Excerpt from The Muscles of the Eye, Vol. 1 of 2: Anatomy and Physiology Including Instruments for Testing and Methods of Measurement The importance of this subject becomes apparent when it is remembered that abnormal conditions of the ocular muscles - including those involved in accommodation - constitute, for most ophthalmologists, by far the largest group of cases presented for treatments. Opticians also have to deal constantly with questions in which the ciliary muscle is a factor, and even if they limit their work to giving glasses for presbyopia and hypermetropia, it is desirable that it be done intelligently. All physicians are confronted at times by the numerous reflexes associated with faulty action of the ocular muscles, while their partial or total paralyses are important guides for the neurologists in diagnosis and treatment. And yet the widely differing views concerning many fundamental facts and principles indicate that thus far we have succeeded only in accumulating a considerable amount of ignorance in regard to this subject. Indeed, there is hardly any branch of medicine about which so much has been written, and of which we know in proportion so little. It would, therefore, be worse than useless to add to this mass of literature were it not on a plan different in its scope from that of any of the detached articles or text-book chapters on the subject. The objects of this study are: First. To collect data relating to this subject, separating as clearly as possible demonstrated facts from statements based on theory. Second. To formulate these facts concisely, and in the simplest terms possible. In doing so it is necessary to retain a few mathematical statements, either because they can not be found elsewhere, or to show the basis of other facts. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.