174 PRACTICAL MICROSCOPY. 



The fibrous capsule which envelopes the spleen sends trabeculae 

 within, which form a framework; and from this fibrils are sent off 

 which branch, broaden, and inosculate to form t/ie venous chambers of 

 the pulp. 



The arteries are frequently surrounded by nodules of adenoid tissue, 

 sometimes globular, more frequently considerably elongated, and fol- 

 lowing the vessel for a considerable distance. These nodules are 

 called Malpighian bodies. They bear no resemblance to similarly 

 named structures in the kidney, excepting, perhaps, when seen in 

 transverse section by the naked eye. 



The spleen will thus be seen to consist of a fibrous trabeculated 

 framework, the pulp, blood-vessels, and more or less isolated nodules 

 of adenoid tissue. 



PKACTICAL DEMONSTKATION. 



The organ must be absolutely free from decomposition. If human 

 tissue cannot be obtained in good condition, recourse may be had to 

 the ox, which will provide an excellent substitute. The small super- 

 numerary spleens, not infrequently found during post-mortem work, 

 are most desirable, as sections can be easily made through the entire 

 organ. 



Pieces of tissue half an inch cube, including a portion of the cap- 

 sule, should be hardened as directed for lymph nodes. Sections are 

 easily made without the microtome, as the mass is very firm; they 

 should be thin and stained with borax-carmine, and mounted in dam- 

 mar or in glycerin. 



SECTION OF HUMAN SPLEEN, CUT AT RIGHT ANGLES 

 TO AND INCLUDING THE CAPSULE. (Fig. 116.) 



OBSERVE: 



1. The fibrous capsule, (a) Its division into two very distinct 

 portions or layers, (b) The clear translucent appearance of the 

 tissue (elastic) of the outer layer, (c) The darker deep layer with 

 elongate nuclei. (The elastic element of the capsule not infrequently 

 becomes, in the human subject, considerably increased; and this de- 

 velopment occurs irregularly, sometimes in the form of minute 

 nodules. I do not know that they present any pathological signifi- 

 cance. ) 



2. The trabeculae. (The depth to which they may be traced will 

 depend largely upon the direction of the section.) (a) That these 

 are not bands, but bundles, more or less circular, in transverse sec- 



