62 ORGANS OF DIGESTION. 



shallow fossa, while the lower surface is projecting, and by 

 coming in contact with the transverse colon, tinges it with bile, 

 by transudation after death. 



The Gall Bladder has three coats, a peritoneal, a cellular, and 

 a mucous one. 



The Peritoneal Coat is not complete, but only covers that part 

 of the sac not received into th^ fossa on the under surface of the 

 liver; it is, therefore, a continuation of the peritoneal coat of the 

 latter; sometimes, however, the gall bladder is so loosely at- 

 tached to the liver that it almost hangs off from it, in which case 

 the peritoneal coat is nearly complete. 



The Second coat is condensed cellular, membrane. Through 

 it ramifies a great number of lymphatics, and blood vessels; be- 

 low, it attaches the peritoneal to the mucous coat, and above, 

 the latter to the liver. 



The Mucous Coat is always tinged of a deep green or yellow, 

 by the bile which it contains percolating after death; for it is 

 said to be, before that, of a light colour. This coat is thrown 

 into irregular tortuous folds or wrinkles of extreme delicacy, in 

 the intervals of which are many round or polyhedrous cells, 

 causing it to look, when floated in water, like a fine honey comb: 

 such as are about the fundus of the sac are superficial, and not 

 so distinct; but those near its middle and about the neck, are a 

 line or a line and a half deep. In the neck or apex, and in the' 

 beginning of the cystic duct, are from three to seven, sometimes 

 twelve, semilunar duplicatures of the internal membrane, which 

 also retard the flux and afflux of any fluid, though they do not 

 afford so much resistance to the ingress as to the egress of it. 

 These duplicatures are sometimes arranged into a spiral valve, 

 projecting from the inside of the duct, and forming two or three 

 turns.* Very small mucous follicles exist over the internal face 

 of this membrane, the discharge of which fills the gall bladder 

 when the secretion of bile has been interrupted by diseased ac- 

 tion, as in yellow fever, or by scirrhus of the liver. 



The artery of the gall bladder is a branch of the hepatic. 



* Discovered latterly by M. Amussat of Paris. M. Amussat has also detected 

 muscular fibres in the gall bladder and biliary ducts, in which we see an analogy 

 with other hollow viscera. Am. Med. Jour. Vol. ii. p. 193. 



