228 



ELEMENTS OF HISTOLOGY. [Chap. xxix. 



venous branches passing in the big trabeeulae to the 

 hilum. The venous sinuses in man and ape possess a 

 special adventitia formed of circular elastic fibrils. 

 Not all arterial branches are ensheathed in 



Fig. 132. From a Section through the Spleen of a Guinea-pig ; the 

 Blood-vessels had been injected (not shown in the figure). 



a, Artery of Malpighian corpuscle ; 6, pulp ; between its cells are the minute 

 blood-channels opening mtoc, the radicles of the veins. (Atlas.) 



Malpighian corpuscles ; some few fine arterial branches 

 open directly into the spaces of the pulp matrix, being 

 invested in a peculiar reticular or concentrically ar- 

 ranged cellular tissue (not adenoid). These are the 

 capillary sheaths of Schweigger Seidel. 



299. The blood passes then from the arterial 

 branches through the capillaries of the Malpighian 



