There is a high incidence of cancer in beef cows in certain sharply localised geographic calf-rearing areas in Britain and also in cattle in several other parts of the world. The tumours occur on farms which are highly infested with bracken fern and which have a history of bracken poisoning. Bracken is known to cause intestinal and bladder cancer in rats and recently the flavonol, quercetin, has been shown to be a mitogen and to be carcinogenic in rats. Bracken contains large amounts of quercetin. In addition the animals have a high incidence of papillomas of the alimentary tract and these transform to malignant tumours. A new and unique papilloma virus has been isolated from these tumours. Studies using genetic engineering and DNA hybridisation techniques have shown that both alimentary and urinary bladder tumours contain viral DNA sequences. The relationship between bracken, quercetin and viral DNA sequences is under investigation both in cattle and at the molecular biology level as two possible stages in a multi-stage process in the aetiology of a high incidence naturally occurring cancer.

Certain aspects of the cytology of germination of spores of Anemia phyllitidis and Pteris vittata, with particular reference to the role of nucleic acid synthesis, are reviewed. As studied by autoradiography of 3H-thymidine or 3H-uridine incorporation, spore germination resulting in the formation of the rhizoid and protonemal cell is accompanied by the synthesis of DNA and RNA. Experiments using inhibitors of RNA synthesis on gibberellic acid-induced germination of spores of A. phyllitidis have indicated that dry spores contain conserved mRNA and that gibberellic acid-induced polyadenylation of mRNA occurs during the early phase of germination of spores. Recent demonstrations of the presence of polyadenylated mRNA in dry spores of A. phyllitidis suggest specific roles for both functional, conserved mRNA containing polyadenylic acid, as well as for gibberellic acid-induced polyadenylation of mRNA during the early phase of spore germination.

Centred on Loch Druidibeg, macrophyte vegetation was surveyed in and around 30 lochs in northern South Uist. Alkalinity ranges from 0·014 to 2·33 m.-equiv −1, conductivity (25°C) from 100 to 33,900 μs cm−1, chlorinity from 0·66 m.-equiv −1 upwards. Lochs are classed broadly as non-calcareous (gneissic), calcareous (machair) and brackish. This is an example of a Hebridean range not found elsewhere in the British Isles. Fen vegetation is highly modified by grazing, whilst tall reedswamp and floating-leaved plants are scarce on the mainly exposed and rocky shores, factors which contribute to the predominance of Fucoids in brackish water, of the open Littorella-Lobelia association in non-calcareous water. The Potamogeton filiformis-Chara association is confined to sand in calcareous machair lochs. Deep freshwater vegetation is typified by Isoetes, Potamogeton perfoliatus and P. praelongus.

The very wide ranges in alkalinity and conductivity are reflected in some unusual species' distributions. For example, in freshwater lochs (conductivity up to 660 μs cm−1) several species like Isoetes lacustris, confined elsewhere to oligotrophic water, also occur in South Uist at moderately high alkalinities (to 1·8 m. -equiv 1−1). Conductivity varies with chloride concentration in all but the calcareous (machair) lochs; brackish lochs range from 2500 μs cm −1), which floristically, apart from Fucus ceranoides, is fresh water, to Fucoid-dominated rocks, and Ruppia on silt, in conductivities up to 33,900 μs cm−1. Of other angiosperms, Potamogeton gramineus appears to tolerate conductivities of 22,000 μs cm −1. Causal distribution in general is discussed.

The main facts about the life history of Atlantic salmon have been known for a surprisingly long time. Neill (1946) gives an account of early writings on this subject which makes it clear that, for over four hundred years, it has been known that salmon breed in fresh-water, that they spend a period there before migrating to the sea and that, once in the sea, they undertake long migrations. These earlier writers tended to underestimate the period of time spent in the sea (e.g. they thought it likely that salmon returned to fresh water in the same year that they migrated to sea) but, otherwise, their knowledge of the life history of salmon was remarkably complete and accurate.

