

E. THE SMALL INTESTINE, BY E. VERSON. 567 



by agitation of the preparation in a test-tube half filled with 

 water, a network or plexus of fibres comes into view, similar 

 to, though somewhat closer than that presented generally by 

 the mucous membrane of the small intestine. The follicles 

 consequently are composed of a plexus of fibres and of cells 

 (lymph corpuscles) which fill the interspaces between them. 

 But, just as the plexus of the mucous membrane presents his- 

 tological differences under various circumstances, so may the 

 framework of intestinal follicles differ, sometimes appearing as 

 a tissue of anastomosing cells, the nuclei of which coincide 

 with the thickened nodal points (child, rabbit), sometimes as a 

 plexus of rigid hyaline trabeculae (adult man, cat), and some- 

 times as a fibrous network (young dog). 



The framework, whatever may be its form, is directly con- 

 tinuous laterally and above the muscularis mucosse with the reti- 

 cular tissue of the mucous membrane. In the deeper parts, on 

 the other hand, the meshes gradually become more compact, 

 and either, covered with epithelium, form the boundary of the 

 so-called lymph sinuses, or, where these are deficient, are 

 applied to the dense submucous tissue which constitutes the 

 cord-like septa between the follicles, and extend to near the 

 muscularis mucosse. But in the event of the septa not 

 reaching so high, the follicles just below the muscularis 

 mucosse may for a short distance be continuous with each 

 other. 



Regarded from another point of view, however, the frame- 

 work is in direct connection with the vessels of the follicle, and, 

 indeed, not only with the larger ones by means of their tunica 

 adventitia, but also with the most delicate capillaries. This is 

 effected by means of a fibrous network, and in well-prepared 

 specimens the capillaries may be frequently observed to give 

 off processes that suddenly become attenuated into fibres, 

 which coalesce with those of the general mass. 



As in man, so in the greater number of animals, the follicles reach 

 the surface of the mucous membrane, and elevate this in the form of a 

 cap (rabbit, sheep, calf, pig). It occurs, occasionally, however, that 

 the follicles do not reach the surface of the mucous membrane, be- 

 coming continuous at some distance from it with the ordinary adenoid 

 tissue of the membrane (cat). 



