Page:Popular Science Monthly Volume 19.djvu/284

272

has for many years made the eye a subject of special study, from the point of view assumed in this book. And this is the way this wonderful organ will in future have to be studied. Its interest as an object of investigation is inexhaustible. Its mechanism and action are roughly explained in every physiology; but, to state all that is known about it, in its several aspects in health and disease, would require whole libraries, Helmholtz has made a large and a profound book on physiological optics, devoted to an elucidation of the relations of light to the visual organism, while the psychological relations of the organ of vision have yet to be explored. The eye is, therefore, a subject so complex, obscure, and extensive, that it must in future be approached on different sides by separate investigators. In taking up the eye with a view of explaining the mechanism and process of sight as single and double, our author declares that he does not know the existence of "any work covering the same ground in the English language." He, therefore, claims that it meets a real want, and fills a real gap in scientific literature.

In regard to its form. Dr. Le Conte says: "I have tried to make a book that will be intelligible and interesting to the thoughtful general reader, and at the same time profitable to even the most advanced specialist in this department." It must be admitted that that the author has fairly attained to his ideal. His explanations are so clear, and his facts and principles so interesting, that they will be sure to engage the attention of ordinary readers, while at the same time he gradually passes to the consideration of questions and the presentation of views that will appeal to instructed critics as new contributions to the subject.

Another point in regard to this work strikes us as most important. It is largely a book of experiments; the effects discussed and illustrated with the woodcuts are such as can be tested by the reader who will take some pains to practice. This is an important means of education, by which the reader not only learns how to do things, but becomes acquainted with the subject at first hand, and knows what he knows. On this feature of his book. Dr. Le Conte remarks "As a means of scientific culture, the study of vision seems to me exceptional. It makes use of, and thus connects together, the sciences of physics, physiology, and even psychology. It makes the cultivation of the habit of observation and experiment possible to all; for the greatest variety of experiments may be made without expensive apparatus, or, indeed, apparatus of any kind. And, above all, it compels one to analyze the complex phenomena of sense in his own person, and is thus a truly admirable preparation for the more difficult task of analysis of those still higher and more complex phenomena which are embraced in the science of psychology."

Radical Club was founded in the spring of 1867, with the purpose of bringing together occasionally a few persons who were known to be daring thinkers on subjects of high import, and of furnishing them "an opportunity for uttering their thought to an audience capable of appreciating its scope, of criticising its worth, and of developing its relations." It was composed of members of all religious denominations, and enjoyed an attendance of two hundred at the closing sessions of 1880. This volume contains about fifty of the essays which were presented at the meetings, with notices of the discussions which followed the reading. The authors, whose names are appended, are, as a rule, men and women known in literature, science, or the forum, whose words never fail to command attention. The subjects of their papers represent a wide range of thought in literature, art, theology, metaphysics, science, and sociology, and are of degrees of practicality of which "Color blindness" may be taken to represent one extreme and "The Impossible in Mathematics" the other. The reports of the informal discussions are full of conventional life, and are hardly less interesting than the essays.