Previous reports (Black, 1943, 1945) on the resistance of potatoes to the blight fungus (Phytophthora infestans) have shown the existence of at least two major genetic factors (Ra and Rb) in the host, and the occurrence of not less than two strains (A and B) of the pathogen.

From the studies then reported, it was concluded that the two genes had been brought into the potato from different phyletic sources and that one, Ra, when in the dominant state, conferred resistance to strain A, while similarly Rb conferred resistance to strain B.

In studying the literature relating to that little-known prosimian, the Angwántibo—with a view to incorporating the main facts known about it in a comprehensive work on primate anatomy at present in preparation—I had occasion to consult the original description of the species by J. A. Smith (1860). I there discovered that the type was a spirit specimen (an “adult” male) which was received in Edinburgh, along with a second male, from Old Calabar. There is some confusion in the literature as to the fate of these specimens and this should, I think, be cleared up. Both specimens were procured in 1859 by Rev. A. Robb, one being sent, indirectly, to Smith and the other to Andrew Murray. Smith recognized in his specimen something new and accordingly described it as a new species of Potto, placing it in Bennett's genus Perodicticus as P. calabarensis. He gave an assurance of his intention of depositing the type in the Natural History Museum of the University of Edinburgh, but later sent it to his friend Carruthers at the British Museum for comparison with Bennett's type of Perodicticus potto. Some useful observations were made upon it by Carruthers and incorporated as an addendum to Smith's paper. The specimen was evidently returned to Edinburgh and found its way to the University, but in 1860 it was transferred, with other material, to the Edinburgh Industrial Museum (since 1904 the Royal Scottish Museum).

With the kind assistance of Professor J. Ritchie I have succeeded in tracing it, and with the permission of Dr D. A. Allan, Director of the Museum, and the helpful co-operation of Dr A. C. Stephen, Keeper of Natural History, I have had the privilege of studying it.

The Clyde Estuary is recovering from gross pollution inherited from the age of the Industrial Revolution.It is necessary now to establish the degree of recovery and determine any subsequent effects of future planning consents. Documentation on water quality was subjective until the 1960's when quantitative studies on pollution levels commenced.

Much attention has been paid to dissolved oxygen (DO) levels in the estuary. The changes in the DO regime over the last ten years have been quantified with the help of multiple regression techniques. The use of these techniques in establishing the changes resulting from improvements to Dalmarnock and Paisley sewage treatment works is described. Deterministic models, based on the diffusion-convection equation, have been used to predict future DO conditions. The theoretical base of these models is outlined and examples are given of the use of the models in predicting the effects of possible developments on the estuary.

Biological monitoring has also been utilised to assess estuarine recovery. Benthic data has been accumulated since 1967. Regular surveys highlight improvements in species richness, diversity and stability. Spatial and temporal population variation was investigated and the salinity tolerances of the species considered. Fish life is increasing and is now present for much of the year, although salmon are still excluded from the upper Clyde system. The lower estuary remains an important overwintering feeding ground for wader populations.

The Firth of Forth, in terms of physical oceanography, is part of the North Sea. The general circulation pattern in the firth must be regarded as largely speculative. There have been insufficient measurements of insufficient quality, and what evidence exists leads to the view that what circulation there is, is sluggish and varies from season to season and from year to year.

A description is given of the three principal mechanisms that contribute to circulation. Tides, due initially to astronomical forces, manifest themselves in the Firth of Forth through the rise and fall of the adjacent open sea. This rise and fall, periodic in mid ocean, is no longer strictly so in the firth and neither are the tidal currents. The wind-driven currents in the sea are influenced by the earth's rotation. In the Firth of Forth, some of this influence is retained. Naturally, wind-driven currents are larger near the surface. Finally, when water of different densities meets, overturning causes convection currents. All of these effects are present to some extent in the Firth of Forth. In addition, specific account has to be taken of complicated coastal and bottom topography and river outflow. Some attempt to bring together these effects and available measurements is made in this paper. Lastly, several theoretical models are proposed which account for the magnitudes and directions of the observed steady circulation. Mathematical details are given in appendices.