Data from the Continuous Plankton Recorder survey are used to compare the distribution and seasonal and year-to-year variations in the abundance of the plankton of the area of the Rockall Channel with both the shelf and the adjacent oceanic areas. It is argued that the distribution and size of overwintering stocks of zooplankton provide the key to understanding the dynamics of the plankton of this area.

It would appear that, due to inherent limitations to the net rate of increase of zooplankton populations, the distribution of the overwintering stocks has an influence on the distribution and abundance of most species through the rest of the year. This affects the dynamics of the seasonal cycle and also influences the form of year-to-year changes in abundance

The plankton of the area of the Rockall Channel is characterised by low overwintering stocks, coupled in spring with higher rates of population increase as compared with the adjacent shelf. There is a pronounced spring bloom of phytoplankton, which does not appear to be controlled by grazing, followed by a period of nearly five months of relative stability of stocks of both phytoplankton and zooplankton. It is suggested that during this period the zooplankton graze the daily production of phytoplankton, the growth of which is determined to a large extent by nutrients recycled from the zooplankton. The effects of this pattern of dynamics on the form of year-to-year changes in the abundance of the plankton over the last few decades is discussed.

The paper describes the salmon and sea trout stocks of the rivers entering the sea via the Estuary and Firth of the Clyde including the Rivers Clyde, Leven, the Carts, the rivers of the Ayrshire coast and those entering via the sea lochs and from the Mull of Kintyre. Particular attention is paid to the recent return of salmonids to the Rivers Clyde and Cart, which have been denied to migratory species for over a century because of pollution in the upper Clyde Estuary. The changing environmental conditions, which have made the reappearance of migratory salmonids possible, are described and the future importance of the fishery assessed.

The chemical, physical and biological properties of asulam make this herbicide well suited for the selective control of bracken in various situations. These properties are reviewed and conditions considered to optimise the control of bracken and minimise the effect on the environment on both a short- and long-term basis.

The role of surfactants and mineral oils is considered.

Past studies of the relationships between different populations of Coregonus have demonstrated the great plasticity of form exhibited by this genus throughout the Palearctic region. In addition to standard morphological accounts, hybridization and rearing studies are important in attempting to assess the relationships between different races, and this paper describes some initial work which has been carried out in this direction. The development of eggs of the Loch Lomond powan, Coregonus clupeoides Lacépède, has been studied in the laboratory and shown to follow a definite pattern. The average incubation period at 6–9° C is 65 days though considerable variation in this time occurs. Eggs and sperm kept separate and without water still showed 50 per cent fertilization after 3 days but none after 6 days. Hybrids of two races of Coregonus, one living in Scotland the other in Wales, were produced by bringing together eggs and sperm which had been kept cool and dry during transport. The value of these experiments in relation to past and future research is discussed.

The river Tay receives water from an area covering over 2500 square miles of Scotland and has a discharge which is greater than that of the Severn and the Thames combined. It is, in addition, the least polluted of our major British rivers today. It thus provides a composite sample of the waters draining through much of east central Scotland, it provides a baseline for studies on other major British rivers, and with the impending upsurge in industrial activity along the Scottish east coast with the discovery of oil and gas in the North Sea, the importance of having a baseline against which future environmental changes can be measured is now a matter of urgency.

Chemical oceanography is fundamentally concerned with the chemical properties of sea water. In order to study these properties, and the interactions of sea waterkwith other phases, we must first have some concept of what sea water.

Inhibitors of the aromatase enzyme represent a class of therapeutic agents which potently inhibit oestrogen biosynthesis in vivo. This inhibition of oestrogen biosynthesis is well established as effective therapy in the treatment of oestrogen-dependent breast cancer. CGS 16949A [4-(5,6,7,8-tetrahydroimidazo-[l,5-a]pyridin-5-yl)-benzonitrile hydrochloride] is a non-steroidal imidazole derivative which is a potent competitive aromatase inhibitor in vitro. At a maximally effective concentration, it selectively inhibits aromatase and does not affect glucocorticoid production from the adrenal in vitro.

