Historical and Popular Exhibits at the International Hygienic Exposition in Dresden TWO of the most interesting departments of :h.-International Hygienic Exposition which is being held in Dresden are the historical and popular sections. In the historical section the history of hygiene is illustrated by numerous models and pictures, as well as by other means, and similar methods are employed in the popular section, the purpose of which is to give the average visitor a clear and non-technical presentation of the progress of hygiene and to impart some practical information concerning the laws of health. Illustrations and descriptions of some of these exhibits are here reproduced from a recent issue of the Illustrite Zeitung, which is filled with interesting matter relating to the exposition, to which it is entirely devoted. In the historical section the visitor is enabled to review the progress of hygiene from the infancy of civilization to the present day. The record is very incomplete, and is made up of fragments laboriously unearthed by the archaeologist, for the writers of history and the makers of monuments deal almost exclusively with wars and kings, and devote little attention to the life of the people. We know from excavations that the Celts and Germans, before they came into contact with Roman civilization, lived in caves and cellars, and the human bones found in these underground dwellings show that gout and rheumatism were very common, as might be expected. The inhabitants of the upper Nile region were also grievously afflicted by gout. These northern tribes, after the primitive age of furs and skins, wore close-fitting breeches and sleeved shirts of thick wool, in striking contrast to the light and flowing garments of the Romans and Greeks (Fig. 1), and in entire accordance with the difference in climate. The disposal of the dead is a subject of great hygienic importance, and is well illustrated in the historical section. Although cremation, embalming and the sealing of corpses in tight oaken coffins, stone sarcophagi (Fig. 2) and vaults, were probably not adopted for hygienic reasons, they produced hygienic results, especially in view of the widely prevalent custom of keeping the remains of deceased members of the family very near or even in the house. Among other customs of hygienic value but non-hygienic origin may be mentioned bathing, which in many lands was regarded as a religious, rather than a hygienic duty. Again, the ritual requirement of perfect health in animals which were offered in sacrifice (and which, by the way, often constituted the only animal food used) was firmly established among the Babylonians, Egyptians, Jews and Greeks, ages before there was any official inspection of slaughter houses. Hygienic motives, however, were consciously followed by the Greeks, Romans and other ancient peoples in house building, paving, draining, sewerage, water supply, the construction of private and public baths, and in many other things. An ancient Babylonian drain is illustrated in Fig. 3, while Fig. 4 shows a model of the outlet sluices of the Alban Lake. Two institutions of great hygienic value originated in Mesopotamia and were brought to Europe by the Jews— the weekly day of rest and the isolation of diseased persons. In the Middle Ages the precepts of Leviticus were developed into a system of sanitary regulations which, in a desperate warfare waged for centuries, .finally defeated the dreaded Asiatic” invader, leprosy. Fig. 5 shows a rattle used by the leper to give warning of his presence. The epidemics of the plague, and especially the black death (1348-1350) led to the establishment of municipal and state quarantine and other preventive measures which are still employed. The Romans had small military hospitals, but general hospitals, lep-roseries and pest-houses (Fig. 6) originated in the Middle Ages. The characteristic German fondness for bathing was freely indulged even in the Dark Ages, when every village had its Turkish bath. The fashion prevailed, not without abuses (Fig. 7) throughout the Middle Ages, but waned in the seventeenth century in the general depression caused by the Thirty Years' War. In the eighteenth century the “ return to nature” which followed the French Revolution led to a resumption of the practice of bathing in streams, which had previously been prohibited as unseemly. At that time hygiene was earnestly studied in France, the war against the corset was inaugurated, and, in 1802, it general council of health was founded. During the same period Jenner, in England, introduced vaccination, which in a few decades put an end to the frightful epidemics of smallpox which had long ravaged Europe. The epidemic of cholera in England in 1831 contributed greatly to the promotion of cleanliness and of hygiene in general. These are a few of the subjects that are copiously illustrated by the historical exhibits of the exposition, which also show the hygienic progress that has gradually been made in house building, cooking, heating, lighting and clothing, in the installation of prisons, barracks and abattoirs, in travel by sea and land, etc, Fig. 8 shows a model of a chimney such as was used in underground dwellings after the need of such a device had at last become apparent, and Fig. 9 exhibits a diversified assortment of medieval and modern footgear. Few people appreciate the great boon of health until it is lost or seriously impaired. This fatalistic indifference is explained by the general