SECRETION. 



321 



gliian corpuscles of the spleen, and are situated on the sheaths of the 

 minute splenic arteries, of which, indeed, they may be said to be out- 

 growths (fig. 229). For while the sheaths of the larger arteries are con- 

 structed of ordinary connective tissue, this has become modified where 

 it forms an investment for the smaller vessels, so as to be composed of 

 adenoid tissue, with abundance of corpuscles, like lymph-corpuscles, 

 contained in its meshes, and the Malpighian corpuscles are but small 

 outgrowths of this cytogenous or cell-bearing connective tissue. They 

 are composed of cylindrical masses of corpuscles, intersected in all parts 

 by a delicate fibrillar tissue, which, though it invests the Malpighian 

 bodies, does not form a complete capsule. Blood-capillaries traverse the 

 Malpighian corpuscles and form a plexus in their interior. The struc- 



? .ste( ; f*s 



:f'^ 

 7.-v: v &$:;* 

 '.::.:. ; >>... 



Fig. 229. Section of spleen of cat. a, a', Malpighian corpuscles, in case of a', in connection 

 with small artery, 6; 6, &', small arteries; c, section of trabeculee. 



ture of a Malpighian corpuscle of the spleen is, therefore, very similar to 

 that of lymphatic-gland substance. 



Functions. With respect to the office of the spleen, we have the fol- 

 lowing data: (1.) The large size which it gradually acquires toward 

 the termination of the digestive process, and the great increase observed 

 about this period in the amount of the finely-granular albuminous 

 phisma within its parenchyma, and the subsequent gradual decrease of 

 21 



