Excerpt from A d104 Book Physiology, Vol. 3 By 'afi'erent' nerve fibres we mean nerve fibres which in the body usually carry impulses from peripheral organs to the central nervous system. A very common effect of the arrival at the central nervous stem of impulses passing centripetally along afferent fibres is teget change in consciousness which we call a sensation hence afl'erent fibres are often called 'sensory' fibres, and the nervous impulses pusing cenrezijpetally along them, sensory im pulses. But as we have al y in part seen, and as we shall shortly see in greater detail, the central nervous system may be afl'ected by centripetal impulses, and that in several ways, quite apart from the development of any such change of consciousness as may be fairly called a sensation. We shall see reason for thinking that centripetal impulses reaching the spinal cord, and indeed other parts of the central nervous system, may modify reflex or automatic or other activity without necessarily g1ving rise to a sensation. Hence it is advisable to reserve the terms efl'erent' and afl'erent as more general modes of expression than motor or sensory.' 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.