SECT. 1 66.] THE SRLEEN. — ENVELOPES AND TRABECULE. 359 



probably, also, to the secretion of the bile. With reference to its 

 structure, it consists of a, fibrous and serous envelope, and of a soft 

 parenchyma, which is principally composed of reticulated firm 

 trabecular, the splenic trabecular, and of a red substance enclosed 

 by them, the splenic pulp. In the latter, again, there are con- 

 tained numerous peculiar whitish bodies, the splenic corpuscles ; 

 and through the whole interior there are distributed numerous 

 vessels and a certain number of nerves. 



§ 166. Envelopes and Trabecular Tissue. — The peritoneal en- 

 velope covers the entire surface of the spleen, Avith the exception 

 of the hilus, whence it is continued to the fundus of the stomach, 

 over the splenic vessels and nerves, and has the name of the 

 gastro-splenic ligament. At the upper end, also, the peritoneum 

 is reflected as the lig. phrenieo-lienale, or suspensory ligament. 

 In man, but not in ruminant animals, the serous coat is so firmly 

 connected with the fibrous envelope, that it can only be pulled off 

 from the organ in shreds. 



The fibrous envelope {tunica fibrosa, albuginea, seu propria) 

 forms a complete investment to the spleen. Although very firm, 

 this coat is rather thin and transparent; at the hilus, it is 

 continued into the interior, and conducts the splenic vessels as far 

 as their finer ramifications : here it forms special sheaths, vagina 

 vasorum, similar to the capsule of Glisson in the liver. In man, 

 this exterior extension consists of ordinary connective tissue ; but in 

 certain animals, smooth muscular fibres, in considerable number, 

 have been demonstrated in my researches. I have seen these 

 fibres in the dog, pig, ass, and cat, but not in the rabbit, horse, ox, 

 hedgehog, porpoise, or bat. 



The trabecule of the spleen are white glistening fibres, flattened 

 or cylindrical, of an ave- Fig. 152. 



rage diameter of ^0" *° 

 f", which arise in great 

 numbers from the inner 

 surface of the fibrous 

 tunic, and also, though 

 more sparingly, from the 

 outer surface of the 

 sheaths of the vessels. 



TIipsp lippmnp nnitprl with Transverse section through the middle of the spleen of the 

 J. rn.su UCV/UUXC uuauu « 1111 0X) wa8hed , lUt in order t0 show the trabecul a3 and their ar- 



Similar trabecule in the ™»gement. Natural size. 



interior of the spleen, and form a network which extends through 



