LYMPHATIC NODES OK GLANDS. 167 



LYMPHATIC NODES OE GLANDS. 



At numerous points along the course of lymphatic vessels they pen- 

 etrate small nodules of so-called adenoid tissue, which have heen 

 termed lymphatic glands. They are frequently microscopic; others, 

 again, not unusually attain the size of a large pea. They secrete 

 nothing, hence are not glands. They are somewhat sponge-like in 

 structure, and the lymph filters slowly through them. 



Most frequently several ducts enter one of these larger nodes, while 

 perhaps only a single efferent will be found. 



The histology of a lymph node is not always easily comprehended 

 by the student, and I have endeavored to make a diagram (Fig. 112) 

 that would simplify the matter somewhat. They are enveloped by a 

 capsule of connective and involuntary muscular tissue, which sends 

 trabeculm into the body of the organ, and these branching posts sup- 

 port the structure as a framework. The interstices are quite small in 

 the more central portion and larger toward the periphery; this has 

 resulted in the application of the terms medullary and cortical to the 

 respective parts. The nutrient blood-vessels are contained in the 

 framework. The compartments contain the structure peculiar to the 

 lymphatic system, viz., adenoid tissue. 



Adenoid tissue consists of a mass of flattened cells, with numerous 

 delicate fibrillar prolongations, which branch and anastomose so as to 

 form an interwoven structure the adenoid reticulum. Klein regards 

 the cells as forming no essential part of the structure, but considers 

 them as flattened plates attached to the fibrils. The meshes of the 

 adenoid reticulum are in connection with the fibres of the trabeculae 

 and, with exception of the portion next the latter, are filled crowded, 

 in fact with countless small spherical lymphoid cells. Those por- 

 tions of the tissue which contain the cells are termed follicular cords. 



The lymph path is the portion between the fibrous trabeculae and 

 the follicular cords. 



When we learn that the trabeculae, follicular cords, and lymph 

 paths each pursue very tortuous and branching routes, we can appre- 

 ciate the complexity of the organ as a whole. 



The blood-vessel arrangement presents no anomalies. The small 

 arterial trunks enter within the trabeculae, finally break into capilla- 

 ries which supply the follicular cords, etc., and the blood is then col- 

 lected by the venules for the efferent veins. 



