810

able and normal life than one with only two or three ?It is reasonable to think that he should ; and, althoughthere is no statistical evidence to support this, clinicalimpressions suggest that he does. The radical treat-ment of lung cancer advocated by BROCK andWHYTEHEAD cannot yet be accepted as the besttreatment.

Annotations

TONSILLECTOMY AND RESPIRATORY INFECTIONS

THE indications for tonsillectomy may seem to bebased more on intuition than on reason. Evaluation ofthe results, by differing methods of assessment,1-4 hasalready cast serious doubt on the value of the opera-tion. Among the lexicon-like list of reasons for under-taking it, repeated respiratory infections (and- whatchild does not have them ?) has been well to the fore.Now McCorkle et al.5 have made a painstaking assess-ment of the relation of tonsillectomy to the incidenceof such infections. This study can be faulted at only onepoint-the small numbers concerned. But the 230children studied were observed for up to five years,during which the mothers kept a daily health record,field workers paid a weekly visit, and physicians assessedall illnesses with the help of extensive bacteriologicalinvestigations.The results are presented under two headings. Under

the first heading " the age-specific rate of infection "of two groups of children-tonsillectomised and not,before the period of observation began-is compared.Under the second heading is shown " the age-adjustedrate of infection " in a group of 26 children who, becausethey had a higher than expected rate of infection, wereoperated on during the period of observation. McCorkleet al. state : " Comparison of these data requires theuse of either age-specific or age-adjusted rates becausethe incidence of common respiratory illness changeswith age, and post-tonsillectomy experience is heavilyweighted with older children." The outcome of this studywas that the operation had no effect at all; and the26 children with a higher than expected rate of infectioncontinued unchanged at the higher rate after the

operation.The great care with which this study was conducted

suggests that, though the numbers were small, theresults would be the same whatever the total.

WEIGHT-GAIN IN INFANCY

THE importance of recording reliable anthropometricdata in childhood is only now being fully recognised.6During and since the late war valuable contributionshave been made by H. C. Stuart, A. H. Washburn, N. C.Wetzel..and others in the U.S.A., by workers at theInstitute of Child Health, University of London, directedby A. A. Moncrien, and by J. M. Tanner and R. W. B.Ellis.Thomson has studied the weight-gain during the first

year of life of infants at a child-welfare clinic in Edin-burgh. The observations were made monthly on legiti-mate, singleton, first-pregnancy infants whose birth-weights were within the range of over 51/2 to 91/2 lb. ;1737 observations were made on males and 1605 onfemales. Thomson confirmed that throughout the firstyear the mean weight-gain of the male is greater than1. Kaiser, A. D. J. Amer. med. Ass. 1930, 95, 837.2. Spec. Rep. Ser. med. Res. Coun., Lond. 1938, no. 227.3. Paton, J. H. P. Quart. J. Med. 1943, 12, 119.4. Walker, J. S. Arch. Otolaryng., Chicago, 1953, 57, 664.5. McCorkle, L. P.. Hodges, R. G., Badger, G. F., Dingle, J. H.

Jordan, W. S. New Engl. J. Med. 1955, 252, 1066.6. Tanner, J. M. Arch. Dis. Childh. 1952, 27, 10.7. Thomson, J. Ibid, 1955, 30, 322.

that of the female ; for instance, the mean weight-gainin the male at 26 weeks was not attained until 3 weekslater by the female, and the weight attained by thefemale at 1 year was reached by the male 8 weeks earlier.Thus there is ample justification for recording and

assessing the weight pattern separately according to sex.Despite this differing pattern, Thomson found that theproportion of the total weight-gain in the first year atparticular ages was the same in the two sexes ; for

instance, in both sexes a quarter of the total weight-gainwas attained at 10 weeks, half at 20 weeks, and three-quarters at 32 weeks. This study strongly suggests thatin singleton infants born at term birth-weight is unrelatedto the rate of postnatal weight-gain. Accordingly in

assessing progress the rate of weight-gain is much moreimportant than the actual weight-a fact appreciated byexperienced clinicians. Comparison with the careful

recordings of Finlay 11 in Edinburgh thirty years agoshowed that the mean weight at 1 year is now 30 oz.greater. This is probably a fair reflection of the improve-ment in development and health in infancy throughoutthe country during this period of rising economic andnutritive standards. Thomson rightly emphasises thatthe standard graph weight-cards used in most local-

authority clinics are out of date, and should be revised toprovide norms which accurately reflect the improveddevelopment of infants nowadays.

