PART FIVE: TECHNOLOGY AND SOCIETY 792 The pastoralist whose diet is dependent on the milk products from the flock or herd is perhaps the most precariously balanced exploiter of marginal areas, since lactation is so dependent on adequate food and water supply. Left to its own devices, it is likely that a human population density will be established which reflects the carrying capacity of the land and the territory in which the shepherd or cattle herder moves. There may be occasional short-term weather changes which cause distress to a community, but in general these effects would be local, and can be survived because the stocking rate would originally be well below the level supportable within that area. Unfortunately it is only in more recent times that western agencies have recognized the significance of the low stocking rates in terms of a safety net, and that the placing of wells, and therefore water, into areas that had previously been without, admittedly increases the carrying capacity of the land, but only by making the fall-back area unavailable in bad times. The actual process of removing milk from the animal changed little from the earliest times until well into the twentieth century. Selective breeding has greatly increased the yield from any one animal, but while farm labour remained relatively cheap, there was little incentive to look for alternatives to hand milking. Although some experiments on vacuum milking machines had been carried out in Britain and America in the 1860s, it was not until Murchland’s patent in 1889 that a practical machine was developed (Figure 16.5). However, the continuous pressure of this machine caused damage to the sensitive udder tissues and it needed Dr Shield’s pulsating mechanism to realize the full potential of the idea. Even then hand milking was a continued practice in much of Europe until the middle of the present century. The very perishable nature of milk limited the ways in which it could be exploited in increasingly urban societies. Town dairies allowed a certain volume to reach a broader market, and the farms on the edges of smaller towns were able to supply them with fresh products. Processing into cheese or butter increased the ability of the product to travel, but it was not until the coming of the railways that the major markets could be reached. Not long afterwards the development of refrigeration (see p. 796) again changed the market structures dramatically, since now countries as far away as Australia and New Zealand were able to supply Europe with the perishable dairy products they were so well suited to produce. These changes in transport provided the stimulus for the development of more sophisticated mechanical means for milk separation and churning which were to occur in the late nineteenth century. Improvements in road transport also extended the ability of farmers to get liquid milk to the railway, or at least to a central collecting point, and as this occurred so the production of butter and cheese on the farm gave way to the factory-based system of today. These outside influences, together with the increasing decline in labour willing to work long and often antisocial hours, has in turn created an increasingly mechanized and automated cowshed. AGRICULTURE 793 The early milking machines consisted of a bucket attached to a pump which created the vacuum in it. From the bucket ran a length of rubber piping to which the ‘cluster’ was attached. This cluster consisted of four carefully designed cups which acted to simulate the calf’s sucking action so as to stimulate the lactating animal to release her milk. The vacuum is not intended to actually suck the milk from the animal, but rather to carry the milk away once it has been released. For the cowshed the vacuum is supplied by a pipeline running along the shed in such a way that the bucket could be connected at different points along its length. As each cow was milked the bucket was carried to the dairy where the milk was cooled and placed in churns ready for transport. In modern machines the cluster still exists, but the milk now passes down pipelines directly to storage tanks where it is cooled, and from which it is directly collected. Milk in its liquid form is the most perishable of agricultural products, and for any economy that is dependent on it for a large part of its diet, there must exist the ability to process it into a storable form. There are many ways in which liquid milk may be treated to prolong its usefulness. In 1862, Louis Pasteur, realizing that bacteria were the causative agents in the spoiling of milk, demonstrated that if it was heated to 70°C, the bacteria it contained would be killed, and the milk would Figure 16.5: Murchland milking machine, 1889. PART FIVE: TECHNOLOGY AND SOCIETY 794 therefore keep several days longer. Later developments of pasteurization were to improve the fitness of liquid milk for human consumption, since heating was also shown to destroy the bacteria responsible for tuberculosis and brucellosis. Both diseases reduce the efficiency of cattle, but more significantly can also be transmitted to humans by the consumption of milk. By removing a large percentage of its water content, and therefore increasing the relative proportions of fat, milk can be turned into butter, which has slightly better keeping properties. Butter-making was a laborious and time- consuming task, and offered plenty of scope for contamination. The first stage of the process is to separate the fat content of the fresh milk from the heavier water and other solids. To achieve this, milk is traditionally allowed to stand for several hours in shallow bowls so that the cream will form on its surface. The cream is then either skimmed off using special ladles, or else the heavier liquid is drained off from below. It is then placed in a