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In a large injury, rigid fixing of the chest wall is veryundesirable, since it is likely to lead to pulmonary collapse inthe immobilised areas and is almost impossible to achieve.I cannot envisage an area so large as to require two limpetsleaving enough chest well to support the plaster, unless it

completely encircled the chest. Modern methods of manage-ment have been well documented,l and the problem now isnot one of effective treatment, but of making this treatmentavailable as widely as possible.

MICHAEL BOOKALLIL.Research Department of Anaesthetics,

Royal College of Surgeons,London, W.C.2.

REFLEX MEASUREMENTS IN THYROID DISEASE

GEORGE M. SIMPSON

JOHN H. BLAIR.Rockland State Hospital,Orangeburg, New York.

SiR,ŃThe article by Dr. Sherman and others (Feb. 2)details the usefulness of reflex measurements in thyroiddisease. We should like to point out, however, that

’ abnormal values can, on occasion, be present in otherconditions: in particular we refer to hypothyroid valuesin neurosyphilis, in a lobotomised schizophrenic, in

myasthenia gravis, 2 3 and in sarcoidosis.4 Differencesbetween the right and left leg have been described.3We mention this, not to detract from this valuable sign,

but to point out the possibility of the small number offalse positives being indicative of other pathologicalchanges.

SCHOOL REFUSAL

BERNARD BARNETT.

SiR,ŃThough merely descriptive and non-technical," school refusal " seems preferable to

" school phobia "for a "syndrome which can reflect a readily reversiblereaction, or which may be associated with severe neuroticor even psychotic disturbance ".5 This title highlightsthe common feature in that special dispensation has to beobtained for non-attendance at school, as well as hintingat the home tuition and psychiatric or legal actions thatmay ensue. Dr. Kahn’s first suggestion (April 13), how-ever, for this name covers only one group, since he himselfpoints out that the peak incidence is at 11 years. Many ofthe school refusals have in fact passed " the point fromlife predominantly in the family to life in the outsideworld " apparently successfully. Dr. Kahn later comesback to the central feature and elaborates that it occursat " crisis points ", and he further lists a number of

these, illuminatingly going well beyond the presentdiscussion of school adjustment.

Child psychiatry is increasingly taking account of the totalfamily and the social setting. In this instance further insightinto the problem might be obtained by viewing school refusalfrom the social aspect. Sociology has something to teach ushere. " Crisis points " or, more optimistically, " stepping-stones " are a feature in all societies, and individuals have atall times had difficulties in the role-changing periods hencethe rituals (often extreme) of the " rites of passage ". Con-temporary society with its ill-defined and often changing rolesand frequent changes of fashion has largely dispensed withrituals without in fact facing the underlying problems.

School refusal presents as an individual problem to thepsychiatrist, and the extraction of a psychopathology isessential in the elucidation of a particular personality and itsproblems for treatment, as Dr. Kahn emphasises. Yet it

might be helpful to consider school refusal as a social maladywell worthy of an epidemiological study.

Dr. Kahn’s list of individuals involved in the treatment1. Windsor, H. M., Dwyer, B. Thorax, 1961, 16, 3.2. Simpson, G. M., Blair, J. H., Nartowicz, G. R. New Engl. J. Med.

1963, 268, 89.3. Simpson, G. M., Blair, J. H., Nartowicz, G. R. N.Y. St. J. Med.

1963, 63, 1148.4. Richards, A. G. Canad. med. Ass. J. 1962, 86, 32.5. Rodriguez, A., Rodriguez, M., Eisenberg, L. Amer. J. Psychiat. 1959,

116, 540 (quoted by Cameron in Medical Annual, 1961).

indicates the sort of liaison which is needed and which prob-ably exists in few parts of the country. Contact between themmust be fostered to avoid the complication of transferral afterfailure by an earlier agency, as well as to help identify thevulnerable individuals who need special attention at crisis

periods.As a first step and a baseline for further study and evalua-

tion of treatments, it might be fruitful for all disciplines con-cerned to undertake, possibly under the aegis of the Ministryof Education, a national survey. Unlike many psychiatricconditions the actual incidence and case ascertainment can beestablished. It is no less of a problem for the educationauthorities than for the psychiatric clinics, where it has beensuggested that it is on the increase and already forms 5% ofreferrals. R

Birmingham. BERNARD BARNETT.

VENTILATION OF OPERATING-ROOM SUITES

C. G. TROTMAN.

Sir should like to comment on the letter from Dr.Blowers and others (Jan. 19) supporting the recommenda-tion made by the operating-theatre hygiene committeethat filtration of input air down to 5 microns isbacteriologically adequate.

