Excerpt from The Retrospect of Practical Medicine and Surgery, Vol. 11: Being a Half-Yearly Journal, Containing a Retrospective View of Every Discovery and Practical Improvement in the Medical Sciences, January-June, 1845The incident action of the nerves on the spinal cord and brain, whether in exciting or paralysing, has long been known. Whytt inferred, from some experiments with opium on frogs and dogs, that not only those nerves, to which opium is immediately applied, are rendered incapable of performing their office, but that the brain, spinal marrow, and whole nervous system are affected in the same manner, solely by the action of the opium on the nerves which it touches. For its effects upon dogs are too instantaneous to allow of the supposition, that the more subtile parts of this poison are re ceived into the blood, and by that means are conveyed to the brain, and in frogs, after the heart is taken out, and consequently a stop put to the circulation, yet a solution of opium, injected into the stomach and intestines, has the same effect, as when these animals are entire. We quote from his Remarks on the Sympathies of the Nerves, ' and he details many sympathies of the nerves, as, for exanmle, the contraction of the pupil is not owing to light acting as a stimulus on the iris, but solely to the sympathy between this membrane and the retina, or in Hallian phraseology, the retina is incident excitor to the motor nerve of the iris. And it is to be ob served, that although he does not explain, nor attempt to explain, the mode in which this sympathy or connexion in function occurs, he makes no error in the classification of his facts. The principle of irradiation of sensation will explain them all.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.