churn and agitated continuously for a considerable period, during which time the fats will coagulate into butter, and the liquid fraction, known as buttermilk, can be drained off. The length of time required to achieve this result will again be dependent on factors such as temperature. Even before the manufacture moved from farmyard to factory, methods were employed to mechanize the arduous work of churning and the horse wheel, already in use in other contexts, was adopted on some larger farms. However it was not until the 1870s that mechanical means were applied to the cream separation process. The early work on these developments occurred in Germany and Scandinavia and were quickly adopted in the major milk producing areas of the world. The principle commonly applied was that of the centrifuge. Milk placed in a fast-spinning chamber will separate in such a way that the heavier solids pass into an outer chamber and are drained off, while the lighter cream will be collected in the inner chamber. Not only is this method much faster, and therefore removes the need to leave standing milk open to contamination for long periods, but it also separates the milk more efficiently, realizing a higher percentage of the cream contained within it. Developed in Scandinavia, hand-powered or belt driven separators had become standard features of larger farm dairies by the late 1880s. The de Laval was exhibited at the Royal Show in England in 1879, and although there were numerous others involved in the development, it is this name that is most closely associated with early cream separators. By a different process it is possible to make soft cheeses, and by applying physical pressure to a particular type of soft cheese, so as to squeeze even more water from it, it is possible to make the hard cheeses which can be stored for appreciable periods. When milk is allowed to stand and the cream content rises to the surface, a slow fermentation will take place which will raise its acidity. If rennet is added to the milk at the correct temperature and acidity, then a solid curd will be AGRICULTURE 795 formed containing the fats, and from which will be expelled a large percentage of water. The liquid fraction, known as the whey, is drained off, and the curd will be cut to allow more water to drain from it. In each of the stages a slightly different approach will alter the physical nature of the curd, and therefore its final texture and flavour as a cheese. In the final stages the curd will be milled into very fine pieces, before being placed in a mould and then pressed under heavy weights for a number of days. This will allow further water to be squeezed out, and will result in a firm or hard cheese, depending on the accumulation of processes up to this point. Finally the cheeses will be left under controlled conditions to mature, during which time they will have to be frequently turned to ensure an even treatment throughout their mass. Each of the stages described is fraught with difficulties. Environmental conditions such as temperature and humidity will affect the fermentation process, and therefore the acidity of the curd. Bacterial action may be intended at certain stages, and for particular cheeses, but the presence of the wrong strains of bacteria, or the introduction of desirable bacteria at the wrong time, can have disastrous consequences on the final results. The milking of animals in the open, the use of wooden receptacles, and the difficulty of keeping animals or equipment clean under such conditions, leave ample opportunity for contamination to occur. The problem was often compounded by the fact that the milk was left uncooled, thus allowing the bacterial population to multiply. In Europe there is little evidence for the provision of buildings specifically set aside for milk processing until the sixteenth century. Up until that time both the processing and the maturing is likely to have been carried out within the domestic or the livestock areas of the holding, with all the associated problems of contamination that this implies. By the early nineteenth century the need to sterilize equipment had been recognized, and although it may still have been common practice to milk cows in the field until the latter half of that century, the new farmsteads being created at this time would invariably be equipped with a separate area for the stalling and milking of cows. By the mid-1800s temperature control was also recognized to be an advantage, and the realization brought about changes in dairy design to create a cool environment in which to process and store the dairy products. In the USA the availability of commercial ice was utilized to the same end, and by 1843 ice was being used to facilitate the transport of this perishable commodity. The idea was quickly extended and by 1851 refrigerated rail cars were being used to transport butter over great distances. Because of the high risks of contamination, and also because of the bulky and awkward nature of the raw material, the processing of milk has to be carried out as quickly, and therefore as close to the lactating animal, as possible. As transport systems have improved, and as the urban market has increased in size, so the processing has moved further and further away from PART FIVE: TECHNOLOGY AND SOCIETY 796 the farmstead. The availability of refrigeration to farm scale operations has allowed the raw material to be cooled to a temperature at which chemical changes are minimized, and this factor, linked to improvements in road and rail transport, has made possible the centralization of processing into factories that can take advantage of economies of scale. Essentially the principles of butter- and cheese-making have not altered, but a better understanding of the processes involved and an ability to control environmental