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This report deals with cross-sectional growth of sitting height (SH), subischial length (SL, estimated as height minus sitting height), height of the anterior superior iliac spine (HIS), and total arm length (TAL) of Bengali school boys (Calcutta), aged 7·0–16·0 years. Preece-Baines model 1 (PB1) fits to the cross-sectional means of the four traits estimate the average ages at maximum increment at 12·41 years for SL, at 12·43 years for HIS, at 12·97 for TAL, and at 13·74 years for SH. Maximum increment of the upper and lower segment of the body are reached at an earlier age in the present study than in a longitudinal analysis of semi-urban Bengali boys from the suburban area of Calcutta. Socioeconomic differences and secular trend might explain this shift towards earlier maturation.

The effect of parity on placental weight and birth weight is examined through a series of birth records from an Indian population in Calcutta. Placental weight and birth weight increase with parity, the maximum increment occurring between parities 1 and 2. This is compatible with a hypothesis of sensitization of the mother to foetal, paternally derived, antigens.The three common placental alkaline phosphatase enzymic genotypes have no effect on determining foetal development.

798 placentas (Brahmin 141, Kayastha 303, Mahishya 91 and mixed low castes 263), from Calcutta hospitals, have been studied by starch gel electrophoresis for alkaline phosphatase types.The estimated gene-frequencies resemble those found else-where in caucasoid populations. Statistically significant differences (P∼0·02) were, however, noticed between the broadly divided upper caste group (Brahmin and Kayastha) and the lower caste group (Mahishya and mixed low castes) in respect of Plf1 and Pls1 gene distributions. The upper caste group has higher Plf1 and lower Pls1 frequencies than the lower caste group. The two broad caste groups are, however, quite uniform in Pli1 distribution.All the six common phenotypes (S1, F1, I1, S1F1, S1I1 and F1I1) and seven rare phenotypes (S1S2, S1S3, F1F2, F1S2, F2S1, F1S3 and I1S2) were found.

The Preece-Baines Model 1 curve has been fitted to longitudinal data on growth in height of 105 boys and girls in 70 Bengal families: 60 of these were sibs distributed in 25 families. For a number of growth characteristics, such as age at peak height velocity, the proportion of the total population variance that was due to variation between, as opposed to within, families was estimated by Smith's (1980) method. The proportions for age at take-off of the adolescent spurt, of age at PHV, and of PHV itself were 22%, 26% and 33% (where adult height gives a value of about 40%). The sample is small and these estimates have high standard errors and need confirmation.

This study is the first Indian longitudinal growth survey from early childhood to maturity. The heights of 303 boys and 260 girls, from middle-class families in a semi-urban area south of Calcutta, were measured at regular intervals over periods of up to 14 years (between 1952 and 1966). The data were analysed using appropriate mixed longitudinal and curve-fitting techniques.Growth in height of these middle-class Bengali children, who are not a representative sample of the Indian population, is slightly above the national Indian Council of Medical Research Standards. In both sexes, mean heights are below the 10th centile line of the British standards from an early age onwards, mainly due to a smaller prepubertal growth.The adolescent growth spurt in the Indians is similar to that seen in British children, as is the age at which it occurs (peak height velocity at 14·0 years in boys, 12·5 years in girls). The sex difference of 14·0 cm in adult stature is attributable to a greater adolescent gain in the boys of 6·0 cm, a greater height in boys at the girls' age at take-off of 3·3 cm and a gain in height by the boys of 4·7 cm between the girls' and boys' ages at take-off.