t H. III.] THE VISCERAL NERVES. 95 



there are natural obstacles that prevent the transmission of the 

 impression to the brain (47); of these we shall treat in the 

 second part (428, 429) . In virtue of its sensibility, the stomach 

 is susceptible of impressions from conceptions in the brain (98), 

 which are sentient actions, as, for example, a violent pain causes 

 spasms of the stomach. The observations made with reference 

 to the action of the sensational conceptions and desires on the 

 oesophagus and intestinal canal, are equally applicable to the 

 stomach (170); they induce sentient actions, as, for example, when 

 by an imagination or anticipation of a loathing, its action is in- 

 verted, and vomiting is excited; or, when it is excited to motion by 

 hunger ; or is thrown into spasmodic action by violent emotions. 

 The will has little influence over it ; but the connection between 

 disorders of the mind and the nervous system, and disorder of 

 the digestive powers of the stomach and bowels, is well known. 



175. Although the sensibility of the liver is not great, and, 

 consequently, only few external impressions made on its nerves 

 reach the brain, still it is capable of sentient actions. They 

 are observable only in the most vivid external sensations and 

 sensational conceptions, as, for example, in the pain of inflam- 

 mation, or in rage, fury, &c., inasmuch as it can be inferred from 

 the bilious disorders which follow, as icterus, &c., that the 

 secretion of bile must be prevented or increased. The nerves 

 can also exercise an indirect influence on the liver through the 

 diaphragm, and the abdominal muscles, and the other organs 

 in relation with it, and the results are also sentient actions. 



176. The kidneys have but few nerves, and are only afi'ected 

 by powerful external impressions and sensations, as when there 

 is a stone or inflammation present ; in which cases only, certain 

 sentient actions occur, as spasms. The external impressions 

 made by the urine, and which excite vivid external sensations 

 in the nerves of the tongue, the nose, and even the skin itself, 

 are either not made at all on the renal nerves, or a natural 

 obstacle (47, &c.) prevents their transmission to the brain. 

 The urinary bladder, on the other hand, is much more sensitive. 

 Vivid external sensations (pain) cause spasms and spasmodic 

 discharge of urine, which are sentient actions. The sensational 

 conceptions and foreseeings act upon it, whence persons are 

 often induced to pass urine in dreams. The will has also some 

 influence upon it through the sphincters. 



