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TEXT-BOOK OF PHYSIOLOGY. 



which is strengthened by fibrous tissue derived from the middle 



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Lymph-glands. In their course toward the thoracic duct the 



lymph-vessels pass through a num- 

 ber of small lenticular bodies 

 termed lymph-glands. These are 

 exceedingly abundant in some situ- 

 ations, as the cervical, axillary, and 

 inguinal regions, and the abdominal 

 cavity. As the lymph-vessels_ap- 4 

 proach a gland they,jdivide into a 

 number of branches before entering 

 it, known as the afferent vessels. 

 From the opposite side of the gland 

 the lymphatics again emerge as 

 efferent vessels to unite to form 

 larger trunks. A section of a gland 

 shows that it consists of an outer 

 dense cortical and an inner soft 

 pulpy medullary portion. Each 

 gland is covered externally by a 

 dense membrane of fibrous tissue 

 containing in its meshes non-stri- 

 ated muscle-fibers. From the inner 

 surface of this membrane there pass 

 inward septa of connective tissue 

 which, as they converge toward the 

 center of the gland, divide the outer 

 zone of the gland into small conical 

 compartments or alveoli. When the 

 septa reach the medullary portion, 

 they subdivide and form bands or 

 cords which interlace in every direc- 

 tion and constitute a loose mesh- 

 work the spaces of which communi- 

 cate with one another and with the 

 alveoli (Fig. 90). Within the meshes 

 of this framework the proper gland 

 substance is contained. In the cor- 

 tical compartments it is moulded 

 into pear-shaped masses; in the 

 medullary meshwork it assumes 



the form of rounded cords which are connected with one another. 

 In both regions, however, it is separated from the septa by a space 

 termed a lymph sinus, through which the lymph flows as it passes 



FIG. 



89. LYMPH-VESSELS OF THE 

 A33i.(Deavcr.) 