Parents who show an interest in the weight of theirinfants should be told that standard weight-for-agecharts are based on the average weights of many infants ;otherwise they tend to be alarmed by weights that arenot close to the average but which may be quite normalfor their infant. If their infant is to be weighed at all itshould be weighed methodically and accurately, as atmost child-welfare clinics ; and the influence of factorssuch as race, heredity, and prematurity on the actualweight should always be borne in mind. Provided a babylooks healthy and seems to be making good progress itis a mistake to focus attention on weight-gain, sincenormal irregularities in the rate of gain are often mis-understood by parents and cause them much unnecessaryworry. Routine weekly weighing is desirable in the firstmonth or two of life ; but thereafter it should be done atlengthening intervals, provided the general progress is

satisfactory, and between the ages of 6 months and 1

year 2-monthly weighing suffices.

THE LUNGS IN EMPHYSEMA

surface of the lungs is lower than that at the mouth,surface of the lungs is lower than that at the mouth,because of the elastic pull of the lungs. To produceinspiration/the pressure at the surface of the lungs hasto be lowered still further and the fall which takes placeis a measure of the force required. This force has toovercome two mechanical factors : the elastic pull ofthe lungs, which increases as the lung is distended, andthe resistance to airflow when air moves through therespiratory passages. When expiration takes place thesefactors are again in operation. In order to analyse themechanics of respiration it is necessary to separate theeffects of airflow resistance from those of the elastictension of the lungs, and, although technically difficult,this can be done graphically or, as Mead et awl. now

report, by plotting the variables with a cathode-rayoscilloscope.

Mea-d et al. examined the mechanical properties of thelungs in 10 healthy people and in 10 patients withemphysema. They found that during quiet breathingpulmonary flow resistance was greater in the patientsthan in the healthy people throughout the respiratorycycle, but especially during expiration when it was

8. Finlay, T. Y. Edinb. med. J. 1924, 31, 317.9. Mead, J., Lindgren, I., Gaensler, E. A. J. clin. Invest. 1955,

34, 1005.

811

about - 30 times as great. Moreover, in the patients theflow resistance during expiration was greater than duringinspiration, whereas in the controls this was not so.

When the subjects hyperventilated the pattern changed.In patients and controls the flow resistance during rapidinspiration was approximately the same as it was duringquiet breathing ; but during rapid expiration the flowresistance in both patients and controls greatly increased,though the peak flow resistance in the patients was about10 times as great as in the controls. - The finding that inhealthy people expiratory flow resistance is greater thaninspiratory resistance during hyperventilation, but notduring quiet breathing, is not unexpected. During quietbreathing, even in expiration, the pressure on the outsideof the respiratory airways-certainly the extrapulmonaryones—more closely approximates to the still-negativeintrapleural pressure than to the pressure within theairways, and the difference tends to keep the tubesexpanded. But during rapid forced expiration this

pressure difference is reversed and the calibre of the

airways is reduced, thus increasing the pulmonary flowresistance. Conversely, during inspiration the pressureon the outside of the airways falls and tends to increasetheir calibre. Bronchoscopists can vouch for the pro-nounced narrowing of the larger bronchi during forcedexpiration. Mead et awl. cite several structural changesthat might result in the abnormal compression of theairways which their findings suggest occurs in emphy-sema : reduction in cross-section of the smaller airways,increased tissue frictional resistance, weakening of thestructure of the bronchial walls, and a tendency for theairways to collapse due to reduction of lung elasticity.10As regards lung elasticity, Mead et al. found that under

" static " conditions the lungs of emphysematous patientswere more distensible than normal: that is, if the

subjects took a slow maximal inspiration and kept theirglottis open, it was found that for a unit fall in pressureat the surface of the lungs a bigger volume of air enteredthe lungs of an emphysematous patient than entered thelungs of a healthy person. They also confirmed anobservation, first made by Christie, 1112 that in emphysema-tous patients, unlike normal subjects, the lungs apparentlybecome less distensible as the rate of breathing increases.Experimentally they threw some light on this phenome-non. First they measured the distensibility of a dog’slungs and then completely blocked the left main bronchuswith a balloon. They found that the distensibility of thelungs was almost halved, because when a given volume ofair was inspired the right lung had to be distended toaccommodate all of it instead of accommodating a littleover half as it would have done had the left lung beenworking normally. Next they deflated the balloon sothat the left main bronchus was only partly blocked.During quiet breathing air went in and out of the leftlung almost as it did when the left main bronchus wasclear, and the distensibility of the lungs was normal.But when the rate of respiration was increased the picturealtered-the faster the breathing the less the volume ofair which went in and out of the left lung, until at veryrapid rates almost all the air went in and out of the rightlung and the volume of the left lung scarcely changed.Also, the distensibility of the lungs decreased as the rateof breathing increased until at very rapid rates the

distensibility of the lungs fell to what it had been whenthe left main bronchus was completely obstructed by theballoon. At slow rates of breathing, therefore, the increasein flow resistance produced by partial obstruction of theleft main bronchus was negligible, but at rapid rates therewas virtually complete functional block of the bronchus.

