Excerpt from Annual Report of the National Board of Health, 1880 IV. An investigation as to the best method of determining the amount and character Of organic matter in the air has been completed by Prof. Ira Remsen, of the Johns Hopkins University, of Baltimore, whose pre liminary report On the same subject has heretofore been transmitted to Congress in connection with the first annual report Of this Board. The final report is hereto appended, marked C. 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.