Acid rain has been one of the first and longest running of the multi-national environmental issues. The phenomenon was described in the 1950s and 60s by noted scientists such as Dr Eville Gorham, Dr Svante Odén and Dr Harold Harvey. Scientific and public reaction to their work was generally negative.

Over the past two decades, the scientific understanding of the problem has dramatically improved. As this information became understood by the public, support for the control of atmospheric pollution increased to the point where virtually all industrialised countries are now implementing sulphur dioxide control programmes.

The industrial reaction to environmental control has become much more positive over the past few years with many industrial sectors now being equal partners in discussions of solutions to environmental problems. While pollution control programmes cost considerable amounts of money, it has been shown that these costs are manageable and that clean environments are conducive to economic development.

Opinion polls have shown that the public in Canada and the U.K., for example, places high priority on the need for environmental protection.

The positive industrial attitude, the increased public concern and the need to understand the science of complex environmental issues, in order to design the best possible control programme, together necessitate the involvement of environmental scientists in public debates if rational decisions are to be taken.

The hypothesis of reed decline being a consequence of eutrophication has been proved. Rhizomes of P. australis from two habitats differing in nutrient availability were collected during one year. In the nutrient-poor habitat, less aboveground biomass and greater starch reserves were formed in comparison with the nutrient-rich one. In the stand with a high nutrient availability, a decrease in starch content was observed in horizontal rhizomes during autumn.

Red deer, sheep and reindeer grazing on their normal hill ranges were examined at intervals over a period of four years. Samples from the digestive tract were taken at different seasons and processed in the field. The Red deer and reindeer were killed before samples were taken; rumen samples from the sheep were taken by stomach tube, but a number of animals were also killed at different seasons to correlate stomach tube and whole rumen samples. The animals sampled were representative of the general condition of the herds. Examinations were made for parasites and any pathological conditions. In most instances parasitic infections were slight. Apparent seasonal changes were found in the compositions of the diets. The Red deer and sheep ate principally heather and grass, the proportion of heather increasing in the winter. The reindeer ate mainly grass in the summer, with lichens and grass forming the winter diet, and these animals seemed to have a higher nutritional status in the winter than did the other two species. The weights of the animals and of their rumen contents, the concentrations of rumen ammonia and volatile fatty acid, and the rates at which different dietary components were fermented are recorded. Rumen fermentation was low in winter and the diets were generally inadequate for the animals. A lack of nitrogen seemed to be a major factor.

Some data on caecal contents are also given.

Material of a very small and distinctive species of Isoetes was sent by Miss Alison Baird in 1934 to Professor J. Walton, who kindly handed it over to me for examination. This species, hitherto undescribed, is here named Isoetes australis. The material, which consisted of plants of all ages from two-leaved sporelings up to adult plants, had been collected in 1930 from rock pools in granite outcrops at Bruce Rock, 150 miles inland from Perth, Western Australia.

The following description is mainly based on Miss Baird's material, but I later received air-dried plants of the same species which had been grown by Professor T. G. B. Osborn in the Laboratory at Sydney. These plants had originally been collected by E. T. Bailey from the Bruce Rock locality in 1934. They proved to be viable and commenced growth within a few days when placed in water, and I was able to keep one of them alive for a period of two years, though only in a depauperate condition. Professor Osborn also sent me herbarium specimens, collected in the same locality by Bailey, and some of these plants, which had been completely dry for six months or longer, proved viable, though I was unable to grow them on for more than a few months.

Marcet reported in 1822 that sea salt contained lime, and several investigators confirmed its presence in sea water in the 1830s. Darondeau found dissolved CO2 in sea water in 1838, and von Bibra in 1851 considered sea water to be slightly alkaline. Tornöe in 1880 pointed out that this condition required part of the CO2 to be bound chemically, and Hamberg applied the mass action law to the CO2-system in sea water in 1885. For nearly 50 years, however, despite the development of the concepts of pH and activity, attempts to apply the law in detail failed, first because the behaviour of H2CO3 and HCO3− as weak acids is strikingly different in pure water, sea water or NaCl solutions, and secondly because the presence and role of another weak acid, boric acid, was not recognised fully until 1933. Investigators often attributed their failures to some mysterious ability of the sea to disregard or evade the laws of physical chemistry. Buch in 1933 and 1938 finally laid this hobgoblin to rest, and his results are still accepted with only minor modifications.

