In an edition of forty-one years ago of Fordyce Barker’s “Puerperal Diseases,” he gives the ratio of cases of puerperal mania to total labors in Bellevue as 1–80. I have purposely referred to the age of this book because I shall refer to it again in discussing an attributed etiological factor. Not long ago after this work appeared, McLeod took the statistics of births in England and Wales for four years (1878–82) and found the proportion of women committed for puerperal insanity was 1,794–3,500,000 labors, or 1–2000. Baker himself was interested in the variation of statistics and explains part of the difference from the fact that there were many unmarried women at Bellevue; and while there were also among the foreign records, in the old countries, the fact of being a mother and not a wife was felt far less keenly, if at all than in America! (Pp. 160–191.) Williams refers to more modern statistics of Berkley and of Jones, who noted it in 1 in 616 and in 1,100 labors respectively, but Williams’s own experience has been less frequent. Hirst states “About one in 400 women confined become insane;” a flat if not grammatical statement, and this proportion agrees with, if not taken from, the experience of Clouston of the Edinburgh asylum. Hanson’s figures are about the same, 1–386. Let us get at this subject of frequency from the opposite point of view. Among cases of insanity how many are associated with childbearing? Clouston, of Edinburgh, among 1,500 women, found 10 per cent were classified as suffering with puerperal psychoses and most of the earlier figures (and here we have the first real thought) before the antiseptic era give similar percentages—the New York State hospitals from 1888 to 1895 give only 5 per cent as puerperal in origin. Before we draw a too hasty conclusion, let me quote Lane based on observations in the Boston Insane Hospital for ten years, “that insanity associated with childbirth occurs only one-half as frequently as does insanity among women in general of childbearing age. The vast majority of women who become insane are between the ages of twenty and fifty. The task of bearing and nursing children occupies a considerable portion of the time of the average woman during these ages. Therefore, we should expect a large proportion of cases of insanity to begin during such time even without casual connection.” According to Lane’s view the childbearing process gives a certain degree of immunity to insanity instead of predisposition thereto! On the other hand he points out that there are many more single than married women in asylums—perhaps unmarried on account of their defects. Hirst says of all cases of insanity in women about 8 per cent have their origin in the childbearing process, while Berry Hart gives the lower percentage of five. De Lee, in his textbook—the most recent at my command—gives the high percentage of 10–18 of female inmates affected at this time.