Excerpt from The Protozoa The Protozoa not only claim the interest of the professional naturalist, but also that of a wider circle of nature students who, with the aid of the microscope, have always found here a fascinating field for observation and research.. In writing the present volume, embodying a summary of the more recent discoveries concerning these minute animals, I have aimed to keep in mind the needs of the latter class of naturalists, as well as those who search more deeply in the unicellular organisms for the solution of many morpho logical problems which. Remain unsolved in the higher animals, or for vital processes which afford a transition from the manifestations of life in its simplest expression to life as seen in the lower forms of invertebrates. The subject-matter of the volume is treated from three points of view: (i) The historical. To which the first chapter is devoted. (2) The comparative, to which five chapters are given: one to the group of Protozoa as a whole, the other four to the main classes. (3) The general, to which three chapters are devoted. One of these is given to the phenomena of old age or senile degeneration in Protozoa and renewal of youth through the union of two individuals, and to the bearing of these phenomena upon sexual reproduction in general. Another is given to the special structures of nuclei and centrosomes of the Protozoa; this, the most technical chapter in the book, is introduced because of the growing importance which the Protozoa have in the problems of cellular biology, especially with those dealing with the origin of the division-centre and its aecom panying structures in the cells of the Metazoa. The last chapter is devoted to a consideration of the physiology of the Protozoa, with especial reference to the Protozoa as organisms endowed with the powers of coordination and of adaptation, which up to the present time have eluded physical and chemical analysis. 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.