factors between the animal being milked and the shop counter has greatly reduced the risks, and permitted the presentation of a consistent and high quality product. POULTRY FARMING Poultry are another species of great significance in the history of animal domestication, although the most widely distributed representative, the domestic fowl, would appear to have arrived rather late on the scene. Earliest evidence from the Indus valley can be dated to about 2500 BC, although claims are made for an earlier Chinese origin. It had reached the Middle East at least by the first millennium BC, and the Mediterranean by the sixth century. The ancient Egyptians incubated poultry eggs by placing them in dung heaps, where the heat would remain constant whatever the outside temperature, a method recorded by the Roman writer Pliny, but beyond this example it would appear that the rearing of chickens remained a natural process until the nineteenth century. The constant temperature was the essential feature of the dung heap, and until a device could be invented to control heat application, an artificial means of incubating was not feasible. In 1883, Hearson invented a device which made possible the thermostatic control of temperature, and with this it was possible to regulate the temperature in a water jacket surrounding a container for the eggs. While this might have greatly facilitated the incubation process, and in doing so improved the percentage of chickens obtained from a batch of eggs, the poultry industry continued to be based on free range, labour-intensive methods for both egg and meat production. Although developments did occur earlier, it is only since the Second World War that full automation has allowed the economies of scale that have made poultry the cheapest meat available to the consumer. Egg production has been mechanized in the same way, and although the economic benefits are obvious, the poultry industry more than any other represents to a number of people a disquieting attitude by western society to the welfare of farm animals. FOOD PRESERVATION Refrigeration The storage of any food materials raises problems because it is food to much else other than man. Animals, bacteria, fungi, insects and plants can all cause AGRICULTURE 797 losses to stored material. As with much of human discovery, it is likely that methods of storage were discovered by accident and exploited from necessity. Thus it is possible to imagine a hunter in the Arctic regions being forced by unfortunate circumstance to sample the meat from a frozen carcase discovered by chance. It would not be such a major step to freeze meat deliberately in times of abundance to avert a repetition of the incident. Evidence for the intentional freezing of food in prehistoric times has been found in several excavations in the Ukrainian Republic of the USSR. At a site near the town of Mezhirich, in a habitation area dated to about 15,000 years ago, storage pits cut into the permafrost have been excavated. For affluent groups living outside these areas of permafrost, but aware of such storage methods from trading contacts, the idea of moving ice to permit long-term storage may not have been such an absurd idea. In more recent times the distances involved may have been quite considerable. There is certainly literary evidence in classical times of the use of snow and ice to preserve food, and the practice was still to be found in the nineteenth century, when ice houses were a feature of the wealthier estates. Ice was certainly used in areas in which it was comparatively accessible or could be easily transported. As early as the sixteenth century some of the coastal Mediterranean towns could boast of a year-round supply of ice. By the 1660s the first ice houses were being built in Britain and other areas with similar supply problems. In America the potential market for ice was readily exploited for both home and overseas sales. In 1833 a shipment of ice was successfully transferred from Boston to Calcutta, and this was to be the start of a massive trade. One company alone required storage facilities for nearly 20,500 tonnes of ice. Ice-making machines were to appear by the middle of the nineteenth century, but the trade in ice continued well beyond this time. The invention of refrigeration brought the concept into practical application and was to have far reaching effects not only on the diets of the western world, but also on their agricultural economies. In 1875 a small quantity of chilled beef was successfully transported from New York to Britain. Two years later the SS Paraguay sailed from Buenos Aires bound for France with a consignment of frozen meat. The success of this voyage led to a flood of meat from North America, over 32,600 tonnes being transferred in 1880 alone. Australian exports began the same year, though the response to the idea was much more slowly taken up, only 400 carcases of mutton and some 51 tonnes of beef reaching the UK in that year. Initially natural ice refrigeration was used, but in 1879 the first refrigeration machine was fitted into a ship, and by 1891 this had become the normal method used. The labour-extensive range farming possible in these new territories allowed frozen products to be sold in Britain at a price below that achievable by the home producers. This factor, together with the development of steamships, which made possible the swift transfer of grain from the prairies of America to the mills of Europe, was to have a devastating PART FIVE: TECHNOLOGY AND SOCIETY 798 effect on British agriculture in particular. Recovery did not occur until the First World War, when this trade was hindered by submarine blockade. Once frozen, most products can be stored for appreciable periods, but the early freezing procedures were slow, and the volume that could be handled therefore