NERVOUS SYSTEM. 



97 



GANGLIONIC. 



CEREBRO-SPINAL. 



5. True Spinal, Excito-Motory or Reflex Nervous System^ Dr. 

 Marshall Hall 1 has proposed another division of the nervous system, 

 which is calculated to explain many of the anomalous circumstances; 

 we so frequently witness. He proposes to divide all the nerves into 



1. The cerebral or sentient and voluntary. 



2. The true spinal or excito-motory. 



3. The ganglionic or nutrient and secretory. 



If the sentient and voluntary functions be destroyed by a blow on 

 the head, the sphincter muscles still contract when irritated, because 

 the irritation is conveyed to the spine, and the reflex action takes place 

 to the muscle so as to throw it into contraction. But if the spinal 

 marrow be now destroyed, the sphincters remain entirely motionless ; 

 because the centre of the system is destroyed. Dr. Hall thinks, that 

 a peculiar set of nerves constitute, with the true spinal marrow as their 

 axis, the second subdivision of the nervous system ; and "as those of 

 the first subdivision are distinguished into sentient and voluntary, these 

 may be distinguished into excitor and motory. The first, or excitor 

 nerves, pursue their course principally from internal surfaces, charac- 

 terized by peculiar oxcitabilities, to the vesicular centre of the medulla 

 oblongata and medulla spinalis ; the second or motor nerves pursue a 

 reflex course from the medulla to the muscles, having peculiar actions 

 concerned principally in ingestion and egestion. The motions con- 

 nected with the first or cerebral subdivision are sometimes indeed 

 frequently spontaneous; those connected with the true spinal are, 

 he believes, always excited. Dr. Hall thinks that there is good rea- 

 son for viewing the fifth, and posterior spinal nerves as constituting an 

 external ganglionic system for the nutrition of the external organs ; 

 and he proposes to divide the ganglionic subdivision of the nervous sys- 

 tem into 1, the internal ganglionic, which includes that usually deno- 

 minated the sympathetic, and probably filaments of thepneumogastric; 

 and 2, the external ganglionic, embracing the fifth and posterior spinal 

 nerves. To the cerebral system he assigns all diseases of sensation, 

 perception, judgment, and volition, therefore all painful, mental, and 

 comatose, and some paralytic diseases. To the true spinal or excito- 



1 Lectures on the Nervous System, London, 1836, and American edit ,Philad., 1836. Also, 

 his Lectures on the Theory and Practice of Medicine, in the London Lancet for Feb. 3, and 

 Feb. 7, 1838. 



VOL. I. 7 



