PARALLEL PATHS _All Rights Reserved_ PARALLEL PATHS A STUDY IN BIOLOGY, ETHICS, AND ART BY T. W. ROLLESTON “Il faudrait, en un mot, suivre la grande route si profondément creusée ... mais il serait nécessaire aussi de tracer en l’air un chemin parallele, une autre route, d’atteindre les en deça et les après, de faire, en un mot, un naturalisme spiritualiste; ce serait autrement fier, autrement complet, autrement fort.” J. K. Huysmans. LONDON DUCKWORTH & CO. 3, HENRIETTA STREET, COVENT GARDEN 1908 PREFACE In a recent work by an eminent man of science, Dr. J. Reinke, Professor of Botany at the University of Kiel, there occurs a passage which I cannot do better than place in the forefront of this book as an indication of its aim. “Physiology,” writes Professor Reinke, “has become the study of the movements which, taken together, make up life. There is no manner of doubt that nourishment, metabolism,[1] reproduction, development, and sensation rest on processes of movement which depend on material systems of peculiar molecular conformation. For the bodies of plants and of animals are material systems whose conformation is of a most intricate character. “So far as physiology has at present advanced in the analysis of these phenomena of movement, their problems have fallen naturally into two groups. The first of these groups of phenomena is comparatively transparent, and stands in agreement with the general processes of the material world; it can be investigated by observation and experiment. We may, therefore, hope to decipher it completely, and to reduce it, in the end, to chemico-physical processes. Of this kind are the phenomena of nutrition, taking that word in its widest sense. But behind these processes there stand the facts of development and of reproduction, and here, in all investigations, and in spite of every attempt to demonstrate a basis of physical energy, research finds itself confronted by an _X_, a factor which mocks every effort to explain it by physics or chemistry. And this _X_ which lurks in all the phenomena of development takes a part in the nutritive processes also; so essential a factor does it appear in all the processes of life that chemical and physical forces alone would not suffice to keep alive even the most rudimentary of organisms, not to mention creating such an organism out of non-living chemical constituents.”[2]