In vivo in the rat, CGS 16949A effectively reduces ovarian oestrogen content and potently inhibits an aromatase-mediated androgen-induced uterine hypertrophy. Oral treatment of adult, cyclic female rats with CGS 16949A disrupts cyclicity, inhibits ovulation, reduces uterine weight and suppresses serum oestradiol, all expected sequelae of oestrogen deprivation. At maximally effective doses, there is no evidence of adrenal hypertrophy, indicating that adrenal steroidogenesis is unaffected. In the DMBA-induced mammary carcinoma model in the rat, CGS 16949A caused almost complete regression of palpable tumours and significantly suppressed the appearance of new tumours at a maximally effective oral dose. Thus, CGS 16949A is a potent and selective inhibitor of the aromatase enzyme. In the rat, it is very efficacious in inhibiting oestrogen biosynthesis and in suppressing the growth of DMBA-induced mammary tumours.

The relative resource value and use of the Estuary and Firth of Clyde have varied through time. Until the eighteenth century the estuary was difficult to navigate. The firth, with its rich fishing grounds and sheltered harbours, was the focus of early settlement. However, increasing trade with the Americas, larger ships and growing competition between Glasgow and the more accessible ports of Greenock and Dumbarton stimulated plans to improve the navigability of the estuary. This was achieved by deepening and widening the main channel, a process which continued as the size of ships increased and more sophisticated techniques of river improvement developed. Within a century and a half the bed of the estuary was transformed from an obstacle to navigation into a major water-route, from which the largest passenger liners in the world were launched.

Since the Second World War the relative resource values of the estuary and the firth have changed with the increase in air travel, the decline of ship building and heavy industry on the Clyde, and the increase in the size of cargo vessels. The economic focus shifted from the estuary to the natural, deepwater harbours of the firth.

At present redevelopment of derelict docklands and industrial sites along the estuary is taking place, while the firth is suffering from the effects of economic recession. Planning is now being increasingly directed toward the development of the amenity, recreational and tourist potential of both the estuary and the firth.

In a paper entitled ‘Africa – the odd man out’ Richards (1973) pointed out that of the three main regions of tropical rain forest he recognised, namely American, African and Indo–Malaysian, the African rain forest stands out as distinct from the others. He took this view largely on the comparative poverty of its flora, the wider distribution of African plants, and the poor representation of certain plant groups such as palms, orchids and trees of the family Lauraceae. In addition, Africa is relatively poorly endowed with some life forms such as lianes and epiphytes. He attributed the uniqueness of tropical Africa to a number of possible factors. In the first place, differences may be due to climate since the uniformly high rainfall, humidity, temperatures, and absence of a regular dry season that occur in parts of the other two tropical regions are evidently rare or lacking in Africa. A distinct dry season, often of over two months, is nearly always present, and even in the central Congo basin there is usually at least one month when rainfall is less than 100 mm. Secondly, the impact of human beings on vegetation has been longer and more sustained in Africa than elsewhere, so much so that the presence of any truly primeval or so-called virgin forest is very questionable. However, it is unlikely that present day climatic factors and human interference can wholly account for the unique position of African rain forest, and historical reasons must also be sought. Thus it seems probable that the vicissitudes of climate, recorded as arid and pluvial periods in African lake sediments, have been much greater than those in the other two regions in question.

This paper reviews the knowledge of deterioration processes which occur when steel and concrete structures are situated in seawater. The basic corrosion mechanisms of steel, together with possible methods of protection, are outlined briefly. With regard to coatings and cathodic protection, recent developments to counteract the increasingly severe conditions encountered by oil-production platforms in the North Sea, are discussed. Concrete structures usually provide a naturally-inhibitive internal environment to confer protection from corrosion to encased steel reinforcements, but mention is made of the possibilities of such protection becoming ineffective during long service in severe offshore conditions.

The basic features of corrosion fatigue are described in the light of recent research but some aspects, which are of great importance for the performance of steel structures, are shown to be not well documented or understood. Corrosion fatigue of concrete structures has not been studied extensively, a particularly neglected area being the elucidation of the fundamental mechanisms of deterioration.