According to Borst (1913) each individual should be regarded as a specific biochemical system, and within this common background the different organs and tissues work together whilst preserving their own characteristics. On such a foundation, strengthened by the results of his own extensive experiments, Loeb (1930,1945) has built up his conception of the biological basis of individuality. According to his thesis the individuality of a tissue is a summation and integration of qualities in respect of its identity as a particular tissue or organ, in respect of the organism of which it is a part, and in respect of the species and order of this organism. The autograft is attuned to the biochemical system of the organism and is therefore accepted as a transplant, but the host reacts to the homograft (and more so to the heterograft) and makes an effort to destroy it. While the extent of the host reaction depends on many factors—e.g. genetical relationship, age of host and donor, etc.—the ability of different organs and tissues to survive as homografts varies considerably. It is, for example, well known that homografts of cartilage and cornea survive within the host long after homografts of other tissues and organs have been destroyed.

To regard the more prolonged survival of homografts of cartilage and cornea as evidence of low tissue specificity (Loeb, 1930, 1945) still leaves undetermined the real reason why these particular tissues are less readily overwhelmed by those of the host.

An account was previously given of the discovery of two cases of placental fusion in mice, and it was suggested that this condition might occur fairly frequently. This has been amply borne out by subsequent experience, as fourteen other examples have been found while working with mice, and in addition it has once been found in the rat. From this additional material further information about the types of developmental abnormalities that may result from this condition has been gathered. Since the last paper, Owen (1945) has found that commingling of the fœtal circulations in cattle twins can result in the transfer of erythrocyte precursors between partners, resulting in animals exhibiting blood-groups bearing no relation to their genotype. Similar transfers in mice would lead to confusion in many genetic experiments, especially in transplantation experiments with tumours.

No genetical basis for the condition is apparent from the data available. It has been, noted in three matings of CBA mice, two of C3H mice, eight C3♂ × CBA♀, and three stock mice, the proportions being roughly related to the relative numbers of each type examined at the time of littering. The frequency is rather less than 1 per cent, of all placentas seen. The only common feature, to which attention was also drawn in the previous paper, has been that the fusion occurred always in conditions of uterine crowding due to large litter size. The smallest litter size in which this fusion was found was five, but in this case five placentas were present in one horn. Whenever labour was observed, it appeared to be difficult and prolonged. Once, by good fortune, delivery was timed approximately. A CBA mouse was found to have delivered two young, and two more were born within the next ten minutes. Nothing further appeared for two hours and ten minutes, when a live pair with fused placentas was delivered with some distress. The last two of the litter, making eight in all, were delivered within twenty minutes of the completion of the birth of the fused pair

The cutaneous reactions induced in the skin of human volunteers by protein A from Staphylococcus aureus have been studied. This cell wall protein induces no response when applied in solution to intact skin. In contrast a vigorous inflammatory reaction is seen if it is injected intradermally or applied to skin from which the stratum corneum has been partially removed. This study demonstrates that the intact epidermis is an important protection against this microbial product.

Human skin propionibacteria have been shown to produce, in vitro, a wide range of inhibitory substances including bacteriocins, bacteriolytic enzymes, bacteriophages and low molecular weight metabolites (e.g. ammonia, propionic acid). Some or all of these substances may play a role in the ecology of cutaneous populations of micro-organisms and may be involved in maintaining the balance of the normal flora. There is no evidence to suggest that they deter or exclude other transient bacteria including pathogens. Similarly, evidence in support of the in vivo production of growth inhibitors by propionibacteria with activity against other skin micro-organisms is lacking (except for bacteriophage and propionic acid) so that their potential role in controlling cutaneous populations must be interpreted with caution.

Regular moulting can prevent colonisation of the skin surface by epibionts, although some invading organisms are sufficiently mobile to overcome this protective device. Bacteria and sessile protozoans settle on the surface of the claws of Xenopus, where the keratinised cells are not shed as regularly as on the skin. Alternatively, parasites may inhabit the orifices, which also are not affected by moulting.

