OF MUSCULAR MOTION. 189 



299. This irritability, muscular power, or vis insita, 

 is bestowed upon all muscles, but in different degrees.* 



300. The highest order are the hollow muscles which 

 perform the vital and natural functions, and especially 

 the heart, (124) whose internal surface enjoys a very 

 lively and permanent irritability. 



Next to the heart follows the intestinal canal, parti- 

 cularly the small intestines, which, in warm-blooded 

 animals, contract after the heart has ceased to show 

 signs of irritability. 



Next the stomach. 



Then the urinary bladder, &c. 



Among the other muscles, the respiratory, v. c. the 

 diaphragm, the intercostals, and triangularis sterni, are 

 remarkable for their irritability. 



Then follow the remaining muscles. 



Less, but still however some, exists in the ar- 

 teries. (128) 



Also in the venous trunks contained in the thorax. (95) 



Still less, if it deserve the name of irritability, in the 

 other blood vessels. (132) 



301. Haller, the great arbitrator in the doctrine of 

 irritability, has ascribed it improperly (40, 5807), we 

 think, to some parts possessed indeed of contractility 

 t i - . . ^_* _ 



* See Haller on the irritable parts of the human body, Commenter. Soc, Sc. 

 Gotting. T. ii. and Nov. Commctitar. Cotting. T. iv. 



Among innumerable other writers on the same subject, suffice it to quote the 

 following : 



Zimmerman, De irritubilitate. Gott. 1751. 4to. 

 Oeder, on the same. Copenhagen. 1752. 4to. 



J. Eberh. Andrea;, on the same. (Frees. Ph. Fr. Gmclin.) Tubing. 1758. 4to. 

 Some others have been already mentioned, as well as three entire Collections 

 of Writers (p. 182.) 



