Robert Burns’ poem ‘My Heart's in the Highlands’ confirms that deer have been an important element of the Scottish Highlands for many years. But, what is distinctive about them? They can be separated from other vertebrates by an array of characteristic features including the absence of a gall-bladder, the doubling of the lachrymal orifice and the development of deciduous bony outgrowths of the frontal base of the skull—the antlers. In his paper, Lincoln discusses the shedding and regeneration of antlers with associated spring minimal, and autumn maximal, concentrations of testerone. He also describes how, in most young stags, antler formation will proceed unaided with successive annual developments being triggered by a healing response to the wound formed when the old antlers are cast. In other congenitally antler-less stags (hummels), it seems that antler formation can be induced in perpetuity by wounding antler pedicels, each of a pair needing to be damaged separately.

The garden chafer. Phyllopertha horticola (L.), renews its population every June. Its numbers fluctuate irregularly from year to year. During 1947 75 in the English Lake District, it had two ‘outbreaks’ (with peaks in 1952 and 1975) separated by a long period of low population (1956–70). In nine of the years 1948 75, October population increased significantly over that of the preceding year: in eleven, it did not change significantly; and in ihe remaining eight, it decreased significantly. These fluctuations in numbers were due to fluctuations in the effective environmental factors (weather, enemies and intraspecific competition) influencing sun ival, fecundity and migration. Weather was more effective than enemies in this respect and intraspecific competition became important only when weather and enemies together failed to keep numbers from rising dangerously high for the chafer. Weather was, of course, density-independent in action. Among enemies, interspecific competitors were density-independent while pathogens, parasites and predators were all imperfectly density-dependent. The only perfectly density-dependent factor was intraspecific competition. These findings bear out Milne's theory (1957a et seq.) that for part of the time, natural control of population increase of any species X is due to the combined action of density-independent and imperfectly density-dependent environmental factors but, whenever this combined action fails (as inevitably it sometimes must), increase to the point of collective suicide is prevented by the one and only perfectly density-dependent factor, namely, intraspecific competition of X; on the other hand, decrease of numbers of X to zero is prevented ultimately by density-independent factors alone.

In the late eighteenth century the Scottish Highlands were attractive to travellers eager to test themselves against climatic, dietetic and other deprivations. From the early nineteenth century, the Scots themselves became more adventurous and Scottish medical men, notably Mungo Park and David Livingstone, played a prominent part in the exploration of Africa. In the 1860s Livingstone's prolonged travels through the Dark Continent and his belief that he had conquered malarial fever led to the dispatch of the first Christian Mission to the Zambesi region, a venture which failed largely as a result of the missionaries' ignorance of hygiene and medicine.

The establishment of the European presence in British Central Africa (now Malawi) was accomplished by representatives of the Scottish Presbyterian Churches in the 1870s. This paper examines some of the problems encountered during the ensuing half century. Specific themes include the impact of developments in transport systems; housing and sanitation; hints on suitable clothing; the presence of trained medical personnel in both Mission and Government and their role in the study of tropical disease; use and abuse of alcohol.

The evolutionary origins and relationships of deer are briefly reviewed, with special reference to the species currently living wild or feral in Britain. Two species (red and roe) are native to this country; a third (fallow) was previously native but has been re-introduced from continental Europe; and three taxa (sika, muntjac and Chinese water-deer) have been introduced from eastern Asia. The Pleistocene history of red, roe and fallow deer in Europe is traced in detail, with emphasis on changing patterns of distribution and the climatic and vegetational conditions associated with fossil occurrences. Comparison of Pleistocene habitats with those occupied at the present day helps in an understanding of the ecological flexibility and rangelimiting factors of each species. The taxonomic status and habitats of the Asian species in Britain, as compared to their countries of origin, are briefly reviewed, and the dates of introduction into Britain of the Asian species and of fallow deer are discussed.

Red deer are now being farmed for meal production on an intensive scale. They are manageable, adaptable and healthy animals, and. with care and good nutrition, they become far more productive than wild deer.