The Outer Hebrides, because of their apparent isolation, attracted zoologists in the past who looked for new species and subspecies and some sought to explain the origin of the invertebrate fauna by exotic land connections in preglacial times. These expectations were largely unfulfilled and the speculations are unsupported by geologists or geomorphologists. The non-marine invertebrate fauna is examined from published records, museum collections and special field surveys and the lists total over 2500 species, of which approximately one-third are of general occurrence in the Outer Hebrides. Three species of mites are new to the British fauna and over 700 species, mainly insects, are additions to the Hebridean fauna. The fauna is impoverished compared with the mainland and this may be due to climate and the lack of variety of habitats and the low structure of the vegetative cover. Upland species occur on the moors and some descend to sea level, possibly on account of the low mean temperature in summer. Species with a north western distribution occur in the Odonata, Hemiptera, Lepidoptera, Hymenoptera and Diptera. Species with a discontinuous distribution are discussed and it is suggested that some reached the islands by natural means and others by human agency and there is no evidence of refugia for a glacial relict fauna. Examples are given of insects with a south western distribution arriving by sea in driftwood and five amphiatlantic species, including a freshwater sponge, which may have been brought by migrating birds, a wrack-fly, two strand-line beetles and a mite, which may have been distributed by the Gulf Stream and the North Atlantic Drift.

There are no endemic species, but a few so-called subspecies of insects may be restricted to the Outer Hebrides. Changes in the fauna are traceable in a stratified Flandrian shell deposit in Harris, where two species have become extinct, and some insects have also become extinct in St Kilda during the last century. Some of the most conspicuous land snails have arrived in historic times and the most rapid coloniser has been a brackish-water snail which has spread throughout the islands since 1933.

The adoption of emerging biotechnological methods in plant breeding is presented discussing specifically the relevance of cell genetics to potato improvement. The finding and use of efficient anther plant producing strains of potato (EAPP clones) is first discussed. This is followed by the presentation of recent progress toward the obtaining of diploid potato strains producing a high percentage of monohaploids from anthers. The selection of homozygous diploid regenerants (potato ‘pure lines’) by using an RFLP approach is also presented. A summary chart is presented, containing the description of an integrated breeding procedure that may be considered for future breeding of this species.

For a full decade, the Office of Naval Research (ONR) led the United States into the development of science by research contract. Marine geophysics and oceanography were a part of this, as were the solid earth sciences and meteorology.

By 1950, ONR was firmly established, World War II seemed far behind, and oceanographers in the United States were enthusiastically looking forward to what turned out to be ten years of their most productive work. By combining oceanographic talent and ONR funds and logistics, there was created one of the most effective systems yet invented for accomplishing science and technology at sea.

New institutions were established, old institutions revived, fleets were designed, deep diving initiated, ocean monitoring begun, Arctic oceanography started, expeditions mounted, and discoveries made which, when coupled with other knowledge, were to contribute to far-reaching consequences for the earth sciences and how we now view our geophysically active planet.

The oceanographers will speak for themselves. This paper presents only the view from Washington at the time, and how at least some of the activity there helped to make possible the Great Decade of Oceanographic Development, 1950–59.

The long history of discharge of industrial and domestic waste to the Forth makes the area of particular interest to environmental scientists. The area has been studied both in its own right for the monitoring and control of contamination by trace metals and organohalogen compounds, and in the study of processes which influence the dispersion and effects of these substances. This paper discusses the inputs of contaminants to the area, their occurrence in the water, sediments and biota, and places the Forth in context with other coastal areas of Scotland. The paucity of information concerning organohalogen compounds is contrasted with the extensive work carried out on trace metals.

Oestrogen regulates the growth of human breast cancer cell lines ZR-75–1, T-47-D and MCF-7 (KO and McGrath). Basal cell growth can be reduced (T-47-D) or eliminated (ZR-75–1) by prior growth in the absence of steroid and phenol red for three weeks, demonstrating that oestrogens can have long-lasting effects on cells in culture (termed “steroid memory”). Effects of oestradiol on different cell biological parameters are described and interaction with other steroids and serum growth factors is discussed. Antioestrogen action in these cell lines is affected by at least five parameters: (1) presence of phenol red, (2) time in culture, (3) cell density, (4) antioestrogen concentration, (5) steroid memory.

An in vitro model for loss of oestrogen sensitivity in breast cancer is presented. Both dependent (ZR-75–1) and responsive (T-47-D) cells lose oestrogen sensitivity when deprived of steroid in the long term but show a gradual increase in growth. For ZR-75–1 cells, the effects appear to be clonal but occur at a high frequency (about 1 in 1,000 cells). Parallel alterations in sensitivity to other steroids, antioestrogens and serum growth factors are shown. Molecular markers of this action are described and the results compared with the well-established model for loss of androgen/glucocorticoid sensitivity in SI 15 cells.

