Excerpt from Second Book in Physiology and Hygiene All cells are active workers; and each has its special work to do. The human body may be aptly compared to a community made up of multitudes of individuals. In most communities there are various classes of workers - carpenters, blacksmiths, jewellers, chemists, merchants, teachers, etc. In the body, likewise, there is a division of labor. Some cells build, others tear down. Some cells may be compared to artists, others do the work Of scavengers. Some construct solid parts, others make the various fluids to be employed in the body or to be removed from it. Some act as sentinels, to give the body warning of danger; others defend it when attacked by the enemies of life or health. All labor together in the most perfect harmony when their work is not in any way interfered with. 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.