The common strain A of the blight fungus (Phytophthora infestans) and two new strains, B and C, have been employed in testing potato varieties and seedling progenies, bred from the wild species S. demissum, for resistance to the disease. The reactions of seedlings to infection with strain C are compared with those of strains A and B. The C strain is shown to be more virulent than A, since it attacks some A resistant as well as all A susceptible plants. Likewise the B strain is more virulent than A. The difference between the pathogenicity of strains B and C, however, is not one of degree of virulence; one plant may be B resistant-C susceptible, while another may be B susceptible-C resistant. This difference is essentially of a qualitative nature. Resistance to these strains, which is manifested by the hypersensitive condition of the plant's cells, is produced in the presence of three major independent genes, Re, Rb and Rbc, which confer resistance to strains A and C, A and B, and A, B and C respectively. Segregations in each case are similar in type, and are characterised by an excess of recessive individuals.

Guanine-nucleotide regulatory binding proteins (G-proteins) serve to transduce information from agonist-bound receptor complexes to either effector enzymes or ion-channels. Drugs that perturb the function of G-proteins may do so by one of four mechanisms, (i) They may exert negative intrinsic activity toward the G-protein. For instance, we have shown that incubation of isolated plasma-membranes with the β-adrenoceptor blocking drug sotalol blocked both GTP-stimulated and isoprenaline-stimulated adenylyl cyclase. This suggests that the empty β-adrenoceptor is capable of tonically stimulating Gsα, and therefore adenylyl cyclase; that is, empty β-adrenoceptors promote GDP-GTP exchange, (ii) They may perturb the GDP-GTP exchange reaction. For instance, certain PDE inhibitors, including SKF 94836 and rolipram, stimulate a marked increase in the pertussis toxin-catalysed NAD+-dependent ADP-ribosylation of Giα. This effect is similar to that of GDP, which promotes stabilisation of the αβγ holomer of Gi. The effect of these PDE inhibitors is completely reversed by GppNHp, which triggers afly dissociation by binding to the guanine-nucleotide binding domain of the G-protein. PDE inhibitors may serve as a class of drugs which perturb GDP-GTP exchange, (iii) They may trigger uncoupling of receptor-G-protein complexes. For instance, the polycationic drug mastoparan binds to the C-terminal end of the G-protein and mimics the effect of receptor activation by promoting GTP-γ-S binding, a reduction in pertussis toxin-catalysed ADP-ribosylation, and inhibition of adenylyl cyclase activity. Other agents, such as polyanionic drugs, bind to the receptor to promote uncoupling of receptor-mediated activation of certain G-proteins. (iv) They may alter the cross-talk mechanisms that operate between different receptor signalling systems. For instance, protein kinase C promotes the phosphorylation and inactivation of Gi. This leads to an unopposed stimulation of adenylyl cyclase via Gs and, therefore, enhanced sensitivity to agents such as glucagon. Protein kinase C inhibitors may be usefully exploited to modulate these processes which appear to be abberant in certain disease states.

Sailing directions are one of the oldest aids to navigation that we know of in Europe [1]. Starting from the earliest, primitive descriptions of the courses (Octhere ca 800), the oldest sailing directions to Iceland/Greenland [2], and a brief description of the Bremen-Portulan fragment, from Jutland to the Holy Land (about 1200) [3], a long period covers the history of those descriptions of the courses, and information about routes for shipping in our latitudes.

Coppiced willow supports a much higher density of breeding birds than unmanaged more mature willow. This appears to be because it retains richer vegetation cover, especially in the herb layer, and so provides more breeding and feeding sites for both marsh and woodland birds.

Hydrocarbon analyses, using gas-liquid chromatography (GLC), have been conducted on benthic sediments from around the Beatrice A platform immediately after completion of the first well using low-toxicity oil-based drilling mud. These analyses, as expected, showed the major organic contaminant in the sediments to be fresh base oil from the drilling mud. It could be detected to a distance of 3 km from the platform in the direction of the prevailing currents.

