THE SPLEEN. 209 



the organ becoming turgid with blood, the capsule is distended ; 

 and limits, by its resisting power, the degree of tumefaction to 

 which the spleen is liable. When the disturbing cause has again 

 passed away, and the circulation is about to return to its ordinary 

 condition, the elasticity of the capsule in the herbivora, and its con- 

 tractility in the carnivora, compress the soft vascular tissue within, 

 and reduce the organ to its original dimensions. This contractile 

 action of the invested capsule can be readily seen in the dog or 

 the cat, by opening the abdomen while digestion is going on, 

 exposing the spleen and removing it, after ligature of its vessels. 

 When first exposed, the organ is plump and rounded, and presents 

 externally a smooth and shining surface. But as soon as it has 

 been removed from the abdomen and its vessels divided, it begins 

 to contract sensibly, becomes reduced in size, stiff; and resisting to 

 the touch ; while its surface, at the same time, becomes uniformly 

 wrinkled, by the contraction of its muscular fibres. 



In its interior, the substance of the spleen is traversed everywhere 

 by slender and ribbon-like cords of fibrous tissue, which radiate 

 from the sheath of its principal arterial trunks, and are finally 

 attached to the internal surface of its investing capsule. These 

 fibrous cords, or trabeculse, as they are called, by their frequent 

 branching and mutual interlacement, form a kind of skeleton or 

 framework by which the soft splenic pulp is embraced, and the 

 shape and integrity of the organ maintained. They are composed 

 of similar elements to those of the investing capsule, viz., elastic 

 tissue and involuntary muscular fibres, united with each other by 

 a varying quantity of the fibres of areolar tissue. 



The interstices between the trabecube of the spleen are occupied 

 by the splenic pulp; a soft, reddish substance, which contains, 

 beside a few nerves and lymphatics, capillary bloodvessels in great 

 profusion, and certain whitish globular bodies, which may be re- 

 garded as the distinguishing anatomical elements of the organ, and 

 which are termed the Malpighian bodies of the spleen. 



The Malpighian bodies are very abundant, and are scattered 

 throughout the splenic pulp, being most frequently attached to the 

 sides, or at the point of bifurcation of some small artery. They 

 are readily visible to the naked eye in the spleen of the ox, upon a 

 fresh section of the organ, as minute, whitish, rounded bodies, which 

 may be separated, by careful manipulation, from the surrounding 

 parts. In the carnivorous animals, on the other hand, and in the 

 human subject, it is more difficult to distinguish them by the un- 

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