ABSORPTION. 



Lymphatic vessels are distributed in nearly all parts of the body. 

 Their existence, however, has not yet been determined in the placenta, 

 the umbilical cord, the membranes of the ovum, or in any of the so-called 

 non-vascular parts, as the nails, cuticle, hair, and the like. 



Origin of Lymph Capillaries. The lymphatic capillaries commence 

 most commonly either (a) in closely-meshed networks, or (#) in irregu- 

 lar lacunar spaces between the various structures of which the different 



Lymphatics of head and I Vfltgil ! Lymphatics of head and 



neck, right. KraMM WfwKwl neck ' left - 



Right internal jugular vein, j ^^SHIi^M^^^g 8 Thoracic duct - 



Right subclavian vein. 1 Left subclavian vein 



Lymphatics of right arm. 



Thoracic duct. 



Receptaculum chyli. 



^^^^^B&jftflBggnggLiiuaiHi 



Lacteals. 



BUS of Iower ex - 



'WMMKBHPIKw'*K*BMi^**54iIiaB^^^^^B 



FIG. 214. Diagram of the principal groups of Lymphatic vessels (from Quain). 



organs are composed. Such irregular spaces, forming what is now 

 termed the lymph-canalicular system, have been shown to exist in many 

 tissues. In serous membranes, such as the omentum and mesentery, 

 they occur as a connected system of very irregular branched spaces 

 partly occupied by connective-tissue corpuscles, and both in these and 

 in many other tissues are found to communicate freely with regular 

 lymphatic vessels. In many cases, though they are formed mostly by 

 the chinks and crannies between the blood-vessels, secreting ducts, and 

 other parts which may happen to form the framework of the organ in 

 which they exist, they are lined by a distinct layer of endothelium. 



