Hygiene, The study of the means of preventing disease and prolonging life is one which dates from very early times. The extent to which inquiry had been pushed at a very early period in this matter is seen on a study of the Book of Leviticus, and, with regard to the Greeks, evidence of a like kind is to hand in the writings of Hippocrates. During the Middle Ages but scant attention was paid to the subject of preventive medicine, and the formidable epidemics which raged in Europe until as late as the seventeenth century, were no doubt attributable in the main to the neglect of this study. Attention came at length to be directed to the evils attendant upon overcrowding, want of cleanliness, and the like, and the great discovery of vaccination at the end of last century opened up the prospect of further development in disease prevention. In the present century considerable progress has been made. The Vaccination Acts have been the means of affording to large masses of the population protection from a most formidable disease; the Factory Acts have done much to ameliorate the condition of workers; and the various Public Health Acts have caused the undertaking of schemes for the supply of pure water, for the disposal of excreta, and have resulted in the abatement of many nuisances. With the growth of the system of registration of deaths, light has been thrown upon the distribution of disease, and the later development of the practice of notifying infectious disease will, no doubt, be productive of increased knowledge and improved means of combating the progress of epidemics. The recognition of the evil effects of breathing a confined and vitiated atmosphere, the demonstration of the relationship of such disease as consumption to dampness of soil, the spread of cholera and typhoid by contaminated water supplies, the connection between food and epidemics (as, for instance, in scarlatina and diphtheria epidemics traceable to milk supplies), and the relation between the diseases of animals and of man - on these and on other matters the study of hygiene has, during the last fifty years, thrown much light. The study has already resulted in a material reduction in the death-rate.