CHAP. XXI.] FUNCTIONS OF THE SYMPATHETIC. 147 



Looking to the anatomy of the nerve, there can be no doubt 

 that some fibres are derived from the spinal cord or medulla 

 oblongata, and that others proceed from the sympathetic ganglia. 

 The motor and sensitive fibres, and some of those going to the 

 other muscular parts, belong, no doubt, to the former class ; the 

 vascular, with the highest probability, to the latter. 



Valentin's experiments indicate that the roots of the encephalic 

 and spinal nerves exert considerable influence upon the movements 

 of parts supplied by the sympathetic. For instance, irritation of 

 the roots of the first three or four cervical nerves, excites increased 

 action of the heart; and that of the dorsal and lumbar spinal 

 nerves, stimulates the peristaltic action of the intestines through 

 the splanchnic nerves, and the abdominal plexuses. 



The effects of diseased states of the spinal cord also afford a sup- 

 port, which is more to be relied upon than the previous experi- 

 ments, to the opinion that the motor and sensitive fibres of the 

 sympathetic are implanted in the spinal cord. When there has 

 been extensive lesion of the cord, from injury or disease, the intes- 

 tinal canal is always affected to a degree proportional to the extent 

 of the lesion ; and this affection shows itself in the torpor of the 

 intestines, and the readiness with which they become distended by 

 flatus, giving rise to the tympanitic condition of abdomen, which so 

 generally attends disease or injury of the spinal cord. 



It had long been thought, that the sympathetic nerve plays an 

 important part in the sympathies of the body. Our improved 

 knowledge of the anatomical distribution of the nerves, and of 

 their physiological anatomy, and of their endowments) clearly shows 

 that the phenomena of sympathy are explicable by the known laws 

 of action of the great nervous centres, and that the sympathetic 

 nerve can take no more prominent part in it than any other nerve ; 

 the extent to which it or any other nerve may be engaged in the 

 play of such sympathies, being proportioned directly to the extent 

 of its central as well as its peripheral connections. 



It would be more consistent, therefore, with a scientific nomen- 

 clature, to discard the term Sympathetic as applied to this nerve ; 

 the old name Intercostal would, in some respects, be preferable. 

 There is, however, great difficulty in finding a name which would 

 adequately express its constitution and offices, which may be sum- 

 med up as follows : 



1. In its constitution it is compound, consisting of tubular fibres 

 and of gelatinous fibres. 



2. In its offices, it is a motor nerve to many of the internal 



L 2 