Isolates of the tropical fungus Crinipellis perniciosa obtained from cocoa and lianas in Ecuador were grown on media ranging from −0.45 MPa to −9.0 MPa water potential and their responses compared to those of other agarics and Xylaria species isolated from cocoa. Antagonism between mycelia of C. perniciosa and these isolates was also assessed over the same range of water potentials. It is hypothesised that C. perniciosa and other canopy inhabiting fungi of tropical forests are adapted to water stress, but are not competitive with fungi which colonise later, following litterfall, from lower litter and soil horizons, where water availability is higher. Xylaria spp. proved to be aggressive antagonists of C. perniciosa over a range of water potentials.

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.

Sands are sorted by the actions of air and water. A mathematical–physical model for the ensuing spatial and temporal variations in the size distributions of the sand grains is outlined. A crucial element in aeolian sorting and transport of sand is the process that takes place when a saltating grain impinges on the sand surface. This raises the problem of describing the texture of sand surfaces. Some initial empirical and mathematical findings concerning this problem are discussed. A closely connected question is that of how the grains in a sand deposit are packed and how this relates to the size distribution. Voronoi tesselations in combination with random point processes seem to offer one useful approach to the question.

Typical phytopathological defence reactions of tobacco have been studied in response to ozone. After a single standard ozone pulse (5 h, 150 nl 1−1) β-l,3-glucanase was induced up to 40-fold in the sensitive tobacco cv. Bel W3, which developed necrotic lesions following the treatment. The activity was elevated 10-fold in the tolerant Bel B without concomitant injury. A decrease within 24 h occurred only in Bel B. Tyramine hydroxycinnamoyl-CoA transferase activity was induced 6- to 7-fold in both cultivars with a maximum after 5–8 h. Tyramine conjugates as the product of this reaction could not be isolated and were apparently rapidly integrated into the cell wall. Precultivation of Bel B plants in a greenhouse containing up to 70% of the outdoor ozone concentration resulted in a 4-fold induction of β-l,3-glucanase and a further increase after an administered ozone pulse. Pretreatment (30 nl 1−1 ozone, 7 h per day, 23 days) of sensitive Bel W3 caused increased injury and ethylene formation upon a subsequent ozone pulse. β-l,3-glucanase was induced to the same level as in non-pretreated control plants. In a comparison with other major air pollutants (SO2, NO2), only ozone induced the above reactions. However, a combined treatment of ozone and NO2 led to synergistic effects. These data indicate that ambient ozone is able to change the phytopathological disposition of plants. This finding may have practical significance for the usual plant experiments carried out in greenhouses with non-filtered air.

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.

The Shetland Islands lie between latitudes of approximately 60° and 61° North, over 100 miles north of the Scottish mainland. They are influenced by the North Atlantic Drift so that the climatic conditions are much less severe than for other land masses, for example in Southern Greenland where the mean temperature for five months of the year is below freezing. The environment in all its considerable heterogeneity is well described in The Natural Environment of Shetland (Goodier 1974) and in The Natural History of Shetland (Berry & Johnston 1980). Briefly the islands lie on the western oceanic fringe of Europe, have approximately 1450 kilometres of coastline and an area of 1468 square kilometres. The geology is varied and geomorphologically the islands constitute a drowned range of glaciated hills situated on the continental shelf. The coast consists of extensive areas of cliffs and voes with relatively few beaches. In general, the ‘outer’ coasts, especially on the west, are exposed high energy environments. In contrast, the inner coasts, often voes, are deep sheltered inlets. The land itself tends to be hilly and, where it has not been stripped for agricultural use, is blanketed with peat, with the main vegetation heather (Calluna vulgaris) and cotton sedge (Eriophorum angustifolium). Approximately 10% of the land is covered by rushy vegetation and there is very little relict scrub though there are one or two planted woodland plots. The original scrub was largely eradicated by man who arrived in Shetland from Iberia about 3500 BC. Colonisers from Scandinavia arrived in the eighth century and have had a lasting influence on the culture of the islands. In 1971 the human population was about 17327 and in 1989 was 23 214 (SIC 1992).