Effects of epidemics on registers to have occurred frequently, and in almost all the instances in which they were such as for the deaths to exceed the births, they were immediately succeeded by a more than usual proportion of marriages, and in a few years by an increased proportion of births. The greatest number of marriages in the whole table occurs in the year 1751, after an epidemic in the year 1750, in which the deaths had exceeded the births above one third, and the four or five following years contain the largest proportion of births. The extremes of the proportions of births to marriages are 42 to 10, and 34 to 10, the mean of the 68 years 38 to 10. The remaining tables contain similar results, but these will be sufficient to show the variations which are continually occurring in the proportions of the births and marriages as well as of the deaths, to the whole population. It will be observed that the least variable of the proportions is that which the births and marriages bear to each other, and the obvious reason is, that this proportion nearly expresses the prolificness of marriages, which will not of course be subject to great changes. We can hardly indeed suppose that the prolificness of marriages should vary so much as the extremes which have been mentioned. of births, deaths, and marriages. Nor is it necessary that it should, as another cause will contribute to produce the same effect. The births which are contemporary with the marriages of any particular year belong principally to marriages which had taken place some years before, and therefore if for four or five years a large proportion of marriages were to take place, and then accidentally for one or two years a small proportion, the effect would be a large proportion of births to marriages in the registers during these one or two years; and on the contrary, if for four or five years few marriages comparatively were to take place, and then for one or two years a great number, the effect would be a small proportion of births to marriages in the registers. This was strikingly illustrated in the table for Prussia and Lithuania, and would be confirmed by an inspection of all the other tables collected by Sussmilch, in which it appears that the extreme proportions of births to marriages are generally more affected by the number of marriages than the number of births, and consequently arise more from the variations in the disposition or encouragement to matrimony, than from the variations in the prolificness of marriages. The common epidemical years that are inter Effects of epidemics on registers spersed throughout these tables will not of course have the same effects on the marriages and births, as the great plague in the table for Prussia; but in proportion to their magnitude, their operation will in general be found to be similar. From the registers of many other countries, and particularly of towns, it appears that the visitations of the plague were frequent at the latter end of the 17th and the beginning of the 18th centuries. In contemplating the plagues and sickly seasons which occur in these tables, after a period of rapid increase, it is impossible not to be impressed with the idea that the number of inhabitants had, in these instances, exceeded the food and the accommodations necessary to preserve them in health. The mass of the people would, upon this supposition, be obliged to live worse, and a greater number of them would be crowded together in one house; and these natural causes would evidently contribute to produce sickness, even though the country, absolutely considered, might not be crowded and populous. In a country, even thinly inhabited, if an increase of population take place before more food is raised, and more houses are built, the inhabitants must be distressed for room and subsistence. If in the Highlands of Scotland, of births, deaths, and marriages. for the next ten or twelve years, the marriages were to be either more frequent or more prolific, and no emigration were to take place, instead of five to a cottage, there might be seven, and this, added to the necessity of worse living, would evidently have a most unfavorable effect on the health of the common people. CHAPTER XI. General deductions from the preceding view of Society. THAT the checks which have been mentioned are the immediate causes of the slow increase of population, and that these checks result principally from an insufficiency of subsistence, will be evident from the comparatively rapid increase, which has invariably taken place whenever, by some sudden enlargement in the means of subsistence, these checks have been in any considerable degree removed. It has been universally remarked that all new colonies settled in healthy countries, where room and food were abundant, have constantly made a rapid progress in population. Many of the colonies from ancient Greece, in the course of one or two centuries, appear to have rivalled, and even surpassed, their mother cities. Syracuse and Agrigentum in Sicily; Tarentum and Locri in Italy; Ephesus and Miletus in Lesser Asia; were, by all accounts, at least equal to any of the cities of |