Excerpt from Report of the Director for the Year Ending October 31, 1924 It has heretofore been thought that too much protein in the ration injures the kidney. This, however, has not been con firmed by the experimental feeding of rats within the periods of time thus far studied. The kidneys, although enlarged, are not otherwise abnormal. It has also been found that a diet may be entirely adequate for vigorous growth over long periods, but still be deficient in some factor which determines fertility. This fact may become important in the feeding of farm animals Since it may later be discovered that the feeding of highly concentrated rations to high bred stock may be responsible for their lack of fertility. In connection with this brief summary of biochemical investiga tions mention must be made of the development of methods for preparing pure protein substances in large quantities which has been the basis of past experimentation. In feeding these products to animals it has been shown conclusively that some proteins are inadequate for proper growth and development, while others possessing known or unknown characteristics are amply sufficient. The ability to prepare large amounts of pure proteins provides a sure foundation for further investigation in this field. 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.