The ecological role of native willows is described in terms of the diverse structure of the species involved, the wide range of plant communities they form and the large numbers of invertebrates associated with them. The conservation importance of the genus Salix is discussed along with comments on the necessary management to retain willow habitats.

Uptake of oestrogens into breast tissue and their subsequent metabolism can be studied by infusing radio-labelled steroids into volunteer patients. Such studies show that oestradiol is preferentially accumulated in breast tumours, oestradiol concentrations exceeding those of oestrone. This contrasts with plasma, in which oestrone concentrations in postmenopausal women are greater than those of the oestradiol. This observation suggests that tissue factors can modulate local oestrogen metabolism, and thus local steroid concentrations.

We have studied the local production of oestrogens from androgen, and also the interconversion of the major oestrogens, oestrone and oestradiol. Using isotopic techniques, it is possible to calculate the proportion of endogenous oestrogen produced from androgen, as opposed to uptake from the circulation. These studies suggest that a very variable proportion of tissue oestrogen derives from endogenous synthesis. After administration of aromatase inhibitors, aromatase activity is substantially inhibited, both in vivo and in vitro.

Relative oestrogen concentrations are determined in part by the activity of oestradiol dehydrogenase. In breast tissue, dehydrogenase activity is present and this is modified by various factors, including androgens. In addition, we have demonstrated that normal, benign and malignant breast tissues produce factors which can modulate both growth and dehydrogenase activity of cancer cells in vitro.

We conclude that breast tissue is a site of synthesis of oestrogens, and that a number of factors can affect their local concentration. Tumour cells produce growth factors which can influence steroid metabolism, and may thus be able to enhance favourably their own endocrine environment.

Experiments have shown that Sitka spruce on poor soils requires relatively frequent applications of fertiliser, phosphorus being most commonly required, other deficiencies in decreasing frequency being potassium, nitrogen and, very rarely, copper. Recent evidence suggests that growth responses to fertilisers are commonest while stands are young and the green canopy is being established. Spruce has a heavy crown and in consequence nutrient demands are high prior to canopy closure. Thereafter, the annual production of foliage by spruce is no greater than that of other species of comparable growth rate and by this stage the establishment of cycles within the tree and through the litter layer enable efficient re-use of nutrients and hence the demands placed upon the soil fall dramatically.

Young Sitka spruce trees grow slowly, compared with poplar for instance, because of lower photosynthetic rates and slower rates of leaf area production. On the other hand, the canopies of Sitka spruce stands have structural and photosynthetic properties which make them very productive. Both the slow growth of young trees, and the high productivities of closed stands, can be attributed to the needle habit.

While the role of oestrogens in breast cancer has been recognised for over a century, until recently our understanding of the mechanism by which they act has been limited, despite zealous efforts on the part of many investigators to seek for differences in oestrogen levels or metabolism in cancer patients. Since the initiation of breast cancer occurs many years before the detection of overt disease, it seems reasonable to suggest that these earlier studies may have been carried out at the wrong stage of the disease. Using a time invariant radiometric procedure, we have established that of the three principal sites of oestrogen metabolism at C-2, C-16α, and C-17, only C-16α hydroxylation is elevated in women with breast cancer. Further studies in women at high risk for breast cancer for familial reasons showed that they have an elevated rate of 16α-hydroxylation. Parallel studies in mice with high and low rates of spontaneous mammary tumour formation show a close parallelism between the extent of 16α-hydroxylation and tumour incidence. Studies of 16α-hydroxyoestrone, the product of 16α-hydroxylation, have demonstrated that it is a unique oestrogen, capable of binding irreversibly to the oestrogen receptor and permanently activating it. Studies on the effects of diet and drugs on the extent of C-2 and C-16α hydroxylation have shown that while the former reaction is easily increased or decreased, the latter is refractory to treatment and behaves like a constitutive enzyme. Thus, treatment with cimetidine, obesity, or high fat diets decrease the extent of C-2 hydroxylation, while high protein diets, hyperthyroidism, smoking, or dioxins increase C-2 hydroxylation. In contrast, 16α-hydroxylation is essentially unchanged in any of these conditions.

