720 BOOK REVIEWS

There is much of interest to ophthalmolo­gists in this new edition. The work is skill­fully done and carefully edited. The illus­trations are adequate and the printing excel­lent. It is highly recommended.

Derrick Vail.

STATIC AND DYNAMIC ELECTRON OPTICS. An account of focusing in lens, deflector and accelerator. Cambridge Monographs on Mechanics and Applied Mathematics. P. A. Sturrock. London, Cambridge Uni­versity Press, 1955. 240 pages. Price: $5.50. The ophthalmologist is familiar with elec­

tron optics almost wholly from the outstand­ing feats performed by the electron micro­scope in exploring and bringing to light minute structures which are beyond the reso­lution limits of the ordinary microscope. His interests have been in the results or possible applications, and not in the underlying theory of electron optics. Therefore, this book will hold no interest for ophthalmologists gen­erally, although physicists associated with medical researchers will recognize it as a worthwhile contribution to the literature of electron optics.

Dr. Sturrock's treatment of the subject is purely from a theoretic standpoint, in which he presupposes the reader to be fully ac­quainted with matrix and vector mathemati­cal techniques. It is a book for specialists who have long since lost the need (and pos-sibily the capability) to think of electron optics in terms of parallels with "light" optics. The latter field is several centuries old and was cleverly developed on the basis of mechanistic models which enabled the nonspecialist to gain a practical understand­ing of applied optics without formal mathe­matical training beyond trigonometry. Elec­tron optics is a new field, having begun in

1926 when the German physicist, H. Busch, showed that electron beams could be focused by magnetic and electric fields the same as lenses can focus a light beam. As a result, our knowledge of electron optics has de­veloped from the efforts of theoretical physi­cists who could not care less if their compu­tations made little sense to practitioners. Thus, there is hardly any hope that the oph­thalmologist can ever gain a useful mental picture of electron optics in the same sense that he enjoys a familiarity with lens optics which he can visualize as models that func­tion according to simple rules in spite of their rigorous and complicated mathematical formalities when treated according to Max-wellian and Hamiltonian electromagnetic wave concepts.

Lloyd E. Varden, Associate Professor in Engineering,

Columbia University, New York.

L E SYSTEME NERVEUX PÉRIPHÉRIQUE. By Guy Lazorthes, M.D. Paris, Masson et Cie, 1955. 348 pages, 214 figures, index. Price : Clothbound, 4200 fr. ; paperbound, 3500 fr. The author, a professor of anatomy at

Toulouse and a practicing neurosurgeon, in­tegrates in this book—his third on the nerv­ous system—the comprehensive details of the anatomy and physiology of the cranial and spinal nerves in relation to clinical dis­orders, methods of examination and surgical treatment. The text is complete but compact and illustrated profusely by figures that are models of simplicity and interpretation. Of special interest to the ophthalmologist are the several chapters devoted to the optic, ocular motor, trigeminal, and facial nerves.

James E. Lebensohn.