chap, xvii.] ABDOMINAL NERVES. 369 



It may be well understood that an impression brought 

 to bear upon nerve centres of such extent and with 

 such important relations would produce considerable 

 effects. These effects we see in the profound collapse, 

 vomiting, and other grave symptoms that attend 

 severe injuries to the viscera, and especially to those 

 that are the most directly associated with these large 

 centres. The descending colon and sigmoid .flexure 

 are supplied by the inferior mesenteric plexus, a cord 

 that has but an indirect connection with the solar 

 plexus ; and this fact may serve to account for the 

 less serious symptoms often seen in strangulation of 

 the colon when compared with a like lesion of the 

 small gut. The upper part of the colon, although 

 supplied by the superior mesenteric plexus, is only 

 supplied by that part of it that is most remote from 

 the great centres, and it is. a conspicuous fact that 

 the nearer the lesion is to the stomach, the graver, 

 other things being equal, are the nervous phenomena 

 produced. It would appear that some lesion of these 

 nerve plexuses is sometimes active in producing a 

 remarkable pigmentation of the skin. This is seen 

 in Addison's disease, a disease marked by a general 

 bronzing of the surface, and usually associated with 

 some disintegration of the suprarenal capsules. The 

 very direct relation of these bodies to the solar plexus 

 is well known. In pregnancy also, in abdominal 

 tuberculosis, in cancer of the stomach, and in liver 

 diseases, a pigmentation of the face is sometimes seen, 

 that may in such instances be probably ascribed to a 

 disturbance of the great abdominal nerve centres. 



In some diseases of the liver and stomach " sympa- 

 thetic " pains are complained of between the shoulders 

 or about the inferior angles of the scapulae. These 

 parts are supplied with sensation by the fourth, fifth, 

 and sixth dorsal nerves. The great splanchnic cord 

 can probably explain the peculiar seat of these pains, 

 y 4 