A link between increased C-2 hydroxylation and decreased levels of breast and endometrial cancer is suggested by epidemiological studies in smokers. Conversely, decreases in this reaction as in obesity are associated with increased risk for these tumours. The aim of these studies is to develop a safe prophylactic regimen which will increase C-2 hydroxylation, resulting in a decrease in active oestrogen and a lower tumour incidence.

The topographic and sedimentary characteristics of the Voe are briefly described and used to define the distribution of epifaunal and macro- and meio-infaunal communities throughout the Voe. The structural complexity of the communities, their interdependence on one or a group of dominant species, and their trophic relationships are emphasized. Changing distributions with depth and in time are examined in detail, particularly in relation to the intermittently eutrophic conditions occurring in the inner basin of the Voe.

Data from the Clyde demersal fishery during the period 1960 to 1984 are presented. Annual landings of demersal species at Chde ports in recent years have ranged from 4000 to 10,000 tonnes, with a first sale value of £2–5 million. In the 1960s the fishery was undertaken mainly by seine-net vessels, but the present fleet consists largely of dual-purpose light/Nephrops trawlers. The demersal fishery is seasonal and during the winter and spring there is an influx of ‘stranger’ vessels. Five species (cod, whiting, saithe, hake and haddock) make up more than 80% of the demersal landings from the Clyde. The landings of saithe have fluctuated very considerably during the period under review. Other relatively important species are dogfish, plaice, skate and ray and angler fish. In general the Clyde fishery represents only a small proportion of the total Scottish landings but in recent years landings of hake from the Clyde grounds have averaged approximately 40% of the Scottish hake total. The Clyde demersal fishery depends to a large extent on young fish and both the total annual landings and the relative importance of the principal species fluctuate from year to year in response to variations in the strength of the recruiting year classes. The catch rates of the principal species vary greatly throughout the year. Although there is no conclusive evidence that the Clyde populations are self-contained, all the major species are known to spawn within or close to the area and tagging experiments have suggested that there may not be much mixing between Clyde fish and those from surrounding areas. This may in part, however, reflect the fact that fishing intensity within the Clyde is high and fish are recaptured before they have had time to leave the area. For management purposes, the Clyde demersal stocks are included in ICES Sub-area VI.

Tradescantia pollen grains are excellent material for the analysis of X-ray effects. The influence of radiation on cell development, nuclear differentiation, as well as on chromosome structure can be studied. Extensive quantitative analyses, which primarily concern the mechanism of chromosome breaks and reunions induced by radiation, have already been made (Riley, 1936; Sax, 1938, 1940, 1941; Fabergé, 1940). The present paper contains data which show the effects of radiation on cell development, chromosome behaviour, nuclear differentiation, and pollen germination. It is expected that the data obtained will throw some light on the intricate mechanism present within the cell and show that the governing centre of this mechanism is the nucleus.

The stomodæum appears as an ectodermal invagination. The oesophagus develops from an outgrowth (posterior) and the radular sac from a ventral evagination of the floor of the stomodæum. The basal epithelium of the radular sac secretes the radular membrane and the teeth, while the dorsal epithelium contributes towards the hardening of the teeth. The subradular cavity is formed from a depression of the floor and the salivary glands from two evaginations of the roof of the stomodæum. The buccal cartilage is mesodermal, while the jaw is ectodermal. The blastopore closes. Only the posterior part of the archenteron takes part in the formation of the gut, from which the crop, stomach and the digestive gland develop. The anterior chamber of the crop develops from a diverticulum of the archenteron. The anterior and posterior lobes of the digestive gland arise from the anterior part of the primitive stomach dorsally and on the left side respectively; the posterior chamber of the crop from the anteroventral region of the primitive stomach, and the stomach from the posterior right side of its floor. The hind gut appears by the arrangement of cells proliferated from that part of the archenteron where blastopore closes. It opens anterodorsally into the primitive stomach in a 2½ mm. embryo; the anus appears in a late embryo about 12 days old.

In previous contributions the writer has described the structure and behaviour of the mitochondria and Golgi material of the egg of the mouse (Gresson, 1933, 1938 and 1940 b), and more recently has traced the cytoplasmic inclusions through the stages of maturation, fertilisation and the first cleavage division (Gresson, 1941). As the result of observations on the sperm middle-piece it is claimed that the mitochondria of the sheath are liberated into the ooplasm of the fertilised egg, and are shared out between the first two blastomeres; and further, that a Golgi element is present in the middle-piece, and that this breaks up and its products are distributed through the cytoplasm of the fertilised ovum (Gresson, 1940a, and 1941).

