Seeing that in the vast number of the nerves of the body the functions of sensation and motion were evidently combined, Bell imagined that these nerves consisted of different portions tied together, and he sought for a method of determining how they were combined. The separate portions in which the spinal nerves enter the spinal cord, forming two roots, anterior and posterior, occurred to him as furnishing a possibility of experimental inquiry. He now resolved to make crucial experiments on living animals, which should settle the question by a well-devised plan of procedure. No man was more averse to giving unnecessary pain than Charles Bell; no man felt more keenly the sufferings of his patients. The first brief record of the results is as follows: “Experiment 1. I opened the spine and pricked and injured the posterior filaments of the nerves—no motion of the muscles followed. I then touched the anterior division—immediately the parts were convulsed. Experiment 2. I now destroyed the posterior part of the spinal marrow by the point of a needle—no convulsive movement followed. I injured the anterior part, and the animal was convulsed.” It was at once inferred that the anterior root of the spinal nerves was motor in its functions, the posterior root sensory. This simple fact revolutionised the physiology of the whole subject. We cannot now realise the novelty which there was in attaining this extent of knowledge of the nervous system, or how valuable this firm basis was in commencing to unravel the nervous mechanism. We cannot here detail the experiments and trains of reasoning by which it was shown that the fifth cranial nerve was similar in its general plan to the spinal nerves, including distinct sensory and motor portions; and by which the knowledge of the cranial nerves generally was widely extended. We note now that Bell’s first paper on the Nervous System was read before the Royal Society on the 21st July 1821, and was received with great approbation. It soon became generally known throughout Great Britain and on the Continent, being by almost every one acknowledged as strikingly original. The dispute which afterwards arose as to his perfect originality and independence having been so conclusively settled in Mr. Bell’s favour by the production of his original pamphlet, manuscript and letters, no account of the controversy need here be given. He himself fully felt the importance of his discoveries: “I have made a greater discovery than ever was made by any one man in anatomy,” he says, not vaingloriously, but as a simple perception of the fact.