284 



ABSOKPTION LYMPH AND CHYLE. 



culated, from the projections of the follicles just beneath the investing mem- 

 brane. The interior of the glands is soft and pulpy. It presents a coarsely 

 granular, cortical substance, of a reddish- white or gray color, which is one- 

 sixth to one-fourth of an inch (4 to 6 mm.) in thickness in the largest 

 glands. The medullary portion, which comes to the surface at the hilum, is 

 lighter colored and coarser than the cortical substance. Throughout the 

 gland, are found delicate fasciculi of fibrous tissue connected with the in- 

 vesting membrane, which serve as a fibrous skeleton for the gland and divide 

 its substance into little alveoli. The structure is far more delicate in the 

 cortical than in the medullary portion. 



Within the alveoli, are irregularly oval, closed follicles, about ? | u of an 

 inch (100 ft.) in diameter, filled with a fluid and with cells like those con- 

 tained in the solitary glands of the intestines and the patches of Peyer. These 

 follicles do not seem to occupy the medullary portion of the glands, which, 

 according to Kolliker, is composed chiefly of a net- work of lymphatic capil- 

 laries, mixed with rather coarse bands of fibrous tissue. The follicular struct- 

 ures in the lymphatic glands resemble the closed follicles in the mucous mem- 

 brane of the intestinal canal and the Malpighian bodies of the spleen. 



According to Von Kecklinghausen, there exist in the substance of the 

 lymphatic glands great numbers of lymph-spaces or canals, which are proba- 

 bly lined with endothelium; 

 and these spaces communicate 

 with the efferent vessels, by 

 the stomata. The afferent 

 vessels, two to six in number, 

 penetrate the gland, and prob- 

 ably empty their contents into 

 the lymph-spaces. The lymph 

 is then collected from the 

 lymph - spaces, by the vasa 

 efferentia, one to three in 

 number, which are always 

 larger than the afferent ves- 

 sels. 



The lymphatic glands are 

 supplied with blood, some- 

 times by one but generally by 

 several small arteries, which 

 penetrate at the hilum. These 

 vessels pass directly to the 

 medullary portion and there 

 break up into several coarse 

 branches to be distributed to the cortical substance, where they ramify in a 

 delicate, capillary net-work with rather wide meshes, in the closed follicles 

 found in this portion of the gland. This capillary plexus also receives 

 branches from small arterial twigs which penetrate the capsule of the gland 



FIG. 93. Different varieties of lymphatic glands (Sappey). 



