Ovulation in the Human Ovary *Read 14th March 1928.

lower animals, but in the case of human beings the evidence of its occurrence rests solely upon the demonstration of the presence of follicles immediately prior to rupture and of follicles which have recently ruptured. Although it is easy to demonstrate ripening follicles in the human ovary, it is only rarely that specimens of recently ruptured follicles can be found and for this reason it is not until recently that the mechanism of ovulation has been accurately described. The first of the changes leading to ovulation is the process of ripening of the Graafian follicle. The primordial follicle consists of an ovum surrounded by a single layer of flattened cells and these latter cells subsequently become differentiated to form the granulosa cells of the follicle. During ripening two further layers of cells appear, an inner termed the theca