An Experimental Investigation into the Etiology of Accidental Hæmorrhage and Placental Infarction *Read 10th March 1926.

In spite of much research work within recent years comparatively little has been discovered concerning the causation of accidental haemorrhage. Most writers, including Gordon Ley1 and Whitridge Williams,2 have agreed in ascribing it to toxaemia of pregnancy, while others, led by James Young of Edinburgh, have looked upon the toxaemia as secondary to, and consequent upon the haemorrhage. According to Young,3 the placenta separated by haemorrhage undergoes necrosis, and during the early stages of the necrosis autolytic products are absorbed into the circulation through the portion of placenta still attached to the uterine wall. These products, acting upon the maternal