TEE ORGANS ANNEXED TO ABDOMINAL DIGESTIVE CANAL. 



505 



splenic artery, the same result will be arrived at. KoUiker has found in the 

 proper tunic of the spleen, and in its trabeculse, a particular contractile tissue — 

 the muscular cell-fibres — mixed with fasciculi of elastic or inelastic fibrous tissue. 

 (The proper coat, the sheaths of the vessels, and the trabeculse, consist of a dense 

 mesh of white and yellow elastic fibrous tissues, the latter considerably pre- 

 dominating. It is owing to the presence of this tissue that the spleen possesses 

 a considerable amount of elasticity, admirably adapted for the very great 

 variations in size that it presents in certain circumstances. In some of the 

 Mammalia, in addition to the usual constituents of this tunic, are found numerous 

 pale, flattened, spindle-shaped nucleated fibres, like unstriped muscular fibre. It 

 is probably owing to this structure that the spleen possesses, when acted upon by 

 the galvanic current, faint traces of contractility.) 



Splejiic pulp. — This name is given to a reddish pultaceous material, which 

 partly occupies the alveolar network formed by the intersections of the trabeculae. 

 It is sustained by a very delicate reticulum of connective tissue, and is composed 



Fig. 300. 



Fig. 301. 



A SINGLE SPr/.:NIC CORPUS- 

 CLE, FROM THE SPLEEN OF 

 THE OX. 



1, External tunic, or mem- 

 brana propria; 2, granular 

 contents ; 3, part of a small 

 artery ; 4, its sheath, de- 

 rived from the external 

 tunic of the spleen, with 

 which the corpuscle is 

 closely connected. 



BRANCH OF SPLENIC ARTERY WITH ITS RAMIFICATIONS 

 STUDDED WITH MALPIGHIAN CORPUSCLES. 



of numerous elements, such as pigment granules, free nuclei, large cells with 

 several nuclei, lymphoid elements, and blood-globules in a state of decomposition 

 or transformation. These globules are free or enveloped in an albuminoid 

 membrane. 



Malpighian corpuscles. — These are contained, like the splenic pulp, in the 

 meshes of the fibrous framework of the spleen, and are covered by that pulp. 

 Distributed on the course of the small arteries, these corpuscles, which are visible 

 to the naked eye, are little closed sacs of a wliitish colour. They are composed 

 of an adventitious tissue of arteries, in which are accumulated, at certain points, 

 lymphoid elements. They are, therefore, analogous to closed folHcles in then* 

 •structure. (The proper substance of the spleen consists of coloured and colourless 

 elements. The coloured are composed of red blood-corpuscles and coloured cor- 

 puscles, either free or included in cells. Sometimes unchanged blood-discs are 



