FETAL CEPHALOMETRY

177 of unnecessary death. It would be interesting to have some thought from the Medical Service of the National Coal Board on the thesis put forward above. 2 The

Grove, Marton,

Middlesbrough.

J. T. B. BAIN.

SYSTEMIC HYPERTENSION AFTER HOMOGRAFT AORTIC VALVAR REPLACEMENT SiR,—The remarks of Dr Stewart (Jan. 12, p. 65) on our paper (Dec. 15, p. 1343) reflect some of the difficulties inherent in a retrospective study of clinical material. He concludes " that the evidence for any connection between aortic valvar replacement and the development of systemic hypertension is insufficient ". We should like to comment on some of the additional assumptions he made in reanalys-

ing our data. The 14 patients who had preoperative hypertension were considered to have " developed " systemic hypertension postoperatively, in the sense that 17 additional patients with preoperative hypertension became and remained normotensive after surgery.

Also the reappearance of

hypertension postoperatively was often delayed; in 5 patients it returned more than three years after surgery. It is not the case " that a considerable number of the 14 who had been hypertensive preoperatively were among those who developed the highest pressures ". In this group the mean diastolic pressure was 108 mm. Hg (S.E.M. 2’1 mm. Hg), while in the 25 patients with raised bloodpressure first found after surgery the mean was 110 mm. Hg (S.E.M. 2-8 mm. Hg). Our results do not explain the association between homograft aortic-valve replacement and systemic hypertension, but, like Dr Stewart, we do not think that it is due to the specific type of surgery. CLIVE A. LAYTON WALLACE BRIGDEN ALASTAIR MCDONALD London Hospital, JOHN WEAVER. Whitechapel, E1 1BE

fostered by means of modern advertising and salesmanship, will become less prominent." Well, it made a bad start: from the first 1974 issue of The Lancet, the one in which Dr Loraine’s article appeared, the one whose first leader was on obesity (in the West), there dropped a multicoloured postcard inviting me and my car to take a holiday in Europe. And since Christmas our newspapers, as well as providing news of our various crises-in oil, newsprint, been providing whole supplements on the &c.-have of pleasures going by jet plane to this or that part of the world for our 1974 holidays. We are even invited to go to some of the poor and hungry countries of the world which, when the advertising is for tourists and not for charity, become " picturesque, romantic, away-from-it-all ", and seemingly free from starving or leprotic children. Population increase in the underdeveloped world is largely a product of the unthinking intervention of Western technological medicine (an almost exact replica of the 19th century intervention of Western religion); and yet our only answer to it is a further intervention-with the pill, I.U.D.S, more vasectomies, more abortions-though our own population, even with such aids, is only now approaching zero growth. If Washington, D.C., can have, as it now does, two abortions to every one live birth, why not Lima ? It seems never to occur to Western scientists that there could be a wisdom greater than that of science; that, before our intervention, the " primitive " countriesdisease, hardship, a total absence of tourism, and all-were on the whole happier and more viable than today; and to draw conclusions. As for the World Population Conference to be held in Bucharest in August, if previous similar conferences are anything to go by, its main effect will be an increase in the per-caput consumption of food and drink in Bucharest in August. As regards world overpopulation we are whistling in the dark. It is a darkness we sick Westerners have made, though whether it is a darkness any man can dispel is another matter. Garraway House, How Caple, Hereford.

S. BRADSHAW.

FETAL CEPHALOMETRY

POPULATION YEAR SiR,—In his article on world population Dr Loraine (Jan. 5, p. 22) expresses a qualified optimism, yet the last two F.A.O. reports indicate that, despite all the talk about the green revolution, food production in the underdeveloped world is falling further and further behind the population increase. Moreover, as Lord Rothschild has indicated

(Times, Jan. 9, p. 14), Western technological farming is highly energy-intensive, and its energy " output/input " ratio is falling. Dr Loraine suggests the developed world should give some of its wealth for the poor countries of the world. So that, as we and France have just demonstrated in relation to the Middle East, they may spend it on armaments and

up

Western-style technological development-thus ensuring that any drop in their rate of population increase will be matched by an increase in that per-caput consumption of

irreplaceable natural resources the size of which Dr Loraine rightly deplores in ourselves ? He says, too, that in 1973 people began to accept the ecologists’ case against unfettered economic growth; and I agree that they didI know of as a topic for conversation over the canapes. in the world who has been elected on the basis of a policy for a reduction in the rate of his country’s -never mind the world’s-economic growth, leave aside Can Dr Loraine name one ? a reduction of it to zero. " During 1974", he says, " the materialistic ethos, no statesman

SIR,-Correspondence 1,2 on this subject prompts me to offer the following comments. Newcastle is one of the many " centres which in recent years have adopted the Campbell technique ", which is no more than a basic principle. It is very much more difficult to perform in practice. The " measurement " of a fetal biparietal diameter (B.p.D.) requires positive identification of the correct dimension -i.e., one of the infinite number of planes which pass through the parietal eminences. Davison et al. revealed that they did not know when they had achieved this condition. It is hardly surprising, therefore, that their trial should show results of limited usefulness. It is difficult to understand why they should claim to have had two years’ experience of the technique before beginning their trial, because the actual time was nearer one year. Thus it is, in my opinion, a little premature for them to judge their performance, since this will doubtless improve with time and the recent acquisition of more experienced personnel. I would also disagree with their supposition that cephalometry should take up to twenty minutes per patient. After six years and the experience of more than 15,000 examinations, the personnel of my department now use an improved technique which rarely lasts more than six minutes per patient, during which time nine standard measurements are made. Details of this technique will be published Whether or not these measurements give the shortly. true B.P.D. is irrelevant to the assessment of maturity and growth. It is not altogether certain from the correspondence that Davison and his colleagues appreciate this point.

