LESSON XIX. 



THE SPLEEN. 



1. Piece of spleen of cat (ammonium bichromate 

 5 p.c.), cut at right angles to the long axis of the organ 

 including rather more than half of the transverse 

 surface. Note, with and without the aid of a lens, 

 the round whitish Malpighian corpuscles. Prepare 

 sections with the freezing microtome (cp. Less. vn.). 

 Stain some sections with picrocarmine and mount in 

 glycerine, others with haematoxylin and eosin or picric 

 acid and mount in balsam. Observe under a low 

 power 



Externally the broad fibrous sheath, the capsule, 

 sending in large and conspicuous trabeculae ; these 

 run throughout the spleen, branching as they go into 

 roundish bundles which are connected with other 

 similar bundles, and so form an irregular trabecular 

 network : the bars of the network cut in all directions 

 are scattered about the section. 



In many of the trabeculae, largish central spaces, 