A year later, after the completion of five additional wells using low-toxicity oil-based mud, a repeat survey showed the drilling mud base-oil could be detected in similar concentrations (by gravimetry) over the same spatial area. GLC analysis, however, showed that the base-oil had been severely biodegraded at many stations. The degree to which the n-alkanes had been biodegraded varied considerably between stations but appeared to be related to the distance from the platform and/or the total concentration of oil in the sediments. This has resulted in a discrete ring around the platform within which there was a rapid (and in many cases complete) loss of n-alkanes through biodegradation. Possible reasons for this phenomenon are discussed.

A provisional species list for the insects galling willow in Britain is presented. Aspects of willow biology which may be important in gall-insect species diversity are briefly discussed and the process of gall formation is reviewed for one species of willow-galling sawfly. An experiment investigating willow defences against galling, by measuring phenolic levels in plant and gall tissue, is also described.

Bracken is not a major weed problem on hill land in the north of Scotland, being restricted by environmental factors to the lower slopes of sheltered glens. There is no evidence of widespread stock poisoning by bracken in the area.

Ploughing and reclamation, forestry planting and spraying with the selective herbicide asulam have considerably reduced infestations of bracken on land worthy of improvement. At the present time there is little scope for further economic control of bracken.

Field experiments have defined full frond emergence from mid July to mid August as the most effective time for application of asulam. Reinfestation in about five years has been shown to follow incomplete control on small plots but an area sprayed by helicopter in 1972, where a very high degree of initial control was achieved, remained almost free of bracken in 1980.

Easier handling of stock and increased availability of summer grazing are reported following bracken control. An increase in herbage production has been measured experimentally in the second year after removal of the bracken by spraying.

In the Sanquhar district a bsain of relatively light Upper Carboniferous rocks (relative density 2·54) overlies a denser basement of Ordovician greywackes (relative density 2·72). A gravity survey over the area with coverage of approximately one station per square kilometre, increasing to a station spacing of 100 yards along certain traverses in critical localities, shows a close relation between the Bouguer anomalies and the known geology. A local gravity low over the Carboniferous outcrop is superimposed on a steep regional gradient decreasing south-eastwards. The trend of this gradient is parallel to the strike of the Ordovician rocks, but its exact relationship to the basement structure is not clear. The residual Bouguer anomalies reflect the structure of the Carboniferous rocks; in the south-eastern part of the basin they agree closely with the calculated effect produced by the known thicknesses, structure, and density contrast. Westwards from Kirkconnel, however, there is an increasing discrepancy between the observed and the theoretical anomalies, a discrepancy which indicates the presence of an additional mass of light rock concealed under the known Coal Measures. It is inferred that this material consists of older Carboniferous strata, thickest under the present-day valley of the Nith but concealed by overstep of the overlying Coal Measures against the flanks of the basin. These hidden rocks thin gradually to the south-east across a shallow monocline with north-east trend and south-east of Kirkconnel are truncated by a large fault trending east-north-east. Both the monocline and the fault appear to affect the Westphalian strata to a lesser degree than the base of the Carboniferous rocks.

The stratigraphical significance of the concealed strata is that they evince the existence of a pre-Westphalian basin, trending north-west-south-east, which antecedes the later Hercynian fold, and also suggest that pre-Hercynian movements took place along a fault, near Kirkconnel which, trends north-east-south-west across the basin.

The patterns of movements of indigenous and displaced trout (Salmo trutta) in a small loch were obtained by ultrasonic tracking techniques. Comparisons of these were made by developing stochastic simulations of their movements based on an analysis of the frequency distributions of step lengths, angles of turn and the percentage time spent actively swimming.

The dispersal and escape of displaced fish from an unfamiliar area of the loch can be explained principally in terms of random turning. Nose plugging appears to influence the distribution of the angles of turn without significantly altering the time taken to escape and return home.

Indigenous trout show a strong preference for turns of 180°, indicating a tendency to turn in their tracks. Although a simulation of the indigenous fish shows slower dispersion than displaced fish, it is insufficient to explain the containment of movement within a home range. It is probable that successive steps are not independent and there may be some association between step lengths and subsequent angles of turn. The implications of their autocorrelation are discussed.