Their digestive efficiency resembles that of sheep. Productive activities caking and lactation, fattening and antler growth occur in summer when food is plentiful and depend on endocrine and metabolic cycles entrained by day length. Dietary energy needs of deer are similar to those of cattle but higher than those of sheep: however, because young deer store little fat, they produce lean meat as efficiently as sheep.

Deer produce rich milk: the growth of sucking calves reflects the supply of nutrients available to their dams. In winter, calves benefit from shelter: nonetheless, their growth and appetite decline, even when day length is experimentally lengthened. While good nutrition improves winter growth, this is costly: furthermore, improved winter growth is followed by somewhat poorer growth during the succeeding summer. Slaughter of calves at 6 months of age rather than 16 months may allow greater efficiency of meat production.

Deer carry 50%more muscle than sheep, much of it in their well-priced haunch. Cahes deposit little fat until half grown: adults lose their summer fat during the rut and winter. The lean character of venison well matches modern consumer requirements.

The speed and frequency of modern travel has brought problems to the traveller that were less obvious in more leisurely days; these are both of an infectious and non-infectious nature and especially relevant to travel in tropical and subtropical areas.

Not everyone is at ease with air travel and travel sickness, anxiety, fatigue, and jet lag are experienced by many; sudden arrival in a new environment means adjustment to differences in heat, humidity and diet.

Infectious diseases are more prevalent in many hot countries and fall into three broad groups: (a) those where fever predominates, (b) where diarrhoea is the main feature, and (c) a miscellaneous group.

(a) Malaria, enteric fever, trypanosomiasis, leishmaniasis, typhus fever, brucellosis and a wide range of viral infections.

(b) Diarrhoea may vary from relatively mild travellers' diarrhoea to more serious dysentery. Other infections include cholera, salmonellosis, schistosomiasis and infections due to vibrios, protozoa and helminths.

(c) Miscellaneous infections include rabies, poliomyelitis, hepatitis and the sexually transmitted diseases.

To fully appreciate overseas travel the traveller must adopt sensible precautions before, during and after his journey. Practitioners must become familiar with the possibility of exotic illness and both under-graduate and post-graduate training take them into account.

The occurrence of an outbreak of Legionnaires' Disease among members of a package tour who had stayed in Benidorm, Spain, in 1973 gave an insight into some of the hazards encountered by tourists abroad.

Subsequent surveys of travellers returning to Scotland have been carried out and of 2,211 persons questioned 43% had been ill during their stay abroad or shortly after return. Package holidaymakers reported most symptoms and university personnel least. Alimentary disorders accounted for the majority of illnesses but respiratory difficulties were recorded by 16% of those who were ill. Tourists to North Africa were particularly affected. Most attributed their illnesses to problems associated with food, drink or excessive sunbathing.

The mechanism involved in the control of antler growth was studied in three experiments using red deer living at Reedie Hill Deer Farm in Fife. Scotland. Observations were made on three congenitally polled stags (hummels) captured from the wild, one female red deer (hind) induced to grow antlers by treatment with testosterone, and four castrated stags (havicrs). The overall results support the view that in the stag it is the increase in secretion of testosterone by the testes at puberty which stimulates the initial development of the antler pedicles, and it is the subsequent seasonal cycle in the secretion of testosterone which dictates the seasonal casting and regeneration of the antlers. The high blood levels of testosterone in the autumn cause the calcification and death of the antler tissue, and also prevent the process of rejection of this tissue for the remainder of the breeding season. The dead antlers can thus act as an insensitive fighting weapon when rival stags compete for access to females during the rut. When the testes become fully regressed in spring, it is the withdrawal of testosterone which allows the old antlers to be cast off. and the wound on the surface of the antler pedicles triggers the regeneration of new antlers. In hummel stags which have failed to complete the initial growth of the antler pedicles, it is possible to trigger the development of antler tissue by wounding the rudimentary pedicle, and once this tisue has formed it is cast and regrown annually due to the seasonal evele in the activity of the testes.