ignorance of hygienic laws. Great advances have been made in physiology in the last few decades, and the cause and the means of prevention, if not of cure, of nearly every disease are known by physicians, but very little of this knowledge has reached the mass of the people. The popular section of the Hygienic Exposition is designed to impart this knowledge, in such a form that it c< ln be understood at a glance. The attentive and intelligent visitor will leave this section impressed with the wonderful complexity of the body and the value of good health, and filled with the resolve to preserve this precious gift with jealous care. The little detailed description of this section that can be given in this article ' will best be presented in connection with the few illustrations here reproduced. Figs. 10, 11, 12 and 13 relate to water and its impurities. Fig. 10 shows an open well lined with a wall of stone and situated near a farmhouse and stable. Not far off is the village pond, on the shore of which stands a small slaughterhouse. The water of the pond, filled with impurities derived from the slaughterhouse, the washing of clothes and many other sources, seeps through the soil to the “ ground water” which supplies the well. Other water carrying impurities from the stable and dung heap, drains, etc., enters the well through fissures in the wall, and dust and other things fall into the open mouth, so that the well water is necessarily impure, and may contain germs of typhoid and other diseases. The conditions shown in Fig. 11 are little better. The well is covered and provided with a pump, and is apparently protected from surface impurities by the impervious stratum of yellow loam which it traverses in its descent. But the wall and the wooden cover of the well in time develop fissures which admit impure water from the ditch at the left and from other sources. Moreover, a cesspool (shown at the right) of later and very faulty construction, also penetrates below the stratum of loam, and directly contaminates the ground water. Such wells often cause epidemics which are carried through a whole village in various ways; for example, a careless baker who allows a washerwoman to test the freshness of his bread by squeezing the loaves with her wet hands. The pump well shown in Fig. 12 is apparently well protected by layers of cement and clay, and the cesspool is made tight by the same means, but the ground water is contaminated by neighboring sources of impurity. Fig. 13 shows a deep pipe well, driven through one stratum of yellow loam and two of blue day. The water is thoroughly protected from contamination from the surface above and near it, and is probably pure. Various types of dwellings are illustrated in Figs. 14 and 15. .Beginning at the left of Fig. 14, the first drawing shows an ancient Hebrew house, which consists essentially of a high wall inclosing an open night shelter. The second dwelling is the primitive hut of the Indians of the Amazon, consisting merely of a roof placed on the bare ground, without walls. The third picture shows a model of a farmhouse in Saxony, with the roof turned up to show the interior. The sleeping- and living-rooms, kitchen (usually chimney-less), barns and stables are all under one roof and within one wall, in defiance of the most elementary hygienic requirements. The fourth dwelling is a Canadian Indian wigwam. The tent is one of the most primitive of human dwellings, and is found chiefly among hunting and nomadic tribes. The open top of this Indian tent is provided with flaps to control the outflow of smoke. Behind the tent is shown a fence which serves as a wind shield, and to right and left are stacked the sledge poles on which the tent and other possessions are carried on journeys. The fifth and last dwelling shown in Fig. 14 is an African Herero hut, consisting of an inverted plaited basket, like an old-fashioned beehive, plastered with clay and cow dung. The first (left hand) drawing in Fig. 15 represents a vertical section of a Point Barrow Eskimo hut, built of logs and covered with snow as a protection against cold. The hut is entered by creeping through a low doorway. The second picture) shows an Italian peasant' s house. The interior is dark and uncomfortable, the windows are not glazed, the roof is fiat, and is a favorite evening resort. The third picture shows an ancient German hut, built of tree t runks wattled with brush. Huts of this type are still used by primitive tribes in various parts of the world. The fourth picture shows a prehistoric German earth-dwelling, consisting of a pit surmounted by a dome of brush covered with clay or moss. The fifth and last picture shows a farmhouse in the German Schwarz-wald, in which house, barn and stables are combined, as in the Saxon farmhouse. Fig. 16 shows a modern hygienic bed and Fig. 17 the old-fashioned alcove bed, wMch was apparently devised to prevent access of fresh air to the sleeper. Fig. 18 illustrates the comparative tensile strength of human bone and of oak. A rod of bone having a cross-section of one square millimeter will sustain a weight of 15 kilogrammes, while a similar oak rod will sustain only 10 kilogrammes. By pressing the lever and raising the weight shown in Fig. 19, which represents the effort made by the heart in each pulsation, the visitor can obtain a practical idea of the great force of the heart' s beat. The effect of clothing in diminishing radiation of heat from the body is illustrated by Fig. 20. When