Excerpt from Hints for Teachers of Physiology The class may next be asked to point out a resem blance between the materials used for fuel and those used for food. Some pupil familiar with wood-burning locomotives will doubtless suggest that the materials are in both cases of regrettable origin. An opportunity will here be given to the teacher to explain that coal burning locomotives do not furnish an exception to this statement, since coal must be regarded as fossil wood grown upon the surface of the earth in former geological periods. 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.