Malignant catarrhal fever (MCF) is reviewed and recent findings described. It is defined as a fatal disease which affects many species of Bovidae and Cervidae, characterized by widespread necrosis and lymphoid cell proliferation and can be caused by at least two infectious agents. In Africa, a herpesvirus which infects its natural host, the wildebeest, without obvious symptoms causes substantial losses in cattle due to MCF. Elsewhere, the cause of MCF is unknown but circumstantial evidence implicates sheep as the source of infection. While cattle are infected only sporadically with this “sheep-associated” form ol disease, infection of farmed deer is common, representing the most serious disease threat to the industry.

It is considered that infection of sheep and wildebeest with their respective agents operates to their advantage, causing no disease in their natural host, while transmission to other ungulates has fatal consequences, eliminating these potentially competitive species.

Recent studies of the disease in deer and the transmission of MCF from deer to rabbits are described. The evidence suggests that the disease process involves a novel dysfunction of the immune system which results in a massive lymphoid proliferation and an atopic allergic response. It is considered that similar processes may also be involved as a component of other diseases of man and animals.

All travellers have recourse to food and drink either while journeying or having arrived. Either way they represent problems of quality control to caterers as any deterioration in standards can have serious effects on travellers' physical and mental well-being, albeit in the short term. The rapid expansion of travel in the last few years, which is unlikely to diminish, has probably improved standards of hygiene and nutrition as a whole but not without some curious side effects. Despite all the years of study and effort put into food hygiene in many countries, most travellers to a foreign state can still expect an upset stomach within a few days of arrival. The main problem for caterer and customer alike is the provision of safe food so this paper deals with the problems encountered in ensuring that travellers have ready and universal access to wholesome meals. In many cases satisfactory sources of supply, methods of preparation and staff training have been evolved so the problem is not of establishing standards but of ensuring continuity and development, especially in times of economic recession or after the first flush of enthusiasm has evaporated. Also considered is the problem of matching strangers demands for ‘native’ food with what they will actually eat, plus the problem of producing safe food which retains some of the original flavours, aroma and effects.

Diarrhoea caused by intestinal infections is the commonest symptom affecting travellers particularly those from developed countries with temperate climates who are visiting less advanced countries in tropical and subtropical parts of the world. It can be troublesome, embarrassing and sometimes incapacitating and has spoiled many holidays.

The infections are almost invariably contracted from food or water although the primary source is usually man, frequently a food handler who is a faecal carrier of one or more pathogenic organisms and whose personal hygiene is inadequate. In many tropical countries human faeces (‘night soil’) is used to fertilise crops especially vegetables such as lettuce and if these are eaten uncooked or unwashed intestinal infection may result.

Infective diarrhoea in travellers may be caused by bacteria, viruses or certain protozoal organisms. Bacterial aetiological agents include Salmonellae, Shigellae, Vibrio cholerae and also certain strains of Escherichia coli which are capable of producing enterotoxins. These enterotoxins are potent causes of diarrhoea in travellers. Recently recognised as a bacterial cause of intestinal infection in travellers are campylobacter species. The protozoa which cause travellers' diarrhoea are Entamoeba histolytica and Giardia lamblia, the latter organisms being a common cause of chronic diarrhoea in recent travellers. A number of recently recognised viruses have been associated with diarrhoea in travellers, the most notable being rotaviruses.

The above micro-organism;, cause disease in the intestinal tract by different pathogenic mechanisms which are described in this paper.

The prevention of travellers' diarrhoea, especially the use of chemoprophylaxis, is a controversial topic which is discussed.

It has been estimated that approaching one thousand million people will travel annually on commercial airlines by the end of the present decade. Many will be transported to tropical and subtropical countries and it is, therefore, an opportune time to consider the present topic.

In the red deer population of the Isle of Rhum, the effects of increasing population density on reproduction and survival vary with the individual's sex, age. reproductive status, home-range quality, group size and social rank. Males are generally more strongly influenced than females. Within both sexes, individuals that are at an initial competitive disadvantage are generally most strongly influenced by rising density.

