Child welfare clinics established in a rural Jamaican community for research purposes are described. These special clinics were able to devote more resources to the care of their children than is usual, yet the growth and health of these children were very similar to those in another group to whom this service was not available and who attended routine government welfare clinics only infrequently.

Heights and weights were measured of 5600 children aged 5 to 14 years, of predominantly African origin, attending primary schools situated in rural areas of St Vincent. The mean size of these children was intermediate between that of London children recorded in 1905 to 1912 and in 1959 and not greatly different from that found in recent years in most other parts of the West Indies. These St Vincent children were larger than those measured in a small survey 20 years ago. For a given height, they were lighter than London children in 1959 and obesity was much less common. Signs of serious malnutrition were rare. A standard of mean heights and weights of West Indian children from lower socio-economic classes and of predominantly African origin has been calculated from the results of recent surveys in five different countries.

An analysis of pregnancy and fertility trends, utilizing the Bogue pregnancy history technique, indicates that pregnancy and fertility declined by approximately 27% in a rural area of East Pakistan between 1958 and 1967. The results reflect the impact of the organizer approach to family planning as well as of the commercial distribution programme. If the present trend continues, it could be expected that women in the more fertile age groups of 15 to 19 years and 20 to 24 years will show a greater reduction in total pregnancy and fertility rates than those in the older age groups. It appears also that foetal mortality may play an important role in affecting variation in fertility in particular segments of the age structure. This suggestion, however, should be treated with caution since the presence of sampling errors could have affected the apparent incidence of foetal mortality.

Age-specific mortality rates have been used to illustrate certain aspects of the characteristics of old age. A consideration of the experience of the ageing person in his fifties and early sixties suggests that during this period he comes to recognize death as being an increasingly common characteristic of his age group. Thus the standard procedure for studying old age problems in a sample of people over the age of 65 may miss the period of life when people are making the crucial adjustments to old age and may give a distorted view of some gerontological problems. Certain demographic aspects of old age are considered in detail with regard to the occurrence of, first, widowhood and, second, social isolation.

Data concerning occasions of coitus were recorded by 241 married couples who had sought advice from the Catholic Marriage Advisory Council about the basal body temperature method of regulating births. The present analysis deals with the 6 days of the post-ovulatory phase which are considered to be least affected by intended birth regulation. The distribution among couples of coital frequencies is tabulated by age of wife; the mean frequency during the 6 days is 1·8 (Table 2) but this value may be influenced by the fact that some couples had avoided coitus in the pre-ovulatory phase. The hypothesis is examined that the probability of coitus on any day is unaffected by whether or not coitus occurred on the previous day. Sufficient data are available to show, as expected, that not all couples behave in the way described by this hypothesis. It is estimated that for about a third of the couples the probability of coitus is decreased if it occurred on the previous day (alternators). There are also significant numbers for whom it is increased (persisters), besides those conforming to the hypothesis.

The Twelfth Oliver Bird Lecture was delivered by Professor Richard Doll, Regius Professor of Medicine in the University of Oxford, at the London School of Hygiene and Tropical Medicine on 19th March 1970. This was the last lecture to be given under the auspices of the Oliver Bird Trust, an account of which starts on page 359. Professor Doll was formerly Director of the MRC Unit of Medical Statistics, in which capacity he had exceptional experience in assessing the significance of changes in the incidences of abnormal conditions. The subject of his lecture was therefore highly appropriate to his special knowledge, as well as to current controversy and to the series of Oliver Bird lectures. The Journal of Biosocial Science is glad to publish this authoritative exposition of a most important problem.