It is known that filters which are 99% efficient against therelatively large test dust particles down to 5 microns in diameter(Test Dust no. 2 B.s.2831) will allow to pass at least 50% of theparticles normally occurring as atmospheric pollution. Whilstmost airborne microorganisms may tend to be carried by thelarger pollution particles and will thus be removed by a5-micron filter, a significant proportion of them will pass thefilter on fine dust particles (Dr. Blowers found 2%) and enterthe theatre. This surely is undesirable and should be avoided.But I suggest that a low, or even zero, bacteriological count

in the incoming air is not the sole criterion on which to basea standard for efficiency, since it takes no account of the verylarge numbers of sterile airborne dust particles which will passa 5-micron filter and enter the theatre. Most of these particleswill, or should, pass out of the theatre by ventilation, but manywill be deposited and will aggregate on vertical and horizontalsurfaces and will become potential hosts for the microorganismswhich are, at present, unavoidably brought into the theatre—for example, by the operating staff—and which cannot beremoved with absolute certainty by ventilation.

Since, as stated in the letter by Mr. Sutherland andMr. Firman,7 the cost of filters of very high efficiency islow compared with the cost of infection of even one patient,the case for using filters of the highest possible efficiencyseems irrefutable.

Salisbury, Wilts. C. G. TROTMAN.

HYPONATRÆMIA IN INFANTILEMALNUTRITION

SIR,-Since Dr. Smith’s excellent work while he wasin this unit, we have been aware of the danger of pul-monary oedema in malnourished infants, referred to inhis letter of April 6. The unit’s views are expressed in arecent review of treatment and prognosis in malnutri-tion : " The most dangerous pitfall is to infuse too muchfluid into a wasted child." 1

Of the last 13 children who died, only 1 had severe pul-monary oedema, while 5 more had minimal fluid in the lowerlobes at postmortem. 9 of these children were admitted withsigns of failure of hepatic function (i.e., bilirubin above 1 mg.per 100 ml. or serum glutamic-pyruvic transaminase over250 V.. per 0.1 ml.), and of these, 5 had serum-sodium levelsof 125 mEq. per litre or less.The question now is not " Do the babies die of hypona-

træmia or of hyperbilirubinæmia ? " but " What cell functions6. Coulsting, H. Brit. J. Psychiat. 1961, 107, R.M.P.A. supplement

(April), p. 25.7. Lancet, 1962, ii, 1169.8. Garrow, J. S., Picou, D., Waterlow, J. C. W. Indian med. J. 1962,

11, 217.

1003

are altered ? " to account for the change of serum and intra-cellular composition.

A. E. M. MCLEAN.

M.R.C. TropicalMetabolism Research Unit,

University College ofthe West Indies,Mona, St. Andrew,

Jamaica.

EFFECTS OF DIAGNOSTIC IRRADIATION

DAVID W. LINDSAY.Royal Infirmary,Edinburgh.

SIR, The correspondence 1-4 since your leader 5 hasresulted in dropping the " Harmful " from the " Effectsof Diagnostic Irradiation ". No-one has contributed tothis more than Dr. Alice Stewart, whose detailed studieshave shown that the bulk of leukxmias cannot possiblybe due to diagnostic radiology and that with the remainderit is only a possibility.There remains the genetic effect of radiation to cause

anxiety in those requiring X-rays. The full genetic con-sequence of X rays will not be manifested for thousandsif not millions of years. It is therefore important tohave a clear realisation of what these consequenceswill be.The effects of gene mutation can nowhere be better learnt

than by studying the principal display in the main hall of theBritish Museum (Natural History), South Kensington, Lon-don. Here we learn " any given gene mutates in about onein half a million individuals ". s

Radiation, however, is not the only cause of gene mutation.Background radiation, " the total is roughly O-lr per annumor about 3 per generation ",’ causes less than one-tenth of thenumber of naturally occurring gene mutations which require"between 30r and 80r". 8 Background radiation thereforecauses any given gene to mutate in about 1 in 5,000,000individuals.

Diagnostic radiology amounts to only 14% of backgroundradiation. The chance of diagnostic radiology causing a geneto mutate is therefore 1 in 35,000,000. If the birth-rate inGreat Britain remains around 700,000 births per year, theprobability that 1 baby will be born with such a mutation dueto diagnostic radiology is once in fifty years.One baby in Great Britain each fifty years is, however, the

effect on one gene only. As there are many genes the effectmust be multiplied many times. No matter how much wemultiply, however, the contribution of diagnostic radiologywill not exceed 14% of the contribution of naturally occurringbackground radiation, or about 1 % of all gene mutations.

It is known that the Atomic Bomb Casualty Commission" has found no evidence of genetic damage in the offspring ofJapanese parents exposed to atomic radiation, even amongthose heavily irradiated ", and 1 mutated baby per gene every50 years may not be considered very many, but can one tellwhat effect this will have if we are sufficiently lavish withtime? Fortunately nature has made a grand experiment forus which gives us the answer. In different parts of GreatBritain background radiation differs by 20%.10 In differentparts of the world background radiation differs by 400%. Thisdifference has been present since before life began withoutany detected detrimental influence to the population." Thepossibility of the 14% contribution of diagnostic radiologyhaving an effect which may be called harmful is thereforemost unlikely.

