118 STUDENTS HISTOLOGY 



which branch, broaden, and inosculate to form the supporting 

 framework of the pulp. 



The arteries are frequently surrounded by nodules of lymphoid 

 (or adenoid) tissue, sometimes globular, more frequently consider- 

 ably elongated, and following the vessel for a considerable distance. 

 These nodules are called MalpigJiian bodies. They bear no resem- 

 blance to the similarly named structures in the kidney, excepting, 

 perhaps, when seen in transverse sections by the naked eye. 



The spleen will thus be seen to consist of fibrous trabeculated 

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

 of lymphoid tissue. 



PRACTICAL DEMONSTRATION 



The organ must be perfectly fresh. If human tissue cannot be obtained 

 in good condition, recourse may be had to the ox, which will provide an ex- 

 cellent substitute. The small supernumerary spleens, not infrequently found 

 during post-mortem work, are most desirable, as sections can be easily made 

 through the entire organ. 



Pieces of tissue a centimeter thick, including a portion of the capsule, 

 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 or hsematoxylin, and mounted in balsam. 



SECTION OF HUMAN SPLEEN, CUT AT A RIGHT ANGLE TO AND 

 INCLUDING THE CAPSULE. (Fig. 82) 



OBSERVE : 

 (L.) 



1. The fibrous capsule. The clear, translucent appearance of 

 its elastic tissue and the elongated nuclei of the smooth muscle- 

 cells. (The capsule not infrequently becomes considerably thick- 

 ened in the human subject, and the development occurs irregularly, 

 sometimes in the form of minute nodules.) 



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 trans- 

 verse section. (6) Their irregular course, quickly after leaving 

 the surface, (c) That occasionally a small artery may be found 

 within them, though they are usually destitute of large vessels. 

 (d) The elongated nuclei of the muscular fibers forming part of 

 the trabeculag. 



