But, besides this first plain perception that our strange relation is coming to an end, we may see how in its own working it developes forces which must end it or us. The method of action of our peculiar cat’s-paw combination of the sexes—the mother-father doing the work of the helpless creature he carries on his back; the parasite mate devouring even when she should most feed—has been this, as repeatedly shown: because of sex-desire the male subjugates the female. Lest he lose her, he feeds her, and, perforce, her young. She, obtaining food through the sex-relation, becomes over-sexed, and acts with constantly increasing stimulus on his sex-activities; and, as these activities are made economic by their relation, she so stimulates industry and all progress. But,—and here is the natural end of an unnatural position, a position that serves its purpose for a time, but holds in itself the seeds of its own destruction,—through the unchecked sex-energy, accumulated under the abnormal pressure of the economic side of the relation, such excess is developed as tends to destroy both individual and race; and such psychic qualities are developed as tend also to our injury and extinction. A relation that inevitably produces abnormal development cannot be permanently maintained. The intensification of sex-energy as a social force results in such limitless exaggeration of sex-instinct as finds expression sexually in the unnatural vices of advanced civilization, and, socially, in the strained economic relation between producer and consumer which breaks society in two. The sexuo-economic relation serves to bring social development to a certain level. After that level is reached, a higher relation must be adopted, or the lifting process comes to an end; and either the race succumbs to the morbid action of its own forces or some fresher race comes in, and begins the course of social evolution anew.