374 



termed the Ganglionic nerves, or those which enter ganglions, pro- 

 perly so called ; that term being limited to such protuberances only 

 as receive branches of nerves proceeding from the brain and spiral 

 cord. These nerves are distributed more especially to the vital or- 

 gans, as the thoracic and abdominal viscera, and to the muscles sub- 

 servient to their functions. The nerves belonging to this class also 

 convey impressions to the sensorium, and occasionally excite the 

 muscles of involuntary motion, which, in common with all muscles, 

 possess an inherent power of contractility dependent solely on their 

 own mechanism, and which in ordinary cases are excited by stimuli 

 peculiar to themselves. But the most important function of the gan- 

 glionic nerves, is that of supporting the processes of secretion and 

 assimilation, which require for their performance the combined influ- 

 ence of the whole brain and spinal cord. Viewed as a whole, the 

 system of ganglionic nerves, therefore, constitutes, in the strictest 

 sense, a vital organ. Thus the sensorium, though connected by 

 means of the cerebral and spinal nerves only partially with the organs 

 of sense and voluntary motion, is, by means of the ganglionic nerves, 

 connected generally with all the functions of the animal body. Hence 

 affections of the stomach and other vital organs extend their influence 

 over every part of the frame ; while those of a muscle of voluntary 

 motion, or even of an organ of sense, although possessing greater 

 sensibility, are confined to the injured part. 



From a due consideration of the phenomena of the nervous system, 

 it would appear that they imply the operation of more than one prin- 

 ciple of action. The sensorial power is wholly distinct from the ner- 

 vous power ; the former residing chiefly in the brain, while the latter 

 belongs equally to the spinal cord and brain, and may be exercised 

 independently' of the sensorial power. In like manner, the muscular 

 power resides in the muscles, and may be called into action by 

 various irritations independently of the nervous power, though fre- 

 quently excited by the action of that power. The muscles of volun- 

 tary motion are subjected to the sensorial power through the inter- 

 vention of the nervous system ; and those of involuntary motion are 

 also, under certain circumstances, capable of being excited through 

 the nerves by the sensorial power, particularly when under the influ- 

 ence of the passions. The same observation applies also to other 

 actions which properly belong to the nervous power, such as the 

 evolution of caloric from the blood, and the various processes of se- 

 cretion and of assimilation. That the nervous power is in these 

 instances merely the agent of other powers, and is independent of 

 the peculiar organization of the nerves, is proved by the same effects 

 being produced by galvanism, transmitted through conductors diffe- 

 rent from the nerves. The successive subordination of these several 

 powers is shown during death, when the sensorial functions are the 

 lirst to cease, and the animal no longer feels or wills, but yet the 

 nervous power still continues to exist, as is proved by the nerves be- 

 ing capable, when stimulated, of exciting contractions in the muscles, 

 both of voluntary and of involuntary motion,of producing the evolution 



