222 SPECIAL ANATOMY. 



4. Vessels: a. Art. licnalis, branches of cadiaca, divides into four or five 

 twigs, each of which supplies one or the other independent parts of the spleen. 

 b. Ven. lienalis, the principal branch of the ven. porta, four or five times larger 

 than the Art., without valves, c. Lymphatics : they go into the glands along 

 the hilus, between the layers of lig. gastro-lienale. 



5. Nerves : come immediately from plex. lie't.nlis, as well as from pi Solaris. 

 Function : The preservation or alteration uf the blood or the lymph (?), 



according to Cruveilhier, makes up the chief substance of the spleen, as that 

 terminates in cells. 



452. The Peritonaeum, 



is a serous, (in the male) entirely closed sack, (in the female open 

 at the extremities of the Fallopian tubes,) which on the one hand 

 lines the abdominal walls, on the other partially invests the or- 

 gans which lie within them. These last are the organs of diges- 

 tion (below the diaphragm) and the female organs of generation. 

 But they do not lie within the cavity of the sac, but in folds on 

 the external surface of it. Quite unfolded, the sac would pre- 

 sent the appearance of a bladder, divided into a larger and smaller 

 (by a constriction), but which are connected together by an 

 opening at the place of constriction, and of which, the smaller 

 (saccus epiploicus, because it forms the omentum, epiploa) is 

 inverted into the larger. The place of constriction surrounds a 

 semicircular (or triangular) Ispace (foramen Winslowii}, one inch 

 in size, which is bounded before by the gall-ducts, behind by ven. 

 cava infer., below by duodenum, above by the neck of the gall 

 bladder, and is situated under the lobulus Spigelii. As the peri- 

 tonaeum passes upon the organs contained in the abdominal cavity 

 there become formed: 1. Folds (ligaments), e. g., such as lie 

 between two different viscera. 2. Mesenteries ; these are inver- 

 sions from the posterior abdominal walls which always consist of 

 two layers. 3. Omenta ; these are prolongations of laminae over 

 the organs. 



As the peritonaeum forms a closed sac, the description of it may 

 be commenced at any point. 



453. A. Peritonaeum abdominale. 



The walls of the abdominal cavity are lined all round by the 

 peritonaeum as with a sac, with the exception of those places on 

 the dorsal wall, at which inversions take place into the interior of 

 this sac, for the purpose of surrounding the viscera with a par- 

 ticular envelope (compare Pleura), and thus to form the Peri- 

 tonaeum viscemle. The internal surface of this parietal layer 

 looks into the cavity of the sac, is smooth and slippery like the 

 visceral layer, which is turned to it. The external surface is 

 rough, loosely attached by uniting tissue to the internal surface of 



