Excerpt from The Natural History of Aquatic Insects The conditions of life in fresh waters are materi ally different from those afforded by the sea. The chemical difference between fresh and salt waters is of small importance in itself - so small that many animals have been able to adapt themselves gradually to a change from one to the other. A degree of saltness far greater than that of sea-water is perfectly compatible with animal life, as is shown by the fact that Crustacea and Insects are often found quite at home in brine-pits and vats. There are even a few animals, like the Salmon, which can pass sud denly from fresh water to salt, or from salt to fresh. 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.