The Croonian Lecture—On the results of the method introduced by the author of investigating the nervous system, more especially as applied to the elucidation of the functions of the pneumogastric and sympathetic nerves

Dr. Waller commenced by stating that he had been long engaged in the investigation of the nervous system by means of the method which he introduced many years ago. After drawing attention to the importance of the functions of the nervous system as the seat of all the higher faculties which distinguish animals from plants and man from the lower animals, he referred briefly to the general constitution and intimate structure of the nervous system. It is known that after a nerve has been disconnected from the central organs, its medullary part undergoes a series of changes. The tubular medulla, or white substance, is disintegrated and finally converted into dark granular matter. On this alteration the author founded his method of investigation, as it enables the inquirer to distinguish the altered from the sound fibres at any point of their course. Dr. Waller soon applied his method to the study of the sympathetic nerve, and was enabled thereby to clear up a great part of the mystery which hung over the origin and functions of this nerve—a nerve which supplies and presides over some of the most important organs in the body, the liver, the intestines, the womb, and especially the blood-vessels. In this manner, while associated with Dr. Budge, the author determined the part of the spinal cord termed by them the cilio-spinal region, which, through the part of the sympathetic connected with it, governs the dilating fibres of the iris. In the hands of Prof. C. Bernard, Brown-Sequard, Dr. Waller, and other the results obtained in this inquiry have shown the relation of the spinal cord to the important functions which the sympathetic nerve exercises in regulating the supply of blood in the vessels and, as a consequence, in controlling the general nutrition and temperature of the body.