SECTION OF MESENTERIC LYMPHATIC NODE. 169 



PEACTIOAL DEMONSTRATION. 



The mesenteric lymphatic nodes present the most typical structure, 

 may be obtained from the human subject, if fresh, although those 

 from the dog are preferable, on account of the better condition of the 

 tissue as usually secured. 



The nodes should be sliced in half, placed in Miiller for a week, 

 and then hardened by two days' immersion in strong alcohol. 



Sections should be mounted, of two kinds, viz. : Those including 

 the whole area of the node which need not be very thin for demon- 

 stration of the scheme or plan of structure, and excedingly thin ones, 

 even though they may include only a small part of the organ, for 

 study of the details of the adenoid reticulum. The latter purpose 

 will be subserved by shaking a number of thin cuts in a test-tube 

 with alcohol for a few minutes, and with considerable violence, even 

 to the sacrificing of most of the sections. The agitation will dislodge 

 the lymph cells, which otherwise would obscure the histology of the 

 follicular cords. 



Stain deeply with haema. and eosin, and mount the thicker sections 

 in dammar, and those especially thin in glycerin. 



SECTION OF MESENTERIC LYMPHATIC NODE. 



(Figs. 113 and 114.) 

 OBSERVE : 



(L.) 



1. The fibrous capsule. (Note the elongate dots in the deeper 

 parts of the capsule the nuclei of the smooth muscular tissue, 

 the thick-walled arteries, the lymph spaces.) 



2. The trabeculae. (Trace these as they penetrate the organ and 

 observe that they frequently end abruptly, on account of having 

 curved, so as to leave the plane occupied by the section. The tra- 

 beculse are not partitions, like the iuterlobular pulmonary septa or 

 the prolongations from the capsule cf Glisson in the liver; they are 

 not unlike rods or posts, making a framework and not producing 

 alveoli. Find one divided transversely.) 



3. The follicular cords. (They are recognized as granular masses 

 between the trabeculae. Observe the varying forms, largest and 

 more spherical or ellipsoidal, near the periphery cortex. The 

 smaller ones of the central region (medulla) must not be overlooked, 

 as the differentiation is sufficiently marked between them and the 

 variously sectioned trabeculae.) 



4. The lymph paths. (These can be appreciated by remembering 



