CLASS II. 3. i. i. OF SENSATION. 271 



ORDO III. 



Retrograde Senfttive Motions. 



GENUS I. 

 Of Excretory Dufts. 



THE retrograde action of the osfophagus in ruminating ani* 

 mals, when they bring up the food from their firft ftomach for the 

 purpofe of a fecond maftication of it, may probably be caufed by 

 agreeable fenfation ; fimilar to that which induces them to fwal- 

 low it both before and after this fecond maftication ; and then 

 this retrograde action properly belongs to this place, and is er- 

 roneoufly put at the head of the order of irritative retrograde 

 motions. Clafs I. 3. I. 1. 



SPECIES. 



1. Ureterum motus retrogrejfus. When a (lone has advanced 

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

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

 the patient obtains fallacious eafe, till the ftone is again puflied 

 into the ureter. 



2. Urethra motus retrogrejffus. There have been inftances of 

 bougies being carried up the urethra into the bladder moft prob- 

 ably by an inverted motion of this canal ; for which fome have 

 undergone an operation fimilar to that for the extraction of a 

 ftone. A cafe is related, in fome medical publication, in which 

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

 ing many weeks, was voided piece-meal in a femi-diflblved ftate. 

 Another cafe is related of a French officer, who ufed a leaden 

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

 was, by injecting crude mercury, amalgamated and voided. 



In the fame manner the infection, from a fimple gonorrhcea, 

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

 fmall ftones frequently defcend fome way into the urethra, and are 

 again carried up into the bladder by theinverted action of this canal. 



3. Duff us choledocki motus retrogrejffus. The concretions of 

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

 violent pain for fome 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-ftone gives great pain, by its re- 

 trograde fpafmodic action ? See Clafs I. i. 3. 8. 



M. M. Opium a grain and half. 



72* 