178

Campbell1 seems to have taken the article of Davison al. a little personally, but their objective was, surely, to point out that new operators with little experience should not expect such precise results as those obtainable by et

Talking Politics

r’#"j.......,,_k.o.l1 n.....A 1-,,;C’O

Diagnostic Ultrasound Department, Royal Infirmary, Dundee DD1 9ND.

A DUTY TO HOUSE

A. D. CHRISTIE.

Campbell, S. Lancet, 1973, ii, 1145. Davison, J. M., Lind, T., Farr, V., Whittingham, T. A. ibid. p. 1329 Davison, J. M., Lind, T., Farr, V., Whittingham, T. A. J. Obstet Gynœc. Br. Commonw. 1973, 80, 769.

1. 2. 3.

POLYMYALGIA RHEUMATICA AND LIVER DISEASE

SIR,-The paper by Dr Long and Dr James (Jan. 19, 77) draws attention to this association. I have used the

p.

serum-alkaline-phosphatase test in the routine screening of over a hundred patients with polymyalgia rheumatica and I have not seen elevated figures. Although the diagnosis of polymyalgia rheumatica is often described as classical " there are, in fact, no agreed criteria, and it is clear from published reports of the frequency of associated phenomena -for example, synovitis-that the criteria of various observers differ considerably. My observations suggest "

that liver disease must be rather a rare association of polymyalgia rheumatica. Perhaps the moral to be drawn is that diagnostic criteria analogous to those put forward by the American Rheumatism Association for rheumatoid arthritis, or the Duckett-Jones criteria for rheumatic fever, should be designed for polymyalgia rheumatica. Such criteria would not be exclusive, but at least they would be reproducible between observers in studies of the treatment of the disease or complications of polymyalgia rheumatica. Royal National Hospital for Rheumatic Diseases, Bath BA1 1RL.

A. ST. J. DIXON.

NEURAL-TUBE DEFECTS AND TWINNING

SIR,-In suggesting that dizygotic twinning and anencephaly may be associated, Dr Elwood (Jan. 5, p. 31) mention Knox’s " fetus/fetus interaction " which not only envisages such an association but suggests how it might arise. The hypothesis is that single-born children with neural-tube defects are the survivors of pairs of dizygotic twin embryos who did not share certain gene-based recognition characters (one or more of them sex-linked). In the presence of certain environmental factors, it is envisaged that such twins might interact so that one would be eliminated and the other sustain a neural-tube defect. This concept was originally put forward merely as a model that fitted the low sex ratios for these defects and most of the findings in family studies, but there are now two further lines of evidence which seem to point the same way. One of these pointers is mentioned by Dr Elwoodthe reports of anencephalic births to mothers who had taken clomiphene, which can cause multiple ovulations. The other new evidence is the fulfilment by recent British data 2,3 of a prediction by Knox that, if his hypothesis were correct, the preponderance of females among anencephalics would tend to be greater during periods when prevalence at birth was relatively high than at other times.

omits

to

hypothesis,1

University Department of Community Medicine, York Place, Manchester M13 0JJ. 1. 2. 3.

IAN LECK.

Knox, E. G. Devl Med. Chld Neurol. 1970, 12, 167. Leck, I. Teratology, 1972, 5, 303. Rogers, S. C., Morris, M. Br. J. prev. soc. Med. 1973, 27, 81.

NONE of the statistics is really reliable, but M.p.s from the big cities generally fear that the problems of urban homelessness are getting worse. Given the stagnant state of the housing programme, the disappearance of cheap lodging houses, the sale of institutions like the old Rowton Houses to earn more profit as hotels, that’s scarcely surprising. So urban M.p.s were not pleased when the Local Government Bill last year abruptly removed certain duties placed on local authorities by an Act of 1948 to look after homeless people, and replaced them simply by powers to carry out these functions. To a good local authority, it was argued, this would make very little difference: but to a bad one, wouldn’t it provide a good excuse for backsliding ? Mr Jock Stallard is Labour M.p. for St. Pancras, which, as an area well populated with railway terminals, knows more about homeless people than most. Brooding on these matters over Christmas, he resolved to put down an amendment to this year’s Local Government Bill, reimposing a duty on local authorities to provide temporary accommodation for those in urgent need, which was defined as " need arising in circumstances which could not reasonably have been foreseen " or other circumstances such as the consequences of fire, flood, and eviction. Several other inner-city Labour n2.r.s at the thick of the housing battle quickly added their names to the amendment: but so, more to the point, did four Conservatives. Now an opposition can do what it pleases in the way of amendments to bills, but it is only when it begins recruiting allies on the Conservative benches that a Government gets worried. When the amendments go down on report, as this one did, the spectre of defeat is not quite so menacing as it is in a committee, since the number of Government M.p.s in the House deeply concerned by the issue may well be heavily exceeded by the number who are not. Still, in this case, there was certainly the possibility of a revolt; and in any case, " Government votes down bid to aid homeless " is not the kind of headline any administration will normally strive to earn. So on Jan. 23, when the report stage was taken, Mr Rossi, the new junior Minister at the Department of the Environment, came armed with a peacemaking proposal. No, the Government would not resume the imposition of a duty on local authorities, he said: but it did intend to issue directions; and the beauty of that was that they could attach directions to specific cases and fire them at individual local authorities. Indeed, as Mr Rossi developed his case, directives became not just an alternative to a duty but a positive improvement. It was hoped to issue a set of directions early next month, printing permitting, which would tell local authorities to arrange accommodation for those in need of care and attention, those in other kinds of urgent need, and those needing help on medical and welfare grounds. This was enough to satisfy the prospective Con-