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1. The neo-natal death rate among premature babies is very much higher than that among mature babies, and as a result of the changing pattern in infant mortality in recent years prematurity has become relatively more important as a cause, or contributing cause, of infant deaths. 2. When surviving premature children are compared with surviving mature children it has been found that the premature children are at a disadvantage in various respects. 3. For these reasons it is important to attempt to reduce the incidence of prematurity, but this object is hampered by inadequate knowledge of the aetiology of prematurity. 4. A premature child is defined as a child who weighs 5 1/2 lbs. (2500 G.) or less at birth, regardless of the length of gestation. In spite of its faults, this is the best definition available. 5. The aetiology of prematurity is not fully understood. In about half the cases of prematurity which occur no cause can be defined. In the remaining half the prematurity is associated with complications of pregnancy and it is generally assumed that these complications are the cause of the prematurity, but the way by which this is brought about is not known. It is known that a large number of factors such as social class, maternal age, and parity influence the prematurity rate. It is also known that prematurity tends to be repeated and this tendency may be associated with a tendency to abort and show signs of toxaemia. 6. The aim of this study was to examine the occurrence of prematurity against the background of the reproductive tendencies of the mothers of premature children. In order to do this, we interviewed the mothers of 515 single-born premature children who had been born in Glasgow during the year 1950, and obtained the obstetric histories of these mothers. There does not appear to be any bias in the sample which would influence the conclusions which will be drawn. 7. The incidence of prematurity among the single-born sib- lings of these premature childre

Ore deposits form by a variety of natural processes that concentrate elements into a small volume that can be economically mined. Their type, character and abundance reflect the environment in which they formed and thus they preserve key evidence for the evolution of magmatic and tectonic processes, the state of the atmosphere and hydrosphere, and the evolution of life over geological time. This volume presents 13 papers on topical subjects in ore deposit research viewed in the context of Earth evolution. These diverse, yet interlinked, papers cover topics including: controls on the temporal and spatial distribution of ore deposits; the sources of fluid, gold and other components in orogenic gold deposits; the degree of oxygenation in the Neoproterozoic ocean; bacterial immobilization of gold in the semi-arid near-surface environment; and mineral resources for the future, including issues of resource estimation, sustainability of supply and the criticality of certain elements to society.

Ore deposits form by a variety of natural processes that concentrate elements into a small volume that can be economically mined. Their type, character and abundance reflect the environment in which they formed and thus they preserve key evidence for the evolution of magmatic and tectonic processes, the state of the atmosphere and hydrosphere, and the evolution of life over geological time. This volume presents 13 papers on topical subjects in ore deposit research viewed in the context of Earth evolution. These diverse, yet interlinked, papers cover topics including: controls on the temporal and spatial distribution of ore deposits; the sources of fluid, gold and other components in orogenic gold deposits; the degree of oxygenation in the Neoproterozoic ocean; bacterial immobilization of gold in the semi-arid near-surface environment; and mineral resources for the future, including issues of resource estimation, sustainability of supply and the criticality of certain elements to society.