510 



THE TISSUES. 



Fig. 340. 



tissue. (Fig. 340.) The outer coat is composed of areolar tissue 

 and longitudinal fasciculi of smooth muscular fibres. 



The valves of the duct, and of the lym- 

 phatics generally, correspond with those 

 of the veins. The vessels present the same 

 conditions in the duct, as those of the 

 veins. No nerves have yet been found in 

 the lymphatics. 



The lymphatic glands present a thin, fine 

 sheath of areolar tissue inclosing a soft 

 whitish-red parenchyma, in which a fi- 

 brous portion, a soft pulp, and bloodves- 

 sels are seen. 1. The fibrous portion is 

 areolar tissue proceeding from the sheath, 

 and taking the form of many lamellae ; it 

 constitutes an elegant areolated structure 



Transverse section of the hu- 

 man thoracic duct. a. Epithe- 

 lium, striped lamellae, and elastic 

 inner membrane. 6. Longitudi- 

 nal connective-tissue of the tunica 

 media, c. Transverse muscles of 

 the same tunic, d. Tunica adven- 

 titia, with e, the longitudinal mus- 

 cles. Magnified 30 diameters. 

 (milker.) 



Fig. 341. 



1) 



A. One of the inguinal lymphatic glands injected with meran-y ; a, afferent lymphatic vessels 

 from the lower extremity ; b, efferent vessel others arc also seen. B. One of the superficial lym- 

 phatic trunks of the thigh, c. One of the femoral lymphatic trunks laid open longitudinally to 

 display the valves within it ; c, sinus between the valves and the wall of the vessel, d. Surface 

 of one valve directed towards the opposite ; e, semicircular attached margin of the valve. D. Sec- 

 tion of lymphatic gland, showing a a, the fibrous tissue which forms its exterior ; b b, superficial 

 vasa afferentia ; c c, larger alveoli near the surface ; d d, smaller alveoli of the interior ; e e, fibrous 

 walls of the alveoli. (After Mascagrti.) 