limited. In 1924, Clarence Birdseye developed a method for quick freezing which allowed for greater volumes of produce to be handled speedily. Although he sold his company within a few years, the name was retained and became for a time synonymous with the idea of convenience food. In 1930 frozen peas were first introduced, and in America it was possible to buy precooked frozen foods as early as 1939. Canning Australia and America both raised huge herds of cattle and sheep, and refrigeration was not the only attempted solution to the lack of a home market. In 1809 the Frenchman Nicolas Appert invented a method for the long-term storage of perishable foods, whereby the foods were sterilized by boiling and then sealed into glass jars. An English merchant developed the idea by using metal containers, and in 1811 the first canning factory was established in Britain. The Australians began to export canned meat in 1847, selling mostly to the British Admiralty. The armed forces of various countries seem to have been the major market for these early products, but by 1867 the Australian shipments were available for general sale in Europe, and by 1871, South American producers were also contributing to these supplies. Salting Salting was also an important method of meat preservation, and although its use continues to the present day, in the West it is most usually found as a means of producing a distinctive type of meat, such as bacon or ham, rather than purely as a means of achieving long-term storage. The hieroglyphic sign for salt does not appear in the early scripts of the Middle East, and its use is therefore likely to have developed later. Its importance is reflected in the word ‘salary’ which derives from the Roman word for salt. People do exist whose diet is totally devoid of added salt, but it is unusual, particularly if the food preparation involves any degree of boiling. As a preserving agent it had great economic importance, and was used extensively before it was superseded by refrigeration. Initially the latter increased rather than decreased the volume of meat being salted, since the optimum temperatures for the process precluded summer curing. With the advent of refrigeration machinery it became a year- round occupation. AGRICULTURE 799 Margarine Long-term storage of food has become a major stage in the journey from the farm gate to the table and chemical rather than biological processes have become increasingly important. The production and sale of margarine is an example of this trend. In 1869 the French chemist Mège-Mouriez patented a process which he had devised to utilize the hard suet fat from cattle, by processing it and adding to it other animal wastes to produce a soft butter substitute. It was sometimes blended with butter, but increasingly vegetable oils were used to alter the taste and texture of the product. In 1923 the first margarine made purely from vegetable oils was put on the market by Van den Bergh & Jurgens. Present-day anxieties over animal fats have benefited the sales potential of a product which met with considerable market resistance in its early development. Cereal storage Plant products are also susceptible to damage, and even cereal grain, which gives such an appearance of long-term stability, can be very easily spoilt. It also provides appetizing food to rats, mice and many other lesser pests. In prehistory there is strong evidence for the storage of grain in pits in the ground. These are to be found in widely varying geographical situations, and the distribution of their use indicates that the idea was independently discovered by several totally separate communities. It is essential that the ground is well drained and that there is a low water table. The pits may be lined, though this is not always the case, and once filled they are sealed with a plug of clay. The seeds in contact with the moist walls will germinate, and may begin to rot, but both processes use up oxygen and give off carbon dioxide: this breakdown continues until the carbon dioxide concentration reaches such a level that it kills off the bacteria, and any other pest which might be contained in the pit. The contents of the pit will then remain in extremely good condition until such time as the seal is broken. Recent experiments have shown that corn stored in this way will be of sufficiently good quality for human consumption, and also that a very large percentage of the seed will subsequently germinate, and the method is therefore of value in the storage of seed corn from one year to the next. During the Roman period in Europe, and even earlier in China, purpose designed buildings were being used for the storage of very large quantities of grain. As early as 700 BC grain storage organized by the state was being carried out in China. The motives behind the action were obviously to store in good times the food that would be required in bad; the incentive was as much political as humanitarian, since the idea was to stabilize prices, and therefore to PART FIVE: TECHNOLOGY AND SOCIETY 800 ease public unrest. The effective running of the concept required strong political control, and it is perhaps significant that it was not until about AD 600 that a successful scheme was brought into being, and then run for an extended period. Biblical and other sources attest to the recognized need to store grain against bad times, and the efficient and powerful state system that was required to put such ambitious policies into practice. To work properly, and to ensure that the system was not abused by those charged with its administration, there was the need for rigorous book-keeping, and this in itself may have been the stimulus for several societies to develop their own scripts, and ultimately to establish the written word as a means of communication. The storage of grain