104 THE ESSENTIALS OF HISTOLOGY 



(perilymphatic nodule) ; or the lymphatic is dilated into a sinus and 



FIG. 128. DEVELOPING LYMPHATIC NODHLES, FROM THE OMENTUM OF A GUINEA- 

 PIG. 



A, perilymphatic nodule ; a, lymphatic vessel ; c, part of its epithelial wall, seen in optical 

 section ; <?, lymph-corpuscles within the vessel ; b, lymphoid tissue of the nodule ; d, blood- 

 capillaries ; B, endolymphatic nodule ; a, vein ; 6, artery ; c, capillaries ; d, a lymphatic 

 vessel, in which this whole system of blood-vessels is enclosed ; e, lymphoid tissue within 

 the lymphatic vessel ; /, wall of the lymphatic in optical section. 



the formation of lymphoid tissue occurs within it (endolymphatic 

 nodule) (see fig. 128). 



