The Etiology and Significance of Necrosis (Infarction) of the Placenta; A Biologic and Histologic Study**The papers presented in this issue of the JOURNAL were lead at the Forty-third Annual Meeting of the American Association of Obstetricians, Gynecologists and Abdominal Surgeons, which was held at Niagara Falls, Canada, on September 15, 16, and 17, 1930. Abstracts of the discussions on these papers will be published in the March issue of the JOURNAL.