CHAPTER IV. 



ON THE SITUATION AND STRUCTURE OF THE SPLEEN. 



SECT. 43. It hath at all times been matter of surprise 

 among the learned, that a viscus so large, and so advantage- 

 ously situated as the spleen is, added to the frequent oppor- 

 tunities of inspecting it in different states of health, should, 

 notwithstanding, have its uses so involved in obscurity, as to 

 elude the researches of so many ingenious and industrious 

 inquirers. 



SECT. 44. Not that the spleen has at any time been con- 

 sidered as useless, for at different periods a variety of different 

 offices have been assigned to it. Among the ancients, the 

 most celebrated opinion was, that it made the atra bilis or 

 succus melancholicus, which they supposed was carried by the 

 vasa brevia into the stomach ; but later observations have 

 entirely exploded that idea, insomuch that the very term is 

 almost extinct. And we shall endeavour to prove, that the 

 more modern opinion, of its producing some change on the 

 blood preparatory to the secretion of bile, hath no better 

 foundation in nature. 



SECT. 45. But it will be unnecessary to repeat the various 

 opinions that have been entertained at different times respect- 

 ing the use of this viscus. Our present endeavour will be to 

 describe its situation and structure, and afterwards to inquire 

 into some particulars respecting its use. 



SECT. 46. The spleen then forms the superior part of the 

 abdominal viscera on the left side ; its figure is rather oblong, 

 a little convex on its outer or upper, and a little concave on 

 its inner or lower side ; it is placed obliquely in the left hypo- 

 chondrium, with its convex surface exactly corresponding with 

 the concave or under surface of the diaphragm, to which it 

 sometimes adheres, but is always in contact with it, unless 

 when the left lobe of the liver extends very far over into the 