These differences are likeh to have far-reaching consequences. In particular, they may help to explain why dense deer populations commonly have female biased adult sex ratios: why calculations of maximum sustainable yield commonh overestimate the number of animals that can be culled; and why some populations that are not subiect to animal or human predation stabilize while others oscillate.

The traveller requires an easy guide to the important preventive measures for the common ailments that may be acquired on journeys. The card described is useful for this purpose.

Documented studies of the ecology of red deer in Scotland refer principally to populations which occupy treeless moorlands. Commercial forests have become a major part of the Scottish landscape and little is known of the dynamics of the red deer populations which inhabit them.

Red deer which benefit from the enhanced shelter and nutrition of a woodland habitat often perform better than those occupying open-range. Birth rates of 60–70 calves 100 hinds are common, especially in forests in the south and west of Scotland. This potential may be reduced to a post-winter recruitment of 50 60 calves 100 hinds (cf. birth rates on open-range of 40 60 calves 100 hinds reducing to 30–35). A range of densities in forests of 5–15 deer km" is almost identical to the densities found on open-range.

Simulation models suggest that many woodland populations can support a sustained yield of about 20% of adults each year and focus attention on the practical difficulties of achieving culls in commercial forests. Simulations of changes in forest structure are used to demonstrate the related changes occurring in the ability of the habitat to support changing densities of deer through time.

In a study in Galloway, southern Scotland, evidence suggests that the red deer population has increased considerably during the expansion of commercial forestry between 1960–80.

The study began in 1978 at Glenbranter Forest, Argyll. Use of habitat by red and roe deer was measured from the accumulation of pellet groups and from observations. Approximately 2000 trees less than 9 years old and 6000 older ones were monitored for damage and response.

Habitats in areas dominated by heather in or close to the forest were the most occupied by both species and pole-stage crops the least. However, most dung was found on the extensive areas of recently planted ground. Roe deer were relatively more abundant than red deer in stands of 9 to 15 year-old trees.

In summer, red deer ate mainly grasses and roe mainly forbs. In winter, these preferences remained, but Calluna became more important to both.

Browsing on leaders was heaviest in winter and May–June. Approximately 50% of leaders on trees less than 6 years old were browsed annually. Most trees regained leaders within 12 months, many becoming multi-stemmed. Of the trees. 1% were bark-stripped per annum. In older stands the smaller trees were most damaged, in younger stands the larger trees.

The most important disease for the traveller to avoid and for physicians to suspect in travellers is malaria. All tropical Africa and most tropical areas in the East and Far East are now malarious. The infection has returned in recent years to India and several other parts of the East and Far East from which it had been almost eradicated. Travellers to those regions should, therefore, take appropriate malarial prophylactics and malaria should be the cause first suspected among those with fever who have recently visited malarious areas. The emergence of malarial strains resistant to chloroquine poses problems both for prophylaxis and treatment of the established disease.

The recognition in 1969 of Lassa fever has introduced a new problem in managing those with fever who have been to West Africa within the preceding three weeks.

Travellers to game parks in Africa have greatly increased in number within the last decade and are exposed to trypanosomiasis. Several cases resulting from such exposure are known. They cause special diagnostic problems.

Hepatic amoebiasis may be unsuspected until a considerable amount of pus has collected and the risk of complications developed. Its clinical features need to be borne in mind.

Helminthic infections are ubiquitous in the tropics. Schistosomiasis, ascariasis and strongyloidiasis are of special importance and practitioners in developed countries need to be familiar with their characteristics.

Awareness of the possible presence of tropical infections is the keynote to success both in avoiding them and in managing them among those whose precautions have been deficient.

The pleasure of a holiday in warmer and sunnier climates can be increased by ensuring graduated exposure to the sun. Suitable measures can avoid the inflammatory reaction of sunburn in the short term and also be of benefit to the individual in the long term.