The physiology of the vascular circulation in the human eye is of fundamental importance to the whole of ophthalmology, and, because the behavior of the normal and abnormal phenomena are observable within limits, certain analogies, rightly or wrongly, have been drawn with regard to vascular physiology and its alterations elsewhere in the body. Ophthalmodynamometry, a subject of peculiar interest to many workers in this field, appears to deserve review sequential to 1926, when Duke-Elder1so aptly observed : The unwieldy literature that has accumulated upon the subject is swollen with wearisomely protracted and often acrimonious discussions of unnecessary hypotheses, with defective and confused experiments based on unsound physiological reasoning, with a multitude of theorizings and a paucity of facts. REVIEW OF LITERATURE Vascular Pulsations. —The basic modifying factor of intraocular pressure has been responsible during approximately two generations for the continuing controversy with regard to the essential principles involved, ever