfully and com-pletely separated the two problems of ventilation andheating which should always be kept distinct one fromthe other. The specific heat of air was so small thatit was expensive as well as undesirable to carry heatby air. The need of unilateral lighting depended onthe sizes of windows. If the light came from a largediffused surface without sharp shadows, its source

was less important. But if in a comparatively darkroom, where the eye was adapted for darkness, lightcame from two opposing sources, with conflictingshadows, strain and neurasthenia might result.

Similarly, streaks of sunlight were undesirable in aclassroom. Sloping desks Dr. Kerr regarded as

obsolete, being relics from the time when a rigid

444

posture was demanded of the school child. Manypoints raised by Mr. Widdows remained undiscussedfrom the medical aspect, but in view of their importanceit may be hoped that they will receive the earnestattention of those whose duty it is to interpret theresults of recent research to responsible authorities.

THE CLASSIFICATION OF BACTERIA.BACTERIOLOGISTS concerned with the examination

of water and milk have always felt the need ofsome form of classification which will differentiateorganisms of the B. coli group into those of humanand those of animal origin. Apart from the helpful workof W. M. Clark and other American workers on essen-tial differences of origin of organisms with differentcarbon dioxide to hydrogen ratio of gas production,little or no advance has been made in this directionduring the last two decades. It is easy enough toclassify by sugar-alcohol tests, but unless it can beshown that the groups so formed throw definite lighteither upon the functions or the sources of origin ofbacteria the classification is not of much use forpublic health purposes. In a recently publishedpaperl Mr. T. Redman, M.Sc., records the results ofpainstaking work in the classification of lactose-fermenting organisms of the B. coli group type. He hasisolated these micro-organisms from cheese, milk, andwater, and has endeavoured to group them along thelines of their cultural and agglutination characters.From the public health standpoint Redman’s laboriousefforts cannot be regarded as very helpful, for heclosely follows MacConkey’s method of classification,which has not been of demonstrable use. A con-siderable part of the paper is taken up with a studyof agglutination tests, a large number of strains beingused to prepare anti-sera. Here again these testsfail to give any clear-cut types, and although theauthor states that the strains differentiated intoMacConkey’s subgroups by cultural reactions are alsodifferentiated by their agglutinations, the tablesfurnished show that this is only true to a very limited’extent. We await with some anxiety the day whenan ingenious student of applied bacteriology willinvent a means of classification which will giveinformation of real practical value.

PACHYMENINGITIS HÆMORRHAGICA INTERNA.THE cause and nature of the pathological process

in pachymeningitis haemorrhagica interna, and therelation of this condition to traumatic subduralhaematoma. have always been subjects of much diversityof opinion, and nowhere in the text-books dealing withthem do we find any final conclusions expressed. At

present two hypotheses hold the field : the first thatthe lesion is primarily inflammatory-a true pachy-meningitis followed by repeated small secondaryhaemorrhages from the newly-formed blood-vessels ofthe organised exudate ; the second that haemorrhageis the essential factor and is followed by organisationof the clot.

In the current number of Tledical Science (1922, v.,496), Dr. F. M. R. Walshe discusses two important andrelatively recent papers in which both points of vieware represented. At the Seventeenth InternationalCongress of Medicine of 1913, held in London, Marie,Roussy, and Laroche discussed the morbid anatomyof pachymeningitis haemorrhagica interna. Theydescribed three main forms of lesion, with several sub-types. However, since in the great majority of theircases the diagnosis was made at autopsy, the conditionhaving been latent clinically, no information was

available as to the age of the lesion in any giveninstance. This clearly diminishes the value of theirobservations and conclusions, and we are left with theimpression that their classification is largely conven-tional and does not represent variations in a patho-logical process, but rather different stages in a more orless uniform process. In addition they carried outexperimental observations on animals by subduralinjections of blood, either sterile, infected, or mixed

1 Journal of Pathology and Bacteriology, 1922, xxv., 63.

with a chemical irritant. They failed to reproducetypical pachymeningitis haemorrhagica. This is notaltogether surprising for their experiments were acuteand completely neglected the essential time factor.However, they concluded that haemorrhage alone is notenough to account for pachymeningitis haemorrhagicain man and that a microbial or chemical irritation isessential, but without indicating how either arises. In1914 W. Trotter published in the British Journal ofSurgery what appears to be the most conclusive state-ment on the subject. He emphasises the importanceof the time factor in determining the symptomatologyof a nervous lesion. He points out that most progres-sive lesions produce their effects not by destruction oftissue but by interference with its blood-supply. Inhead injuries haemorrhage and oedema are the factorsleading to disturbances of cerebral function, and therate at which these processes impair the cerebral blood-supply determines the nature of functional disorderresulting. He contrasts rapid compression of the brainfrom traumatic extra-duraJ haemorrhage with thegradual compression occurring in subdural hsematoma.In the former case the haemorrhage is clinically latentuntil compression reduces the total venous capacityof the skull below that of its arterial blood. At this pointvenous engorgement results, with the appearance ofincreased excitability of nervous tissue and correspond-ing " irritative " symptoms-twitching of muscles,convulsions, delirium, and restlessness. Further com-pression produces capillary anaemia of the brain andparalysis of function in the affected part.In gradual compression, such as occurs in subdural

haematoma, a physiological compensation or tolerationensues, and hence no symptoms may be observed untila local anaemia is produced. Once the margin of tolera-tion is reached the patient passes suddenly into a stateindicating severe compression. Even normal variationsin intracranial tension may be sufficient to cause

startling symptoms to develop with great suddenness,and as rapidly to clear up. Trotter then compares thesymptomatology and morbid anatomy of traumaticsubdural hasmatoma and pachymeningitis haemor-rhagica and shows clearly that they are identical. Hebelieves that the source of haemorrhage is in the veinspassing from the cortex into the dural sinuses. Trivialblows on forehead or occiput may be sufficient to tearthese relatively unsupported vessels, from which inter-mittent oozing can go on for an indefinite period. Theperiphery of the blood mass clots and organises,leaving a fluid cyst into which further haemorrhagetakes place whenever venous pressure rises sufficientlyto overcome the resistance of the enclosing capsule.The absence of a history of head injury in many casesof pachymeningitis haemorrhagica is not a graveobjection to this point of view, for since trivial injuriesare most likely to be in question they are apt to beforgotten by the senile dements and alcoholics in whomthe condition is found, and who are especially prone toaccidents of the kind. Therefore Trotter concludesthat internal pachymeningitis haemorrhagica is a termwhich involves an unjustified hypothesis and shouldbe discarded in favour of some such term as chronicsubdural haemorrhage. Apart from certain cases

occurring in diseases which cause a strong tendencyto spontaneous haemorrhage, and possibly includingthem, hacmorrhagic pachymeningitis is a true traumatichaemorrhage coming from veins torn in their coursebetween brain and dural sinus. It should always bedealt with surgically. Finally, the variable and capri-cious course of such chronic haemorrhages, far fromrendering diagnosis exceptionally difficult, is capableof exact interpretation in accordance with the principlesof cerebral pathology, and constitutes a clinical typeat once well marked and characteristic. Marie, Roussy,and Laroche found that in almost all their cases thecondition was bilateral, and this also has been Trotter’sexperience, and he believes that surgical treatmentshould deal with both sides of the head simultaneously.The charm of Trotter’s lucid exposition is its strict

adherence to sound pathological principles. The trainof events he describes is eminently comprehensible andleaves less unexplained than any previous discussion of