above ground leaves it highly exposed to wastage from birds and rodents and was the cause of huge losses in antiquity, as it continues to be today. To an extent building design can limit these losses, but it can do little to diminish comparable losses from insect and fungal attack. Perhaps one of the most urgent problems still to be resolved in Africa is not just the production of food, but also its safe storage. European mediaeval records give a consistently and depressingly low return on yields, suggesting figures for seed harvested which are as low as only three or four times the volume sown, but it is more likely that the amount is in fact the quantity used, and the low figures therefore reflect not only poor yields, but also losses subsequent to harvest. In contrast the Chinese literature of the same period, and even records as early as 200 BC, make claims to a thirty-fold return on grain sown. In part this will reflect the higher yields possible because of very high labour input, but it is probably no coincidence that insecticide treatment, of both seed corn and corn stored for subsequent consumption, is a subject considered by the Chinese chronicler but not the European counterpart. In order for cereals to store well it is essential that the moisture content in the grain should be below 12 per cent of total weight. This was originally achieved by harvesting and drying the grain in stocks in the field, a method which was simple and efficient in the right climate or season, but prone to disaster when conditions were less favourable. Corn drying could be achieved by spreading the grain in the sun, or artificially in specially designed buildings, as was sometimes practised by the Romans. Up to the twentieth century these methods were all that was available to the farmer, and the population as a whole lived with the spectre of lean times which could be inflicted by the vagaries of climate. The arrival of the combine harvester, particularly in the European context, made an artificial means of drying an essential process of harvest. Efficient drying systems, linked to the capabilities of the modern harvester, have allowed the recovery of crops in conditions which would have been the cause of major shortages before the war. This capacity, together with improvements in genetic and chemical technologies of crop growth, has allowed western agriculture to claim the ability to feed itself and provide a reserve for poor years. AGRICULTURE 801 Sugar The use of sugar as a preserving agent has a wide and long history, and can be applied directly as in jams and preserves, or used as a base for fermentation processes which will produce alcohol, itself a useful preservative. Sugar can be derived from a whole range of plants, but in its commercial form was initially obtained from sugar cane. Grown in India as early as 1000 BC, its cultivation was taken westwards by the Arabs. It was introduced into southern Europe in the eighth century AD, and first introduced into the New World in 1493 when Christopher Columbus took cane to the West Indies. This area became the major world producer, being able to compete successfully against others because the labour required for its production was supplied by slaves from West Africa and elsewhere. In the 1740s the German chemist Andreas Marggraf developed a method for the extraction of sugar from sugar beet, and although the effect was far from immediate, the process was eventually to make Europe a major sugar producer, with profound consequences to the Caribbean economy. Alcohol is a product of the fermentation of the natural sugars that are to be found in plant materials. As such it is likely that it was encountered accidentally by prehistoric man who, attracted by its flavour and effect, later developed its use in the production of a range of beverages. Grapes, cereals and many other plants have been utilized to produce alcoholic drinks, the strengths of which would depend on the method of production. Although distillation may have occurred accidentally because of the kind of receptacle used in some other process, it is unlikely that it was knowingly and deliberately carried out until well into the historical period. Whatever the motives for producing alcoholic beverages, the end result was not only palatable, but it stored extremely well and could also be nutritious. William Cobbett, writing in nineteenth-century Britain, condemned the introduction of tea, since it replaced beer in the diet of the labourer, and therefore deprived those who could least afford it of the nutritious benefit of that beverage. Others would have viewed alcohol less charitably, but its production in its many forms has occupied considerable acreages, and been of concern to farmer and brewer for thousands of years. More recent developments have seen the potential of an industry producting fuel alcohol from agriculturally produced raw materials in the attempt to replace expensive or diminishing supplies of oil. It is likely that agriculture will be increasingly seen as a source of industrial raw materials. CONCLUSION The term ‘revolution’ has been applied to three separate transition points in agricultural history. The change from a hunter gatherer economy to one based . distances. Because of the high risks of contamination, and also because of the bulky and awkward nature of the raw material, the processing of milk has to be carried out as quickly, and therefore. farmer, and the population as a whole lived with the spectre of lean times which could be inflicted by the vagaries of climate. The arrival of the combine harvester, particularly in the European context,. wrong strains of bacteria, or the introduction of desirable bacteria at the wrong time, can have disastrous consequences on the final results. The milking of animals in the open, the use of wooden