Excerpt from The American Journal of Physiology, Vol. 38 A correct estimation of the volume of the respiratory dead space is of fundamental importance in connection with many of the prob lems of the regulation of breathing and related topics. The interpreta tion of the data accumulated by many investigators depends upon the decision of the question whether the dead space is a fixed or a variable quantity. If the latter is the case, what are the nature, cause, and mode of control of such variations? Although earlier investigators recognized the dead space as a factor in to have been the first to report a measure ment of it. By means of a plaster cast of the cavity of the mouth, pharynx, trachea, bronchi and bronchioles of a cadaver he found a vol ume of 144 cc. He noted, however, that in the living subject even in an expiration much smaller than the volume of the dead space there are always to be found-considerable amounts of co2, and that as expira tion progresses the percentage of C02 in successive portions increases gradually, not abruptly: facts which later investigators have not always kept in mind. 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.