The Clyde Estuary receives a relatively high pollutant load derived from the domestic and industrial wastes of half of Scotland's population. In order to monitor contaminant concentrations throughout the area, the Clyde River Purification Board (CRPB) initiated in 1980 an extensive ‘mussel-watch’ programme, having selected the common mussel as the most suitable indicator organism.

This 1980 survey served not only to identify shores with elevated trace metal concentrations and those which were relatively unpolluted, but also to assess changes in overall contamination of the area in comparison with previous surveys.

Following the success of the 1980 survey it has been gradually extended over the years, both in the number and geographical spread of sites visited, and in the substrates and determinands measured, as the CRPB's monitoring requirements have changed.

The 1984 CRPB ‘mussel-watch’ survey involved the collection of over 1200 mussels at twenty-four sites throughout the Firth of Clyde (Fig. 1), with subsequent determination of concentrations of the trace metals Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn, and of other toxic, persistent substances such as organochlorine pesticides and PCB residues.

Attention is focussed here on trace metal body burdens for Clyde mussels collected during the 1984survey.

A system is described which produces true-to-scale sonar maps of the sediment patterns on the seabed of the Continental Shelf waters. Correction is made for the speed of the ship over ground, and the 'drift angle' of the sonar beam during passage from one station to another. Work at sea has been extended to water depths of 250 metres, and the technique has been widely used for cable route surveys.

The physical and biological characteristics of a variety of sandy shores in Orkney are described using transect data from 7 sites within Scapa Flow and 7 sites from the Mainland and North Isles. Shore profiles are described and discussed, shores ranging in length from 80 m to 1200 m. Median grain size of the sediments was generally between 180 and 300 μm (fine to medium grade sands) and the sediments were very clean. The fauna was dominated numerically by polychaetes and amphipods on all shores, Pygospio elegans, Capitella capitata and Bathyporeia spp. being the dominant forms; molluscs were notably insignificant on most shores. Tables giving the maximum densities of every species recorded together with the maximum densities of dominant species at each station on all shores are presentThe results are compared with a range of North European shores which comprise basically similar communities but with much higher population densities in Orkney. A site of unique interest at the Bay of Quoys, Hoy, is described and discussed.

In 1968 the senior author discovered in a Boston, Massachusetts, bookstore a sketchbook of some 33 watercolours of the Challenger Expedition painted by Benjamin Shephard, a cooper assigned to the Challenger on November 15, 1872, at the age of 31. The paintings were all accomplished between the ship's departure from Gibraltar on January 26,1873, and the completion of her February 1874 work in the Antarctic before departing for Melbourne, Australia.

Shephard's paintings are elliptical in shape and measure 9·75 by 5·5 inches, each within a painted ‘frame’ resembling a leather belt with a ‘buckle’ at the lower left. The paintings themselves are skilfully done and each shows the Challenger at a different location during the voyage.

Since all but one of the paintings were dated by the artist, it has been possible to go back to the official narrative of the expedition and to the published logs kept by the Assistant Engineer, W. J. J. Spry, and by Sub-Lieutenant Lord George G. Campbell to determine just what was happening aboard at the time each painting was made. Excerpts from these logs provide the narrative accompanying the sketches which are to be published in book form to coincide with the Challenger Expedition Centenary celebrations. Black and white photographs of the sketchbook's cover and of four of the 33 sketches are included as part of this paper (Plates 1–5).

The basic principles of inheritance were not established as a consequence of an immense accumulation of descriptive evidence. In this respect, the history of genetics differs from that of many other branches of biology. Before Mendel's conceptual tour de force and indeed, until his rules of diploid inheritance were rediscovered at the turn of the century, the phenomenon of heredity remained a mystery. A number of plant hybridists grappled with the apparently inscrutable properties of variation and even Darwin, the most incisive and comprehensive thinker among nineteenth-century biologists, remained baffled. Nevertheless, in the space of some 80 years, a staggering explosion in our understanding of heredity and in the development of analytical techniques has propelled the science of genetics into the middle of the biological stage where it plays a role rather analogous to that of atomic physics vis-à-vis the physical sciences.

