The name of Ragnar Granit is authority enough to make this volume of the utmost importance to those interested in the physiology of the retina and brain. Stimulated by the work of Sir Charles Sherrington and Ramon y Cajal, the author followed the work of these masters together with that of Adrian at the Eldridge R. Johnson Foundation of Pennsylvania University; at Helsingfors, and at Oxford. In spite of financial assistance by the Rockefeller Foundation, a laboratory worker has advanced slowly and methodically and even has been able to introduce practical, clinical methods.
Beginning with the peripheral nerve, Granit advanced his studies with electrical potentialities of the retina and optic nerve to the end that even minutiae such as rods, cones and ganglion cells are indeed recorded, in lower animals, as to their electric phases in the conduction of nerve impulses. The duplex nature of the retinal discharges in the