There cannot be the slightest doubt that it is this motive--the effort to supplement the imperfect opportunities for self-development offered by our restrained, mechanical, and laborious civilization--which plays one of the chief parts in inducing women to adopt, temporarily or permanently, a prostitute's life. We have seen that the economic factor is not, as was once supposed, by any means predominant in this choice. Nor, again, is there any reason to suppose that an over-mastering sexual impulse is a leading factor. But a large number of young women turn instinctively to a life of prostitution because they are moved by an obscure impulse which they can scarcely define to themselves or express, and are often ashamed to confess. It is, therefore, surprising that this motive should find so large a place even in the formal statistics of the factors of prostitution. Merrick, in London, found that 5000, or nearly a third, of the prostitutes he investigated, voluntarily gave up home or situation "for a life of pleasure," and he puts this at the head of the causes of prostitution.[202] In America Sanger found that "inclination" came almost at the head of the causes of prostitution, while Woods Hutchinson found "love of display, luxury and idleness" by far at the head. "Disgusted and wearied with work" is the reason assigned by a large number of Belgian girls when stating to the police their wish to be enrolled as prostitutes. In Italy a similar motive is estimated to play an important part. In Russia "desire for amusement" comes second among the causes of prostitution. There can, I think, be little doubt that, as a thoughtful student of London life has concluded, the problem of prostitution is "at bottom a mad and irresistible craving for excitement, a serious and wilful revolt against the monotony of commonplace ideals, and the uninspired drudgery of everyday life."[203] It is this factor of prostitution, we may reasonably conclude, which is mainly responsible for the fact, pointed out by F. Schiller,[204] that with the development of civilization the supply of prostitutes tends to outgrow the demand.