A brief description is given of the accident to the tanker Esso Bernicia that resulted in the release of 1174 tonnes of heavy fuel oil into the harbour at Sullom Voe. The measures taken to deal with the spill and the resulting oil pollution are described and their effectiveness assessed. Aspects of the environmental effects are considered with particular reference to birds, otters and sheep. Wide-ranging inquiries were made into the cause of the incident, the adequacy of the response, and the effects of the pollution. The actions that resulted are described. Finally the significance of the event is considered in relation to the subsequent development of oil spill contingency planning at Sullom Voe, and in the wider context of Shetland.

A historical review of the physical and chemical data collected from the Suez Canal waters in the first 40 years (1867–1906) during and after its filling shows that it was the focus of interest of many explorers and scientists. From 27 successive observations (table) the waters were completely analysed seven times. The salinity (density) was measured along the canal on eight occasions, of which four were not previously known. The first observations along the Canal were made in May 1870 by the Admiralty Ship Blue Cross. Her results, together with the second set of observations (February 1872), were found in a small booklet printed in Alexandria (Tissot 1872). The data of two sections (Durand-Claye 1875a; Anonymous 1907) were found by the author as unpublished manuscripts and are revealed here for the first time.

A comment on the determination of salinity of sea water by evaporation to dryness was found in a handwritten manuscript by Durand-Claye (1873). This comment was eliminated in the published text (Durand-Claye 1874), and is reproduced here for its interest to the history of chemical oceanography.

The difficulties in making a comparative study of these old data are explored. It is suggested to start some sort of ‘practical historical oceanography’ by studying old hydrometers, thermometers and other oceanographic apparatus using modern equipments in order to reassess the data of old expeditions.

The aims, methods and techniques of the macrobenthic monitoring programme in Sullom Voe and Orka Voe are described together with an analysis of the data obtained from surveys that began in 1978 and continue to the present. The distribution of the benthic macrofauna is discussed in relation to the sedimentological and hydrocarbon data obtained and compared with data from other Shetland waters. The macrofauna is considered to be typical of five of the six Facies used to describe the communities of the voes around Shetland. The possible effects of the terminal operations on the macrofauna are assessed and it is concluded that the disturbance noted to the macrofauna in Garths Voe, close to the diffuser at Calback Ness and in Orka Voe, essentially follows the same pattern seen in modifications to Shetland macrofauna that occurs where naturally occurring organic carbon enrichment exists.

Although common seals (Phoca vitulina L.) do occur in the Firth of Forth, the grey seal (Halichoerus grypus Fab.) is by far the most abundant species in the area. Some pups are born along the north shore of the outer firth but the vast majority are born on the Isle of May. This colony has increased in size from less than twenty-five pups in 1975 to more than 900 in 1986. Studies using conventional and radio tags indicate that many of the seals at the Isle of May originally came from the colony at the Farne Islands, off the Northumberland coast. Information from the Fame Islands population is used to predict future changes at the Isle of May. If current trends continue, more than 2000 pups could be born each year by the end of the century. However, it seems unlikely that this will occur. Management methods for controlling habitat damage are discussed.

A detailed consideration of the morphology, peritoneal and topographical relations, blood supply and certain aspects of the histology of the alimentary tube are considered in these two rare lemurines, the anatomy of which has hitherto been very incompletely known. Evidence is presented of the structural apartness of Hapalemur from Lepilemur and Lemur and therefore for its separation in a separate subfamily of Lemuridæ. Differences between Hapalemur and Lepilemur are seen in the stomach, cæcum, colon, spleen, liver and gall-bladder. The resemblance of the spleen of Hapalemur to that of the marsupials proclaims its primitive status, while the fissuration and relative sizes of the main hepatic lobes show noteworthy differences in the two genera. In some respects Hapalemur approaches the Cheirogaleinæ, but cannot be included by definition within that subfamily.

Determinations of dissolved oxygen and nutrients in the water overlying the sediments, of sedimentation rates, and of redox values, acidity, dissolved sulphide, carbon, nitrogen and cellulose values at different levels in the sediments themselves have been carried out in various parts of Sullom Voe. The effects of oxygen depletion following intermittent stagnation of the bottom water in the inner basin on carbon cycling in the sediments are discussed and contrasted with the chemistry of oxygen-rich sediments elsewhere in the voe.