THE HORSE. 



Ill 



but bonds of connection between it and 

 other parts, such as the gastro-splenic omen- 

 tum, 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, aiid 

 in some parts, such as in the trabeculas, 

 Koelliker has found plain muscular fibres, 

 which he says do not exist in the external 

 portion of the fibrous tunic in the horse. 

 The covering not only envelopes 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 trabeculsB, 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 trabecular also arise 

 as processes from the vascular sheaths, as 

 well as from the external tunic. When the 

 pulp has been thoroughly washed, the outer 

 coat, with the trabeculse and sheaths, have 

 the appearance of a framework or skeleton. 



The splenic pulp has a medullary aspect, 

 being composed of cells and blood vessels ; 

 and if the organ be cut clean in any direc- 

 tion, ^^^e see, besides the cut ends of vessels 

 and trabeculsB, certain pearlish looking 

 bodies, named, from their discoverer, Malpig- 

 hian Corpuscles. If divided, fluid escapes 

 from the cavity which exists in their in- 

 terior. 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 ar- 

 terial trunks, if the pulp has been previously 

 carefully washed. 



The spleen derives its arterial blood 

 through the splenic artery, which is the main 

 division of the coeliac axis. Winding be- 

 tween the folds of the gastro-splenic omen- 

 tum, it not only sends numerous branches 

 through the hilum, and on to the surface of 



the spleen, but also supplies the stomach, 

 largely inosculating with the gastric artery, 

 so that the two might mutually perform 

 each other's office, if the main trunk of 

 either w*ere obstructed. 



The splenic vein is similarly distributed 

 to the artery, and it empties its blood into 

 the vena porta, just anteriorly to the pos- 

 terior mesenteric vein. 



The nerves of the spleen are derived from 

 the solar plexus, and with the splenic artery 

 enter the spleen. 



The lymphatics of the spleen are said by 

 Koelliker to be scanty; but Dr. Sharpey 

 tends rather to the belief that they are 

 abundant. They are arranged superficially 

 and deep, both sets anastomising freely 

 with each other, and, reaching the hilum, 

 they enter various scattered lymphatic 

 glands in the peritoneal folds, and then 

 empty into the receptaculum chyli. 



LIVER. 



The liver is the largest gland in the body, 

 and proportionately largest during certain 

 periods of foetal life. It is of a dark reddish 

 brown color, and destined for the office of 

 biliary secretion. 



It is situated across the long axis of the 

 body, in the right hypochondriac, epigastric, 

 and partly in the left hypochondriac regions. 



It is attached to various parts by five 

 ligaments, four of which are peritoneal 

 folds, and one is the remnant cord resulting 

 from the obliteration of the unbilical vein 

 within the abdomen. These attachments 

 will be more fully described with the peri- 

 toneal tunic. 



The external aspect of the liver is smooth, 

 being convex superiorly and concave inferior- 

 ly, broad posteriorly, and sharp anteriorly. 

 It .has a granular appearance, and a very 

 superficial inspection clearly shows that it is 

 composed of lobules, about the size of a 

 pin's head. 



The hepatic substance is irregularly 

 divided into numerous segments by fissures, 

 which either extend through the gland from 

 side to side, or are mere grooves of more 

 or less depth. The different segments of 



