II. 3. 1. 1. OP SENSATION. 271 



ORDO III. 



Retrograde Sensitive Motions. 



GENUS I. 

 Of Excretory Ducts. 



THE retrograde action of the oesophagus in ruminating ani- 

 mals, when they bring up their food from their first stomach for 

 the purpose of a second mastication of it. may probably be caused 

 by agreeable sensation; similar to that which induces them to 

 swallow it both before and after this second mastication; and 

 then this retrograde action properly belongs to this place, and is 

 erroneously put at the head of the order of irritative retrograde 

 motions. Class I. 3. 1. 1. 



SPECIES. 



1 . Ureterum motus retrogressus. When a stone has advanced 

 into the ureter from the pelvis of the kidney, it is sometimes lia- 

 ble to be returned by the retrograde motion of that canal, and 

 the patient obtains fallacious ease, till the stoue is again pushed 

 into the ureter. 



2. Urethras motus retrogressus. There have been instances of 

 bougies being carried up the urethra into the bladder most pro- 

 bably by an inverted motion of this canal; for which some have 

 undergone an operation similar to that for the extraction of a 

 stone. A case is related, in some medical publication, in which 

 a catgut bougie was carried into the bladder, and, after remain- 

 ing many weeks, was voided piece-meal in a semi-dissolved state. 

 Another case is related of a French officer, who used a leaden 

 bougie; which at length found its way into the bladder, and was, 

 by injecting crude mercury, amalgamated and voided. 



In the same manner the infection, from a simple gonorrhoea, 

 is probably carried further along the course of the urethra; and 

 small stones frequently descend some way into the urethra, and are 

 again carried up into the bladder by the inverted action of this ca- 

 nal. 



3. Ductus choledochi motus retrogressus. The concretions of 

 bile, called gall-stones, frequently enter the bile duct, and give 

 violent pain for some hours; and return again into the gall-blad- 

 der, by the retrograde action of this duct. May not oil be car- 

 ried up this duct, when a gall-stone gives great pain, by its re- 

 trograde spasmodic action? See Class I, 1,3. 8, 



M. M. Opium a grain and a half 



