238 



THE CAT. 



[chap. vm. 



otlicr ductless glands arc the various lymphatic glands already- 

 spoken of ill the last chapter. 



§ 17. Another viscus, and one of large size, is akin in nature to 

 the lymphatic glands. This is a large ductless organ already men- 

 tioned as lying in the abdomen in the vicinity of the pancreas, close 

 to the left side of the stomach. It is called the spleen. It is some- 

 what variable as to shape and size, generally in the form of an 

 elongated triangle, somewhat bent on itself, of a dark bluish colour, 

 lying immediately behind the diaphragm. It is convex and smooth 

 on its left side and concave on the side which is applied to the 

 stomach, which is marked by a vertical fissure, called the /uIk.s, 

 where the vessels and nerves pass into and out from its substance. 



Besides the peritoneum, the spleen is invested with a fibrous and 

 very elastic coat which, at the hilus, is reflected into the body of 

 the viscus, forming sheaths and canals for the large blood-vessels 



s'. Wall (if stomach 



Fig. ns.— TuE Spleex. 



2)1/. ryloric iioiiion of stomach 



and nerves which ramify within it. Thus is formed a highly dis- 

 tensible framework composed of areolar tissue, with a large quantity 

 of elastic fibres. Amongst these elastic structures, with their 

 vessels, is the red pulpy substance of the spleen. This is formed of 

 nucleated and non-nucleated granular bodies, amongst which are 

 scattered numerous whitish vesicles, called Malpighian corpuscles of the 

 spleen, attached like buds to the sides of the minute branches of the 

 arteries, and each composed of a fibrous bag enclosing granular 

 nucleated corpuscles. 



The FUNCTION of the spleen is so far related to alimentation that 

 the organ begins to dilate while digestion progresses, reaching its 

 largest dimension after a meal ; while later, if no fresh food be 

 taken, it becomes reduced to its smallest size. A very remarkable 

 fact, however, about the spleen is that it can be entirely extirpated 

 without its loss producing any strikingly injurious effect. The 

 function usually attributed to it is that of helping to repleni.sli the 

 nutritious fluid by forming lym])li colls, which pass from it directly 

 into the blood. Much obscurity, hoN\'evcr, still remains as to the 

 entire part it plays in the activities of life, and as to what may be 

 really its main function. 



