The most reliable figures I have yet obtained came recently to hand through the courtesy of Dr. Ziegelman, one of the resident psychiatrists at Kings County Hospital, and he tells me that of 454 female admissions to the observation ward there, from October 1, 1914, to March 18, 1915, there are twenty-six cases of puerperal insanity, practically 5¾ per cent. These are not very different, except suggestively lower than Jones, of London, who, in 1903, found from 6.4 per cent, private, and 8.1 per cent poor class patients then in the London Asylum. With so much information, vague and meagre as it is, let us pause a moment and weigh the evidence. As our ideas of pathology change with time, so must our viewpoint as to morbidity and the most recent ideas must settle such questions. Williams, Hirst, Edgar, Webster, De Lee, Jones and Tweedy & Wrench, refer to it absolutely as a disease. Wright of Toronto and the Englishmen Berry Hart and Let are more vague, and only Lewis, of Chicago, calls its occurrence a coincidence. When we consider its frequency, if only we accept the very conservative estimate of Williams and the definite figures from McLeod, of England, of 1–2000 births and are not so radical as Hirst the obstetrician and Clouston the Edinburgh alienist, who state 1–400, to say nothing of Fordyce Barker’s 1–80, we must feel that there is more than a coincidence, and if we consider the large percentage who are confined to asylums suffering from it, I feel we have all the evidence needed. Causes must be studied before we can put pathology on a sound basis, to say nothing of diagnosis and treatment. Here again we find many authorities in disagreement and at times extremely vague. Williams, of the school that, I think we all feel has, through the laboratory, magnified the science of medicine perhaps sometimes to the detriment of its art, says: “Puerperal psychoses may be due to one of three causes: Infection, auto-intoxication, or direct liability of the nervous system. Of these, infection is by far the most important. This fact has long been recognized, but it is only of late that the bacteria concerned have been identified, and then only in a small proportion of cases. In two of the three instances which have come under my observation, the infection was due to the streptococcus, and in the third to the streptococcus and colon bacillus.”