186 NATURAL THEOLOGY. 



of the gall-bladder is such as to apply this struc- 

 ture to the best advantage. In its natural situation, 

 it touches the exterior surface of the stomach, and 

 consequently is compressed by the distention of 

 that vessel : the effect of which compression is to 

 force out from the bag, and send into the duodenum, 

 an extraordinary quantity of bile, to meet the ex- 

 traordinary demand which the repletion of the 

 stomach by food is about to occasion.* Cheselden 

 describesf the gall-bladder as seated against the 

 duodenum, and thereby liable to have its fluid press- 

 ed out by the passage of the aliment through that 

 cavity, which likewise will have the effect of caus- 

 ing it to be received into the intestine at a right 

 time and in a due proportion. 



There may be other purposes answered by this 

 contrivance, and it is probable that there are. The 

 contents of the gall-bladder are not exactly of the 

 same kind as what passes from the liver through 

 the direct passage. J It is possible that the gall 

 may be changed, and for some purposes meliorat- 

 ed, by keeping.''^ 



The entrance of the gall-duct into the duodenum 

 furnishes another observation. Whenever either 



■'^ On this passage some remaiks on the absence of the gall-blad- 

 der ill certain animals might be required ; but the reader may turn 

 to the note in the Appendix on the stomach of the horse. 



* Keill's Anat. p. 64. f Anat. p. 164. 



I Keill, (from Malpighius,) p. 63. 



