(_b_) It is interesting to note the steady rise in husbands’ petitions during the years 1915-1919—all years of war: the figure 4,076 as against 1,009 in 1919 constituting the most convincing evidence we have of the difficulty with which women tolerate the lack of children or the cessation of child-birth, even when it is due to the absence of their husbands on what was believed to be a “Crusade.” It seems probable that the bulk of these women must have been young, for the total number of divorces for that year, in cases where there was only one child or none, amounts to 3,965. Of course, from my point of view, the value of these figures is lessened by the fact that it is impossible to differentiate between marriages of positive and negative couples; but perhaps the steadiness with which certain characteristic proportions are revealed in them compensates to some extent for this defect. When we add to this Lord Salvesen’s evidence before the Royal Commission on Divorce (1912), in which he declared that in Scotland the proportion of divorces among childless couples was “immensely larger” than that among fertile couples, it can leave little doubt in our minds that, in order to be so constant and universal, this rule must be based on unalterable laws taking their root in deep physiological and psychological conditions, and that the sentimental and emotional factors can be but surface phenomena accompanying rather than affecting the operation of these laws. For, if we have been right in arguing that the presence of children does not operate as a strengthener of the union by cementing the _love_ of married couples, but by meeting certain instinctive needs in their physical and mental constitution, it is clear that the sentimental elements in the union are the most insignificant—hence their inability to tide large numbers of positive couples over the periods of physiological and psychical stress which childlessness or the limitation of the family imposes. (_c_) When we turn to Chart II and examine the figures given for the duration of the marriage up to the time when the petition was filed (for the years 1910-1919), we also note a fact that does not surprise us, and that is the immeasurably higher figures given for the four years lying between the fifth and the tenth years of marriage, than for all other periods. It is precisely during these four years that those two disturbing forces which do most to mar modern marriages are most likely to begin to operate, viz:— (_a_) The irascibility of the wife as the result of the cessation of child-birth; this irascibility showing itself in a decreasing satisfaction with her home and her husband, and an increasing interest in outside amusements and occupations, and in other men. (_b_) The loss of desire for his wife, in the husband, which causes him to seek other sexual experiences.