The Retina

Dr. Polyak has brought together in over 600 pages an admirable account of researches dealing with the structure of the retina in man, ape, and monkey and has analyzed the mechanisms upon which the various visual functions may depend. The book is, therefore, of particular interest to students of anatomy, ophthalmology, neurology, physiology, and psychology. There are 34 chapters, the first of which gives a general outline of the vertebrate visual system. The text which follows is divided into five parts. In Part I an excellent summary is given in five chapters dealing with various valuable technics for gross and microscopic studies of different parts of the visual system. Preparations for observations on both fresh and fixed material are considered and brief descriptions are given of experimental methods applied to the eyeball , optic nerve, and the intracranial portions of the optic pathways. Parts II and III consist of seven chapters devoted to a historical account from the early Greek periods to modern times. Speculations on the functions of parts of the eye and on the conveyance of visual impulses to the brain are presented in this interesting story. Two of the chapters are devoted to Arabic contributions and are illustrated by newly discovered diagrams from ancient manuscripts. There are many references for those who wish to follow the eye through the pages of medical history. In two other chapters the historical picture of ideas concerning the retina is presented with emphasis on the advancement of knowledge gained through the development of histological technics. Another chapter is devoted to a critical evaluation of modern concepts of photoreceptor mechanisms and it presents a challenge to the anatomist to give a more penetrating picture of the relation of retinal elements. Part IV is a large section of sixteen chapters dealing with the stratification of the retina. Detailed studies of the individual elements and a consideration of regional differentiation, with occasional references to the lower animals, give an extensive survey welcome to ophthalmologists. Considerable space is devoted to the ganglionic components and the nature of the physiological role of cellular components is treated at length. In the five chapters of Part V the minute organization of the visual system is analyzed for evidence to explain the differentiation of nervous currents. In this last section the author gives a critical discussion of ideas on spacial, light, and color perception. Guided by the recognition that …