2f> ESSAY ON THE DESCRIPTIVE ANATOMY OF THE 
The margin of the spleen is sharp all round. The size of the 
organ varies considerably in different subjects, and, according to 
circumstances, in the same animal. 
The spleen is related, by its superior surface, to the left end 
of the greater curvature of the stomach, and to the diaphragm ; 
at its broad base it is in close relation with the left kidney; 
Its inferior surface is connected with both double and single 
portions of the colon. 
The spleen has two coats, a parenchyma, bloodvessels, nerves, 
and lymphatics, needing separate description. 
The external coat is peritoneum, which forms not only a 
covering to the organ itself, but bonds of connexion between it 
and other parts, such as the gastro-splenic omentum, and the 
attachment to the kidney and transverse colon heretofore 
described. This coat is smooth externally, rather closely 
attached to the fibrous coat internally, but of considerable 
elasticity, so as to allow the spleen sufficient freedom for 
distention. 
The second or fibrous coat, also termed the albugineous or 
elastic coat, is that closely applied to the parenchyma of the 
organ. It consists of yellow and white fibres, and in some 
parts, such as in the trabeculae, Koelliker has found plain mus¬ 
cular fibres, which he says do not exist in the external portion 
of the fibrous tunic in the horse. The covering not only enve¬ 
lopes the outer surface of the organ, but sends sheaths and 
processes into its substance. The sheaths are purposed for 
covering vessels, whilst the processes, termed also trabeculae, 
divide the substance of the spleen into areolae or interspaces, 
which contain a red matter, easily washed and pressed out, 
known as the splenic pulp. The trabeculae also arise as pro¬ 
cesses from the vascular sheaths, as well as from the external 
tunic. When the pulp has been thoroughly washed, the outer 
coat, with the trabeculae and sheaths, have the appearance of a 
framework or skeleton. 
The splenic pulp has a medullary aspect, being composed of 
cells and bloodvessels; and if the organ be cut clean in any 
direction, we see, besides the cut ends of vessels and trabeculae, 
certain pearlish looking bodies, named, from their discoverer, 
Malpighian Corpuscles. If divided, fluid escapes from the cavity 
which exists in their interior. They are perfectly visible to the 
naked eye, being about one-thirtieth of an inch in diameter, and 
with a pocket glass they may be seen attached to the small 
arterial trunks, if the pulp has been previously carefully 
washed 
The spleen derives its arterial blood through the splenic 
arterv, which is the main division of the cceliac axis. Winding 