If it is supposed that in emphysema there are numerouspartly obstructed respiratory channels this mechanism10. Fry, D. L., Ebert, R. V., Stead, W. W., Brown, C. C. Amer. J.

Med. 1954, 16, 80.11. Christie, R. V. J. clin. Invest. 1934, 13, 295.12. McIlroy, M. B., Christie, R. V. Thorax, 1952, 7, 291.

could explain why the lungs apparently become lessdistensible as the rate of breathing increases : at slowrates air will move with little difficulty in and out of theaffected areas of lung, but at rapid rates it will tend toavoid them and be accommodated in normal neigh-bouring parts of the lung. In effect, therefore, at highrates of breathing the more normal parts of the lungs willhave to be distended to accommodate air which at lowerrates would be received in partly obstructed areas, andthus the distensibility of the lungs will apparentlydecrease. Mead et al. also point out that this mechanismcould explain the development of emphysema in cases ofbronchial asthma and chronic bronchitis. During thedeep, rapid inspiration which follows coughing little airwill enter partly obstructed areas of lung, and the con-sequent overdistension of neighbouring normal areas willbe likely to lead eventually to structural damage. Thisis certainly. an interesting hypothesis.

THE ANAL SPHINCTERS

THE anatomy of the anal canal provides a salutaryreminder of the imperfection of our powers of observation.Thompson’s 1 classic description of the anal sphincterwas neglected for over thirty years until it was utilisedclinically by Milligan and Morgan 2 ; but even thenanatomical textbooks continued to take no account of it.

Thompson found that the external sphincter consisted ofthree parts : a subcutaneous part, a superficial part whichlay deeper, and above this the deep external sphincter.Milligan and Morgan regarded the subcutaneous partas separate from its two fellows ; it was unattached to

perineal body in front or to coccyx behind. Was it notthis loose " umbrella ring " that was seen in the fioorof a chronic fissure, and its contraction, due to spasm andfibrosis, the reason for the persistence of the fissure ?The argument was carried a stage further by the sug-gestion - that spasm of the muscle brought about thecondition, with models in Plasticine’ to prove the

poimt.3 " The subcutaneous sphincter ani externus isthe structural cause of fissure-in-ano.... Division of thesubcutaneous external sphincter ani and enlargement ofthe skin wound is the radical cure. We may now fairlyclaim to know both the cause and cure of fissure." 4 Ball’s 5

hypothesis that fissure was due to the tearing down of ananal valve had proved unsatisfactory since many a

fissure did not extend to that level ; besides the treat-ment suggested by the St. Mark’s Hospital group 4 curedthe condition. Meanwhile the internal sphincter wiltedunder neglect. But doubt remained in some minds 6 ;for why should the muscle, seen in dissection undertakenfor fissure and termed external sphincter, appear so

pale-too pale, it would seem, for somatic origin Nowwe have the answer from St. Mark’s Hospital itself. Byplacing thread sutures, before the patient was anæsthe-tised, through the lower borders of external and internalsphincters identified by palpation, Goligher et al. haveshown that with relaxation due to anaesthesia the external

sphincter retracts laterally and the muscle seen in thebase of a fissure is indeed the lower end of the internal

sphincter-an observation confirmed by biopsy revealingsmooth muscle. They have further demonstrated thatthis part of the internal muscle is divided into discreteelliptical bundles ; this accounts for the view 2 that thelower part of the " external " sphincter was a separateentity without attachments. The division of the external

sphincter into three parts must be regarded as an

anatomical observation resulting from the dissection of1. Thompson, P. Myology of the Pelvic Floor. London, 1899.2. Milligan, E. T. C., Morgan, C. N., Jones, L. E., Officer, R. Lancet,

1937, ii, 1119.3. Gabriel, W. B. Principles and Practice of Rectal Surgery.

London, 1945 ; p. 130.4. Milligan, E. T. C. Proc. R. Soc. Med. 1943, 36, 365.5. Ball, C. The Rectum. London, 1910.6. Eisenhammer, S. S. Afr. med. J. 1953, 27, 266.7. Goligher, J. C., Leacock, A. G., Brossy, J. J. Brit. J. Surg.

1955, 43, 51.