Kings, and generals of armies, and rulers of petty nationalities and clans, were the personages who stood out in bold relief; their plans, intrigues, and movements, and the marshalling of their armies for combat, together with the results which followed in the way of conquering and re-conquering of territories, constituted the great business of life among these nations, and furnished the themes of which historians wrote; while the conditions of life, pertaining to the great body of the common people, as to education, modes of living, occupations, and health, were of almost no account. Education related chiefly to military matters, and was practically confined to the higher classes, while the well-being of the common people was of little concern, except so far as it might prove to be of service in the battles of conquest. The manufactories, commerce, machinery; the law, and politics as now existing, and which play so large a part and exert so great an influence on the lives of the common people of to-day, were then practically unknown. The people were divided, for the most part, into two classes, those who fought the battles, and those who tilled the soil, to obtain the wherewithal to sustain both. These conditions immensely simplified the problem of life, as compared with that of the present time, and, moreover, necessitated an existence out-of-doors for the vast majority of persons. 2. At the present time a much smaller number till the soil and follow out-door occupations, and the improved agricultural machinery now so largely used, and the numerous other avenues of life which have been opened so freely to all, are tending constantly to still further diminish it. Large numbers are congregated in factories and mills, and are engaged in mechanical occupations, counting-houses, mercantile and in-door pursuits. Instead of being in the open air, and breathing it in its freshness and purity, they are, for twenty or more hours of the twenty-four, in the confined and vitiated atmosphere of the factory, store, or counting-house, and, what is not unfrequently worse, that of the illy ventilated sleeping-room. In the one case, the blood is purified and nourished by the influence of a large supply of oxygen which it bears to every portion of the system, and especially the brain, while in the other, it is only partially decarbonated, and bears a taint during its whole round of circulation. The thousands who are, in the present, immersed in the dense atmosphere of cities, large towns, manufacturing establishments, and mines of various kinds, were accustomed, in former times, to live largely out-of-doors, and were engaged in such pursuits as tended to develop and strengthen the whole system.