Apparently it was the sinister character of the early factory system, and the ominous unrest which pervaded Europe after the French Revolution, which rather suddenly changed into pessimism this bland optimism about an ever growing population. Malthus published the first edition of his _Essay on Population_ in 1798. This book is undoubtedly one of the great landmarks of human culture, for it focussed the attention of Europe on the necessity of regulating the growth of population. Malthus himself, it seems, hoped that this regulation could be achieved by the postponement of marriage and by continence. It is not clear whether he disapproved of what is now called neo-Malthusianism, or whether he did not regard it as practicable. Nevertheless, within less than twenty-five years James Mill in the _Encyclopædia Britannica_ had in guarded fashion put forward the neo-Malthusian principle, and shortly thereafter, that is in 1823, an active public propaganda was set on foot, most probably by Francis Place, by means of what were known as the “diabolical handbills.” These leaflets were addressed to the working classes and contained descriptions of methods for preventing conception. Some of them were sent to a good lady named Mrs. Fildes, who [p290] indignantly, but mistakenly from her point of view, assisted the nefarious propaganda by exposing it in the public prints. Fifty years later Mr. Bradlaugh and Mrs. Besant had themselves indicted and tried for selling an illustrated edition of Knowlton’s _Fruits of Philosophy_. After that advertisement, neo-Malthusian principles and practices were known and were, therefore, available to all but the poorest and most illiterate. No propaganda so threatening to the established moral order ever encountered such an ineffective opposition. I do not know how much money has been spent on the propaganda nor how many martyrs have had to coerce reluctant judges to try them. But it is evident that once it was known that fairly dependable methods of contraception exist, the people took the matter into their own hands. For the public reasons by which neo-Malthusianism was justified were also private reasons. The social philosopher said that population must be adjusted to the means of subsistence. Man and wife said that they must have only as many children as they could afford to rear. The eugenist said that certain stocks ought not to multiply. Individual women decided that too many children, or even any children, were bad for their health. But these were not the only reasons which explain the demand for neo-Malthusian knowledge. There was also the very plain demand due to a desire to enjoy sexual intercourse without social consequences.