Changes of the in vitro morphogenetic state may be achieved for some potato genotypes, but others are unresponsive (recalcitrant). Although the biochemical basis for somatic recalcitrance is unknown, evidence suggests that two different aspects of oxidative stress may be involved. Phenolic oxidation is a major problem in manipulating cultures of woody plant species (Thorpe & Harry 1990) and lipid peroxidation has been associated with recalcitrance in monocotyledonous plants (Cutler et al. 1989; Benson et al. 1992). Both oxidative phenomena are believed to be free-radical mediated, but to date there is no reported direct evidence for the formation of free radicals during plant tissue culture callogenesis. The objectives of the present study were twofold; to assess the feasibility of using electron paramagnetic resonance (EPR) spectroscopy to detect free radicals directly in plant tissue cultures and to investigate free radical activity during dedifferentiation of responsive and unresponsive potato genotypes.

The experiments described in the present paper were undertaken as the outcome of an investigation into the possibility of securing nodule formation on leguminous roots cultured separately from the shoots. During that investigation it soon became clear that experiments on whole plants were necessary, in order to test the effect, on the nodulation of the normal whole plant, of certain conditions under which nodulation of root cultures was being attempted. It is thought that these observations on whole plants, though ancillary to the main investigation (which is still in progress), are of sufficient interest to be published separately. The observations are concerned with the effect of the following conditions or treatments on nodule development in a particular variety of pea:—

(a) Depriving the plant of light;

(b) the presence of sucrose in the rooting medium;

(c) the presence of nitrate in the rooting medium; and

(d) the presence of certain accessory growth substances, viz. aneurin and nicotinic acid, in the rooting medium.

A brief historical account of the early faunal investigations is given. Modern studies concentrate on qualitative and quantitative description and interpretation of the processes taking place within the Rockall Trough. Demographic analyses are feasible on a variety of species allowing estimation of growth and production rates. The pelagic fauna impinges on the benthopelagic environments of the slope regions of the Trough. There it is predated by populations of demersal fish. Advection of fauna takes place to the north and northeast, probably primarily in the slope current.

In several well-authenticated instances intestinal pathogens, including Salmonella species, have been isolated from water in the absence of bacteria, such as Escherichia coli, commonly used to detect faecal pollution. The present study examines certain anaerobic, non-sporing commensals of the intestinal tract as alternative ‘indicator’ bacteria. The numbers of bifidobacteria and Bacteroides fragilis recovered from faecal specimens were between 109 and 1010 per gram while the Gram-positive, anaerobic cocci numbered only about 106 per gram. In sewage, this numerical difference was eliminated by a rapid loss of viability of bifidobacteria and B. fragilis so that the counts of all three types of bacteria approximated to those of E. coli. Storage tests with aerated and non-aerated sewage established that further loss of viability of bifidobacteria and B. fragilis occurred only fairly slowly. In samples of water from the Dighty Water and River Tay Estuary, shown to be faecally polluted, the three anaerobic types of bacteria were recovered in numbers roughly equal to those of E. coli and their persistence in the surface of the bed of the Dighty Water was also at least equal to that of E. coli.

These results demonstrated that, in spite of their strictly anaerobic growth requirements, Bifidobacteria, B. fragilis and the Gram-positive, anaerobic cocci persist in aerobic, aqueous environments. If their habitat can be shown to be reasonably restricted to the intestinal tract they are likely, under special circumstances, to be useful indicators of faecal pollution.

Grey seals (Halichoerus grypus) and common seals (Phoca vitulina) both occur in Orcadian waters. In previous centuries they formed an important resource for both domestic use and export.

Annual grey seal pup production has more than doubled since 1964. Productivity on individual islands is influenced by human activity. Total population size is estimated to have risen from around 10,000 in 1964 to around 20,000 in 1982 despite a management policy of culling originally intended to stop population growth. Grey seals tagged in Orkney have been recovered around most parts of the North Sea, Norway, the Faeroes and south to Ireland.

Considerably less is known about the biology of common seals in Orkney. A boat survey in 1979 counted 2653 adults and 420 pups.