176 PRACTICAL MICROSCOPY. 



a very distinct differentiation. At this point, examine every part of 

 the specimen, and endeavor to detect even the most minute collection 

 of this tissue.) (a) Around arteries, constituting the so-called Mal- 

 pighian bodies, (b) Transverse sections of Malpighian bod- 

 ies, noting that the vessel is seldom in the centre of the nodule. 

 (c) Nearly longitudinal sections of Malpighian nodules, observ- 

 ing that the adenoid tissue usually follows or surrounds the artery 

 for a short distance only, (d) That the distribution is not confined 

 to the arteries, but is quite common around trabeculae and beneath 

 the capsule. 



5. The Spleen-pulp. (This will be found in those portions of the- 

 section not occupied by structures previously demonstrated; and will 

 be determined by its light color. Keview the whole area, and en- 

 deavor to differentiate every portion of the adenoid and pulp tissue.. 

 The staining will have been your principal guide thus far, the pulp- 

 elements appearing in strong contrast by their pink eosin color.) 



(H.) 



6. The structural elements of the capsule, (a) The nu- 

 merous minute lymph-spaces and the imperfect vascular sup- 

 ply, (b) The nuclei of the peritoneal cell covering. (This pre- 

 supposes that the section has been selected so as to include the peri- 

 toneal investment.) (c) The abundant and closely packed elastic 

 fibrillae. (d) The muscle nuclei of the deeper parts, (e) Cells 

 containing granular yellow pigment. (The quantity varies largely 

 with different specimens.) 



7. The Malpighian nodules, (a) The arterioles very small 

 and apt to escape attention unless filled with blood corpuscles. (#} 

 The adenoid reticulum. (This will be difficult of satisfactory 

 demonstration, excepting the section be thin.) 



8. The elements of the pulp, (a) Large flattened cells, the- 

 branches forming the mesh work of venous channels. (These are 

 only susceptible of very satisfactory demonstration in the spleen of 

 leucocythcemia.) (b) Red blood-corpuscles. Very numerous and 

 often broken and distorted, (c) Blood pigment, (d) Lymphoid 

 or white blood-corpuscles. 