the temperature of the air is 50 deg. F., the temperatures of the bare hand, the skin of the arm clad in a knit shirt and a woolen coat, and the other surfaces of the shirt sleeve and coat sleeve, are respectively 84.2, 89.6, 78.8 and 69.8 deg. F. Hence the difference in temperature between the coat sleeve and the air is only 19.8 degrees, while the difference between the bare hand and the air is 34.8 degrees, and the radiation from the clothed arm is correspondingly less than that from the bare hand. The heating and cooling effects of hats and caps are illustrated in Fig. 21. In the sun, with an external temperature of 96.8 deg. F., the temperatures inside the hats are as follows: No. 1, yacht club cap, 98.6; No. 2, Prussian helmet, 97.7; No. 3, English cap, 94.1; No. 4, black derby hat, 92.3; No. 5, high silk hat, 89.6; No. 6, soft white felt hat, 86; No. 7, light straw hat, 79.9; No. 8, Panama hat, 77.9 deg. F. The First International Congress of Aerial Law ON May 31st and June 1st and 2nd, the First International Congress of Aerial Law met in Paris under the auspices of the Co-mite International Juridique de VAviation. The efforts of the committee are directed especially to the establishment of practical regulations for aerial traffic as such regulations shall become necessary. The other objects of the committee are the collection and preservation, in a central place, of all interesting cases and documents relating to aerial law, the discussion and preparation of laws passed by parliaments and local authorities, and the imparting of information and advice to societies and individuals who may present questions concerning the legal aspects of aerial traffic. In some cases the committee may assume the role of arbitrator in disputes. The committee has undertaken the preparation of an aerial code consisting of five sections (general public rights, private rights, police ordinances, custom house regulations and penal laws). In a recent issue of the Deutsche Zeitschrift fwr Luftschiffahrt the work of the International Committee is thus described by the head of the German delegation, Dr. Alex Meyer: The separate chapters ' of the code tentatively adopted by the international committee are submitted to each national delegation and the result of the deliberations of each national delegation is communicated to the international delegate in Paris. The diverse views thus collected from all the countries are discussed at the monthly sessions of the international committee, and form the basis of a provisional chapter, the definite form of which is established at the annual international congress. The first congress, just held, determined the method of voting, and drew up the first five chapters of the code, relating to general public rights. It was decided that each country represented should have one vote. The five chapters as adopted read substantially as follows: chapter i. general rules of aerial traffic. Article 1. Aerial traffic is free, with the reservation of the right of each State to make certain regulations for the space above its own territory, for the preservation of its own safety and the lives and property of its inhabitants. chapter ii. nationality and registration Of afjrial VESSELS. Art. 2. Every aerial vessel must have a single nationality. Art. 3. The nationality of a vessel is determined by that of its owner. When the owner is a company, the nationality of the vessel is that of the place where the company has its seat. If a vessel belongs to several owners of different nationalities, its nationality is that of the owner who possesses a two-thirds interest in the vessel. Art. 4. Every vessel must bear an easily recognizable mark of nationality. Art. 5. Every vessel must carry papers of identification containing all aecessary information. Art. 6. No owner of an aerial vessel may extend his flight beyond the limits of an aeronautic park unless the vessel has been registered in a list kept by the proper authorities. Each State shall make rules for registration in its own territory. Art. 7. Every vessel must carry a mark indicating its place of registry. Art. 8. The registration list shall be published. chapter iii. landing. Art. 9. Landing in open fields is permitted. Art. 10. It is forbidden to land in fortified places or within a radius established by the military authorities,- or within towns and cities except in open spaces designated by the authorities. Art. 11, The owner of the vessel shall be liable for all damage caused by landing, except in so far as such damage is caused by the fault of the party injured. chapter iv. JEttiSOn. Art. 12. Jettison includes all voluntary dropping of objects from the vessel. Art. 13. Except in cases of imminent peril it is forbidden to drop any object which can injure persons or property in any manner. Art. 14. In case of injury so caused, the owner of the vessel shall be held liable. chapter v. wrecked and abandoned vessels. Art. 15. Every person who finds a damaged or abandoned aerial vessel, or any part thereof, must notify the proper authorities. Art. 16. The authorities so notified shall immediately take proper measures to preserve the wreck and restore it to its owner. Art. 17. The owner may claim his property at any time within one year from the day of discovery and after he has paid the cost of salvage and preservation. The owner is also required to ,pay to the finder a reward equal to 10 per cent of the value of the recovered vessel, after all costs have been paid.