Weedy nature and critical taxonomic status of widespread autogamous annual brome-grasses combine to make assessments of their native phytogeographical areas uncertain or impossible. Suggested criteria for determining native status are reviewed. Some species found in SW Asia occur also in Europe. Some others are so far known only in Europe and may either be native there or introduced from SW Asia. These possibilities are considered by applying native status criteria to 10 principal exemplar species and 4 subspecies. On the basis of known distributions, these criteria suggest that: (i) some species are not native in any primary habitats, and perhaps never have been; (ii) though SW Asia seems to be the centre from which the current adaptive radiation of Bromus L. annuals began, not all its brome-grass flora is native, and some of its probable native species are known only as introduced plants in Europe i.e. are undiscovered in SW Asia. It is urged that our imperfect knowledge of distributions in this critical group be remedied by careful analysis of the brome-grass flora of primary habitats in SW Asia.

The fish populations of the Rockall Trough were poorly known until the early seventies, when there was an interest in the possible exploitation of the demersal fish of the upper slopes. These surveys were carried out by fisheries laboratories with commercial trawls fished on paired warps. At the same time the SMBA began an investigation into the seasonal aspects of the fish of the slopes, using paired warp and single warp otter trawls and an Agassiz trawl. These studies have resulted in a wealth of information on the fish collected by several towed gears and have enabled comparison to be made between different trawls. Of particular interest has been the difference in abundance and biomass estimates between paired and single warp trawls. The small amount of information on the biology of the fish species is briefly reviewed and the populations of the Rockall Trough are considered in the broader context of the northeast Atlantic.

The sediments of the floor of the Tay Estuary are dominated by assemblages of quartzo-feldspathic sands, although pebbles and silts are locally important. The sands are principally of inorganic materials, but they include shell fragments which account for up to 25% of the material, depending upon locality.

Detailed analyses of the shell components of the 0.3–1.2 mm size fraction (400 particles from each site) in the area between Balmerino and Monifieth Bay reveal the presence of much molluscan debris (identified as mature and immature bivalves and gastropods), with significant proportions of bryozoan, barnacle or echinoderm skeletal fragments according to locality. Ostracoda and foraminifera are less common. The shelly material occurs mostly within zones inhabited by the same living organisms.

The characteristic blue-coloured Mytilus edulis shell fragments are also recognised up to 6 km landwards of the westernmost known colonies, along the railway bridge.

Shell matter is dissimilar in shape and surface texture to the clastic grains and large shell fragments are frequently associated with sand sized inorganic sediments, which have been shown in flume experiments to respond in a similar manner to hydraulic controls.

The Mytilus is therefore suitable for use as a natural tracer. It indicates up-estuary net residual motion of sediments in the middle and upper reaches. This pattern confirms evidence from heavy mineral assemblages that North Sea derived sands enter the estuary and migrate westwards to accumulate on the upper estuarine tidal flats.

The waters and coastal margins of the estuary and Firth of Forth are important and very valuable biological and recreational resources. They also receive, directly or indirectly, the aqueous domestic and industrial wastes of a quarter of the population of Scotland. It is one task of the Forth River Purification Board to minimise and eventually eliminate any conflict between the effects of these discharges and the various legitimate uses of the waters. Some of the main causes of environmental stress are briefly outlined and the basic strategy by which the problems will be overcome is described.

The mature Ptinid sperm examined under the light microscope is found to be specialised in that the chromatin is not contained within a sperm head but is distributed along a central axis. The migration of chromatin resembles that found in Coccids by Hughes-Schrader (1948). Surrounding the axis is a more flexible helical membrane extending the whole length of the sperm.

Under the electron microscope the membrane appears to consist of eighteen or twenty thin fibres and two thick fibres with striated sheaths. Near the posterior end of the membrane the fibres are surrounded by a ring. The structure is simpler than that of mammalian and avian sperms examined by other workers with similar techniques. Under the electron microscope, stages in the migration of chromatin in the immature sperm show a number of discrete opaque bodies which may be chromosomes. The approximate dimensions of the various structures are given.