Excerpt from A Text-Book of the Theory and Practice of Medicine, Vol. 2 of 2: By American Teachers The infectious diseases are caused by pathogenic micro - organisms. The special characters of the micro-organisms which cause the infectious diseases considered in this work are described in the articles treating of these diseases. It is thought desirable to bring together in a separate article certain general considerations concerning infection. The most important advances in our knowledge of infectious diseases have come from the study of bacteria. Some knowledge of the general biology of bacteria is essential to an understand ing of pathogenic bacterial species and of their relations to disease. 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.