1. Burch, P. R. J. Lancet, Feb. 23, 1963, p. 441.2. Lindsay, D. W. ibid. March 16, 1963, p. 602.3. Rabinowitch, J. ibid. p. 603.4. Stewart, A. ibid. March 30, 1963, p. 718.5. Lancet, Feb. 2, 1963, p. 255.6. British Museum (Natural History), London. Evolution; p. 15.7. Hazard to Man of Nuclear and Allied Radiations; p. 45. H.M.

Stationery Office, 1956.8. ibid. p. 50.9. Radiological Hazards to Patients; p. 84. H.M. Stationery Office, 1960.10. Ross, S. E. J. Amer. med. Ass. 1963, 183, 721.11. Brit. med. J. 1962, ii, 716.

SPINAL-CORD DAMAGE FROM HYPEREXTENSION

INJURIES IN CERVICAL SPONDYLOSIS

J. B. COOK.Department of Neurology,

Pinderfields General Hospital,Wakefield.

SiR,—The association of cervical injury with ruptureof the intervertebral disc was described 100 years ago, 1and that this is a common cause of spinal-cord damage inextension injury of the neck is well established. 2-6

Although it is true that this sort of injury is most oftenseen in the middle-aged and elderly, it is by no meansexclusive to them, and it is found in young people whohave had similar accidents.The spinal cord is at greater risk in the elderly, particularly

in neck extension, because cervical spondylosis which narrowsthe spinal canal is more common in them. This has been des-cribed in many papers.5 7-11 Extension injuries are commonerin older people, because the elderly tumble more frequently,and it is doubtful if any of the three patients described byDr. Hughes and Dr. Brownell (March 30) would have sustainedtheir injury had they not been elderly and liable to fall.An injury to the neck in flexion must be forceful to cause

spinal cord damage.2 12 In the nature of things young peopletend to be involved in violent accidents, but they also maysustain severe cord damage due to extension of the neck inaccidents of apparently trivial violence.7 13 14

Cervical spondylosis is only one element in the causationof cord damage from extension of the neck. The cord inthe hyperextended neck is vulnerable at any age, and it isfailure to realise this and that bony change may be absentor, if present, slight that leads to the misdiagnosis andmismanagement of traumatic tetraplegia, and that causedme to state 1-4 " the facility with which severe cervical-cordtrauma may be sustained is only surpassed by the easewith which such damase can be overlooked ".

EFFECT OF THALIDOMIDEON SKIN-GRAFT SURVIVAL

SiR,—Two recent communications15 16 have pointed outthe similarity of action of tuberculin and of phytohæmag-glutinin (P.H.A.) on cultures of human lymphocytes ininducing mitosis and transformation to large basophiliccells, and hinted at a parallel with the cellular immuneresponse in vivo. Among the substances that have beenshown to inhibit the transformation caused by P.H.A. areprednisolone17 and thalidomide, 18 both of which producesome effect in concentrations comparable to those in theblood after an ordinary therapeutic dose. Since predni-solone is also known to delay the rejection of skin homo-grafts and suppress the formation of large basophilic andpyroninophilic cells in the regional lymph-nodes,19 it wasthought worth while to test thalidomide for this property.

Fifteen adult CBA female mice were given thalidomide40 mg. daily (2000 mg. per kg.) orally in arachis oil for 35 days.1. Butcher, R. G. H. Dublin J. med. Sci. 1853, 15, 383.2. Barnes, R. J. Bone Jt Surg. 1948, 30B, 234.3. Taylor, A. R., Blackwood, W. ibid. p. 245.4. Kaplan, C. J. ibid. 1953, 35B, 97.5. Birkin, C. R., Hirson, C. ibid. 1954, 36B, 57.6. Cook, J. B. Proc. R. Soc. Med. 1959, 52, 799.7. Symonds, C. Lancet, 1953, i, 451.8. Crooks, F., Birkett, A. M. Brit. J. Surg. 1943, 31, 252.9. Alexander, E., Davis, C. H., Field, C. H. Arch. Neurol. Psychiat.

1958, 79, 146.10. Payne, E. E., Spillane, J. D. Brain, 1957, 80, 571.11. Taylor, A. R. J. Bone Jt Surg. 1951, 33B, 543.12. Jefferson, G. Brit. med. J. 1936, ii, 1126.13. Wilson, P. D., Cochrane, W. A. Fractures and Dislocations. London,

1925.14. Cook, J. B. in Scientific Aspects of Neurology (edited by H. G. Garland);

p. 764. London, 1961.15. Pearmain, G., Lycette, R. R., Fitzgerald, P. H. Lancet, March 23, 1963,

p. 637.16. Marshall, W. H., Roberts, K. B. ibid. April 6, 1963, p. 773.17. Nowell, P. C. Cancer Res. 1961, 21, 1518.18. Roath, S., Elves, M. W., Israels, M. C. G. Lancet, Feb. 2, 1963, p. 249.19. Scothorne, R. J. Ann. N.Y. Acad. Sci. 1957, 64, 1028.