1085

detected even in an early morning specimen. (Mostlaboratories now ask for a repeat specimen if the test isnegative and the specific gravity less than 1-015.)Much has been written about the accuracy of individual

tests. Enein and Sharman 20 showed that Gravindex ’, a’slide-test using latex particles, was accurate enough to beused for quantitative estimation of H.C.G., and was thususeful in assessing the prognosis of threatened abortion.Bell 21 compared five separate pregnancy tests in parallel-’Planotest’, ’ Gravindex’, ’Pregslide’, ’Hyland B ’,and the haemagglutination-inhibition test, pregnosticon-in 686 early morning urine specimens. The false-

positive rates ranged from 0-5 to 4-7%, and the false-negative rates from 0-5 to 9%. Of the slide tests,planotest gave the most reliable results.A major advance in pregnancy testing was the intro-

duction of tests which could detect H.c.G. in serum or

plasma as well as urine. Since gonadotrophin levels aremuch steadier in plasma than in urine, the test is probablyconsiderably more accurate than previous slide-testmethods. H.C.G. can be detected in blood as early as thefourth day after a missed period. The test is based on theuse of latex particles coated with anti-H.C.G. serum. Thecoated particles agglutinate on the addition of fluids con-taining 1 or more i.u. of H.C.G. per ml. As with theinhibition tests, false negatives can result if very largequantities of H.C.G. are present, as in hydatidiform mole orchorion carcinoma; so, if abnormal pregnancy is suspected,falling dilutions of urine should be tested. It remains to beseen whether this simple, cheap, new slide-test will achievethe 99% accuracy of the Hogben or hamiagglutination-inhibition tests; but as a do-it-yourself outfit for the

physician it has many advantages.

BOYS BEFORE THE COURTS

WHAT makes a child an habitual offender ? The

frequency with which boys reappear before the courtssuggests that any treatment they receive has little effect.Their parents, social workers, and teachers often have towatch what seems to be a relentless progress. In alecture at the National Institute for Social Work Trainingon May 8, Mr. Michael Power, of the Medical ResearchCouncil Social Medicine Research Unit, described a

study of juvenile delinquency in Tower Hamlets, London.In this borough boys between the ages of 10 and 16appear in court at double the rate for England and Wales.Mr. Power’s group found that, of 1500 boys born therein 1949, 424 had made a total of just over 900 courtappearances. In an attempt to account for this highdelinquency-rate he analysed three major influences onthe boys-neighbourhood, school, and family.There were pronounced regional differences in delin-

quency. In some areas nearly all the boys had appearedbefore the court, but in others hardly any. Thesedifferences were longstanding, and could not be explainedin terms of population movements, or of variations inthe vigilance of the police; nor was there any correlationwith social-class distribution. For reappearances in

court, the regional associations were not so strong.When a group of offenders from the same area camebefore the court, it usually consisted of one boy with arecord of frequent appearances, accompanied by " new "boys attending for the first time. An investigation of20. Enein, M. A. A., Sharman, A. J. Obstet. Gynœc. Br. Commonw. 1967,

74, 583.21. Bell, J. L. J. clin. Path. 1969, 22, 79.

schools also showed wide variations in court-appearancerates-from 0’6 to 13-3% per year. Bad schools in thisrespect tended to remain bad, and there was no apparentrelation between delinquency and the child’s ability orthe parents’ choice of school. Primary schools wereunable to spot potential offenders. Reappearance-rateswere as strongly related to schools as first-appearance rates.A special study of first offenders revealed that, of those

who reappeared in court, three-quarters came from dis-rupted families. Taking into account five factors-clinical assessment, family, school, delinquency group,and neighbourhood-Mr. Power’s team was able to

predict with 84% accuracy whether a first offenderwould come before the courts again. The family was asimportant a factor as all the others put together. Thesecriteria for making accurate predictions may prove of thegreatest importance to the courts, which, faced with afirst offender, often have little help in deciding whatshould be done.

RUBELLA VACCINES

RUBELLA vaccine made from the Cendehill strain isnow on sale in Switzerland, and is expected to belicensed in other countries in Europe this summer. Itis widely forecast that the HPV 77 strain will be licensedfor sale in the U.S.A. in June. The report 1 of an inter-national symposium on rubella vaccines, held in Londonin November, 1968, has just been published, and sohave two authoritative reviews.2 3 The pressure to

introduce a vaccine in the United States is intensebecause there was an extensive outbreak in 1964-65, withmany congenital abnormalities due to rubella infection, "and it is hoped to introduce vaccine before the nextepidemic, expected early in the 1970s. There is also

heavy commercial and scientific pressure to secure thefirst rubella vaccine, as there was to introduce the firstpoliovaccine. It is to be hoped that caution will preventan incident like the Cutter disaster which followed thehasty acceleration of poliovaccine production. Certainlymuch more stringent requirements must now be metbefore any vaccine can be marketed. As Dudgeon 2

notes, three main questions remain to be studied further:first, the best cell substrate (primary simian rabbit oravian cells or a human diploid cell line) ; second, the effectof attenuated rubella on the fetus: third, qualitative andquantitative aspects of immunity, in particular its duration.

Efforts to prepare a killed rubella vaccine have notbeen very successful. Buynak et al. reported that a

purified, concentrated vaccine produced antibodies butdid not prevent reinfection. Moreover, since protectionof adult women is the object, it is highly desirable toinduce long-lasting immunity. At present most virolo-

gists believe that this aim is more likely to be attainedwith a living vaccine than with a killed one. Cases,recently reported from the U.S.A., of measles in childrenwho have had Enders B or Schwartz strain of measlesvaccine may have been due to some failure in the vaccina-tion procedure, but they may also be due to waningimmunity.5 They certainly inspire caution in assuming1. International Symposium on Rubella Vaccine (edited by R. H. Regamey,

A. de Barbieri, W. Hennessen, D. Ikic, F. T. Perkins). Basle, 1969.2. Dudgeon, J. A. Br. med. Bull. 1969, 25, 159.3. Parkman, P. D., Meyer, H. M. Prog. med. Virol. 1969, 11, 80.4. Buynak, E. B., Hilleman, M. R., Weibel, R. E., Stokes, J. E. J. Am.

med. Ass. 1968, 204, 195.5. National Communicable Disease Center: Morbidity and Mortality,

1969, no. 18, p. 141.