262 DIGESTIVE SYSTEM. 



separated, leaving what is called a tincture of bile. Gall-stones 

 are found to consist principally of a sort of spermaceti, that has 

 been used for soap to clean cloth with. The colour and notorious 

 bitterness of bile do not seem to be owing to the presence of 

 any thing peculiar ; but rather ascribable to some peculiarity of 

 arrangement of its component parts, which is not understood. 

 For if the tincture of bile is exposed to the air, it becomes white ; 

 or if nitric acid be dropped into it, that will likewise render it 

 white*. 



OF THE SPLEEN. 



The spleen or milt is a spongy viscus, of a pyramidal figure, 

 situated in the left hypochondrium, between the stomach and 

 false ribs. 



Colour. — Its colour is principally owing to the stagnant blood 

 in it. The surface possesses a blue mottled or marble hue, 

 which becomes reddened by exposure to air. It is much darker 

 interiorly — when its contained blood becomes exposed. 



Volume and Weight. — Though it vacies continually in its 

 volume, depending on the condition of the circulation through it, 

 it seldom or never exceeds three pounds in weight. 



Form. — The spleen is adapted in shape to the space in which 

 it is lodged ; being concave next the stomach, convex where it 

 is opposed to the ribs. It differs remarkably from the spleen of 

 the human subject in form ; for, instead of being oval in its cir- 

 cumference, and having an obtuse margin, it is elongated after 

 the form of a tapering pyramid, and at length terminates in a 

 point. 



Capsule. — It receives a complete capsular envelope from the 

 peritoneum, to the close fitting and intimate adhesion of which 

 it chiefly owes its feel of solidity and firmness : for, when strip- 

 ped of this tunic, its texture is discovered to be soft, lacerable, 

 and spongy, and to present all the appearances of glandular 

 arrangement ; and as such any one could not fail to regard 

 it who had not made himself previously acquainted with its 

 intimate structure. 



Structure. — It differs remarkably, however, from a gland, in not 

 having any excretory duct ; an appendage for which it has no 

 occasion, as it is not believed to perform any secretory function. 

 It is now generally supposed, that the arteries of the spleen, after 

 having spread their branches within its substance into innume- 

 rable ramifications, terminate in cells of a membranous composi- 

 tion, from which veins, about equivalent in number, take their 



* Aberncthv's Lectures in tlie Lnncct. 



