HYGIENE, broadly the science and art of preserving and improving health. Health in this instance is defined as soundness of body, that is, such a condition of all its several parts that they are able to perform their functions without difficulty, and every natural appetite can be satisfied without consequent distress. A typically healthy man is defined as one who hves vigorously, who in every part of his life, wherever it may be, does the largest amount of the best work that he can and, when he dies, leaves healthy offspring. The objects of hygiene are the rendering growth more perfect, decay less rapid, life more vigorous, and death more remote. It is sometimes called preventive medicine, but it includes more than prevention; and is sometimes referred to as sanitary science, or the science of health; but its aim is not merely to know, but to act in view of what is known. It is an ancient art, some of its most important precepts formed a part of the wisdom of the Egyptians at least 1500 a.c., and it is probable that from this source were derived many of the sanitary regulations of the Jews as given in the Levitical code. The Mosaic laws recognize the three great principles of cleanli ness, isolation, and wholesome diet with a thoroughness that leaves little to be desired. Hence, the Jews were almost immune for many centuries from the plagues which swept away their Christian neighbors; this was one reason why they were often suspected of starting or spreading the plagues. Thence also, through Pythagoras and the earlier Greek philosophers who studied in Egypt, came the rules of the Asclepiadm, and a large part of the teachings of Hippocrates on this subject. In Egypt, Assyria, India and among the Jews, hygienic rules were framed by the priests, and were promulgated and enforced as a part of their religious sys tems, the reason given for many of rules, such as for ceremonial ablutions, for the avoid ance of certain foods, for circumcision and other matters connected with sexual hygiene, for the disposal of the dead, and for dealing with certain forms of contagious disease, being simply that they were Divine commands. Under the influence of Greek philosophy these rules were modified and placed upon another basis, the effects of various kinds of diet and exercise were discussed, and finally the famous treatise on airs, waters and places, by Hippocrates, placed the whole subject on a much broader foundation than it had, before occupied. In so i far as public hygiene concerned, the ancient legislators had in view what they considered to be the benefit of the community or nation solely, and enforced their regulations to this end with little or no regard to the rights or welfare of individuals. The Jewish laws provide for
driving out lepers and destroying their houses, but not for the care of the lepers themselves. The maxim of the Roman law, Salus reipublicce supremo lex, was executed in the same spirit. Modern hygiene endeavors to preserve both the community and the individual, recognizing that each has rights which should not be sacrificed for the benefit of the other. As regards per sonal hygiene, the teachings of the Greek and Roman writers, and of those of the Middle Ages, consisted mainly of rules for diet and exercise intended for the benefit of kings, nobles and the wealthier classes. The typical ancient work on personal hygiene is the 'Code of Health' of the school of Salernum, which dates from about the 12th century, and was first printed in 1480. It was several times re printed and for over two centuries was the most popular book in existence. The great epidemics of the Middle Ages, from the plague of Justinian to the Black Death, seem to have had little effect in advancing hygiene; they were supposed to be visitations of Providence against which human means availed not. In the 18th century some elementary ideas of hygiene had become known: the prevention of scurvy by lemon juice and vegetable diet, of fail fever by less crowding and more cleanliness, and of smallpox by inoculation, were among the fore most advances. Our new scientific acquaint ance with ultimate causes for the first time enables us to make hygiene a true science on a basis of exact knowledge. The next step made in the 19th century, was the recognition of the difference between typhus, typhoid and relaps ing fevers, which pointed to different causes and therefore require different methods of pre vention. The establishment of a general sys tem of registration of deaths in England in 1838 was a most important step in its influence as public hygiene. The cholera epidemic of 1832 differed widely in the mortality caused by it in different places, and as this became known, public interest on the subject of the causes and possibilities of • preventing certain diseases increased, until, in 1849 a committee on the health of towns, appointed by the Mous,t of Commons, made a most important report upon water supplies, overcrowding, etc. There:. ter development was rapid and by 1858 a general board of health was appointed for the suppres sion of health nuisances, etc. The scientific foundations of public hygiene were laid by -uch men as Pettenkofer, Pasteur and Koch, and their pupils.