Mr. Malthus closely examined the statistics of European nations when he wrote in 1805. Before the commencement of this century, he found that the time taken for doubling of the populations of Europe was often as great as some five hundred years. This remark had been anticipated by Adam Smith, who had all the materials, had he sufficiently reflected on them, to have written accurately on the Population Question, since he also was acquainted with the rapid doubling of civilised peoples, when they had been conveyed to new and fertile colonies such as the United States. Here, then, was the conclusion of Malthus, which is perfectly obvious when it is clearly stated. Whenever population, in Europe or elsewhere, fails to double itself as rapidly as it does in new countries, it must be checked in some way or other. Proceeding a little further, he adds that it must either be checked by there being fewer births or a greater number of deaths. Whatever tends to produce a smaller number of births is included by Malthus among the _preventive checks_ to population: whatever leads to a greater number of deaths, among the _positive checks_. His travels through Europe were mainly directed towards the inquiry as to what kind of check was prevalent in each European state. In ancient times, he saw that the positive checks to population had everywhere extensively prevailed. Plagues and famines, with war and infanticide, had been the checks in Greece and Rome, as now in China and Hindostan. In the Europe of his day, all of these positive checks existed, in greatly diminished proportions, indeed, but still they were far from unknown. The extreme prevalence of celibacy, however, struck him in all the civilised states of Europe which he then visited. He noticed that, in many parts of the Continent, where the death-rate was lower than elsewhere, it was the custom for the women to marry very late in life. In one canton of Switzerland, where comfort and longevity were most notable, Malthus found, on enquiry, that it was the custom for the spinsters to delay their bridal day till long after the age of thirty. On the other hand, wherever marriages were early, and the birth-rate was high, he found on investigation that the death-rate was also above the average. From this experience of his, he was led to the conclusion that early marriage, as a rule, was certain to lead to poverty and the positive checks to population; and, therefore, in his practical maxims for improving the condition of the poorer classes, he looked forward solely to the exercise of that celibacy, which he had found so often accompanied by long life and material comforts.