THE LYMPHATICS 183 



which supports the gland tissue proper. The gland possesses a fibrous 

 capsule from which a number of trabeculas pass inwardly through the 

 outer or cortical portion of the gland. The trabeculae then spHt up, 

 and reunite in such a manner as to form a fibrous network, the finer 

 continuations of the trabecular forming a most intricate and dehcate 

 framework in the interior of the gland. In the meshes of this network 

 we find an enormous number of lymphoid cells. This part is the 

 medulla of the gland. 



For the greater part the medulla is separated from the surface of the 

 gland by a considerable thickness of cortex, but at one part of the gland 

 there is an indentation in its surface, and here the medulla approaches 

 quite close to the surface of the gland. The indentation is called the 

 hilum, and here the efferent vessels leave which carry lymph from the 

 gland. Through the gland the lymph passes in what is known as the 

 lymph channel, and this is crossed by the fine prolongations of the 

 trabecule mentioned above, and also by large branched and nucleated 

 cells which are frequently pigmented, so that the lymph tract is frequently 

 easily distinguished from the remainder of the gland by the fact that it 

 is darker in colour. 



The afferent vessels which bring the lymph to the gland are usually 

 more numerous and smaller than the efferent. They enter the gland on 

 its convex surface opposite the hilum. The lymph then takes a course 

 slowly through the lymph tracts in the gland, and leaves the gland by the 

 efferent vessels. Owing to the slow progress of the lymph through 

 them, the glands act as a kind of intercepting trap by arresting the 

 progress of septic material. 



Septic infection spreads quickly up the fore limb, the metacarpal 

 region swelling rapidly as stated ; and this is followed by a similarly 

 rapid swelling of the forearm, particularly on the anterior and inner 

 aspects and along the course of the big subcutaneous veins. This 

 rapidity of the spread of infection is due to the fact that there are no 

 lymphatic glands below the elbow in the fore limb. At the inner aspect 



