596 report — 1878. 



more blood. This same small filament of nerve is galvanized, and the reversal of 

 the above phenomena is found to take place. To some this observation is not only • 

 a mere meaningless juggler's trick, but a cruel one. To others it is a key which 

 opens a chamber full of treasures. It is like a newly-discovered isthmus or bridge 

 uniting two vast continents — that of the circulatory system with that of the ner- 

 vous system. In this controlling power of the nerves over the calibre of the blood 

 vessels lies the explanation of many of the most interesting phenomena which go on 

 within us. The burning flush of shame, the cheek blanched with fear, the sudden 

 activity of glandular secretion, as when an emotion of the mind causes tears to 

 flow, or salt placed on the tongue causes the secretion of saliva. The activity of 

 the brain in our waking moments, its death-like inactivity during sleep, the regula- 

 tion of our temperature, etc., are, within the limits of health, phenomena connected 

 with this controlling power of the sympathetic nervous system. Within the 

 domain of disease, its applications are without end or number ; from the sympa- 

 thetic and often painful swelling of the milk glands (hardly to be regarded as a 

 morbid action) to the condition of the blood-vessels of the brain which causes the 

 dreaded convulsive seizure of epilepsy, this dominion of the sympathetic nervous 

 system over the blood-vessels has a meaning and a practical importance. 



It would be unjust to others to say that Claude Bernard was the sole discoverer 

 of this vasomotor nervous system, as it is called. It would be equally unjust to 

 his memory not to admit that his researches had a large share in this discovery. 

 Pourfour du Petit and Dupuy had no doubt, long since divided the cord of the 

 Teat sympathetic nerve in .the neck, and noticed some of its consequences. But 

 the real discovery of the vasomotor nervous system was reserved for our time. 

 The illustrious physiologist (Dr. Brown-Sequard) who now fills the chair in the 

 College de France, rendered famous by such predecessors as Bernard, Magendie, 

 and Laennec, has no small share in this discovery, and, as regards its application 

 to the explanation of the phenomena of disease, and its treatment, has accom- 

 plished more than any of his predecessors. We owe to Bernard the discovery of 

 the principal results due to division of the cervical portion of the sympathetic 

 nerve ; assuredly the discovery is one in which experimental physiology has reason 

 to triumph, for it must be regarded as one of the most valuable disclosures of 

 modern science. It cements together the vast number of isolated facts which, 

 since the days of Prochaska and Robert Whytt, have been accumulating upon the 

 hands of physiologists, but which, in the length and breadth of their importance, 

 even Marshall Hall himself did not appreciate. But let us turn to the other half 

 of this experiment ; let me remind you that Dr. Brown-Sequard in America, Pro- 

 fessor Claude Bernard in Paris, and Dr. Augustus Waller in England, almost 

 simultaneously observed that galvanization of the divided sympathetic is followed 

 by a reversal of all the phenomena which have been already noticed to follow its 

 division — the vessels contract, heat diminishes, secretion is checked. These experi- 

 ments are illustrative of the influence of the nervous system over the vascular. 

 They have formed the basis of physiological theories very widely differing from 

 each other, and perhaps less striking but not less valuable experiments bearing on 

 the same subject. The muscular tunic of the vessels which ramify through the 

 body places them under the control of the nervous system as completely as is 

 the heart itself. As the muscular structure of the heart, so the muscular structure 

 of the vessels is subject to emotional and reflex influences. It is not only the 

 blood-vessels of the cheeks which blush. The greater development of the muscular 

 tunic in the vessels of glands and of the brain, shows that in those situations the 

 arrangements for controlling the blood supply are even more complete than else- 

 where. It is true that it has long been known that intimate relations exist between 

 organs more or less remote from each other. The term sympathy has long been in 

 use, and equally applied to the healthy functional activity as to the pathological 

 disturbances of organs distinct from each other. In the eyes of the practitioner, 

 the morbid sympathies (or reflex disturbances), such as occur in teething children, 

 or, later in life, from irritation of the gastro-intestinal or genito-urinary systems, 

 etc., have naturally eclipsed in interest the normal physiological sympathies, such 

 as that between the uterus and mammary gland, the mucous membrane of the 

 tongue and the salivary glands, etc. But be it remembered that they are closely 



