CAPSULE RENALES. 525 



the vessels contained in that duplicature. A second spleen (lien 

 succenturiatus) is sometimes found appended to one of the branches 

 of the splenic artery, near to the great end of the stomach ; when it 

 exists, it is round and of very small size, rarely larger than a hazel- 

 nut. I have seen two and even three of these bodies. The spleen 

 is invested by the peritoneum and by a tunica propria of yellow 

 elastic tissue, which enables it to yield to the greater or less disten- 

 sion of its vessels. The elastic tunic forms sheaths for the vessels 

 in their ramifications through the organ, and from these sheaths 

 small fibrous bands are given off in all directions, which become at- 

 tached to the internal surface of the elastic tunic, and, constitute the 

 cellular framework of the spleen. The substance occupying the 

 interspaces of this tissue is soft and granular, and of a bright red 

 colour ; in animals it is interspersed with small, white, soft corpus- 

 cules. 



Vessels and Nerves. The Splenic artery is of a very large size 

 in proportion to the bulk of the spleen ; it is a division of the coeliac 

 axis. The branches which enter the spleen are distributed to dis- 

 tinct sections of the organ, and anastomose very sparingly with 

 each other. The veins by thin numerous dilatations constitute the 

 principal part of the bulk of the spleen ; they pour their blood into 

 the splenic vein, which is one of the two great formative trunks of 

 the portal vein. The lymphatics are remarkable for their number 

 and large size, they terminate in the lumbar glands. The nerves 

 are the splenic plexus, derived from the solar plexus. 



THE SUPRA-RENAL CAPSULES. 



The supra-renal capsules are two small yellowish and flattened 

 bodies surmounting the kidneys, and inclining inwards towards the 

 vertebral column. The right is somewhat three-cornered in shape, 

 the left more semilunar ; they are connected to the kidneys by the 

 common investing cellular tissue, and each capsule is marked upon 

 its anterior surface by a fissure which appears to divide it into two 

 lobes. The right supra-renal capsule is closely adherent to the pos- ^ i 

 terior and under surface of the liver, and the left lies in contact witlj,, 

 the pancreas. Both capsules rest upon the crura of the diaphragrjiX' 

 on a level with the tenth dorsal vertebra, while by their inner bordg^ 

 they are in relation with the great splanchnic nerve, and with 

 semilunar ganglion. They are larger in the fetus than in the a 

 and appear to perform some office connected with embryonic 

 The anatomy of these organs in the foetus will be found in 

 ceeding chapter. 



In structure they are composed of two substances, c 

 medullary. The cortical substance is of a yellowish colouj^ahd 

 consists of straight parallel fibres placed perpendicularly side by 

 side. The medullary substance is generally of a dark brow^^lour, 

 double the quantity of the yellow substance, soft in tex^ey-' and 

 contains within its centre the trunk of a large vein the vena supra- 



