168 



ABSORPTION". 



throughout the body. The walls of these vessels are thinner and 

 more transparent than those of the arteries and veins, and they are 

 consequently less easily detected by ordinary dissection. They 



originate in the tissues of the 

 above-mentioned parts by an 

 irregular plexus. They pass 

 from the extremities toward 

 the trunk, converging and 

 uniting with each other like the 

 veins, their principal branches 

 taking usually the same di- 

 rection with the nerves and 

 bloodvessels, and passing, at 

 various points in their course, 

 through certain glandular bo- 

 dies, the " lymphatic" or "ab- 

 sorbent" glands. The lym- 

 phatic glands, among which 

 are included the mesenteries 

 glands, consist of an external 

 layer of fibrous tissue and a 

 contained pulp or parenchy- 

 ma. The investing layer of 

 fibrous tissue sends off thin 

 septa or laminae from its in- 

 ternal surface, which pene- 

 trate the substance of the gland 

 in every direction and unite 

 with each other at various 

 points. In this way theyihrjn 



an interlacing laminated framework, which divides the substance 

 of the gland into numerous rounded spaces or alveoli. These alveoli 

 are not completely isolated, but communicate with each other by 

 narrow openings, where the intervening septa are incomplete. These 

 cavities are filled with a soft, reddish pulp, which is penetrated, 

 according to Kolliker, like the solitary and agminated glands of the 

 intestine, by a fine network of capillary bloodvessels. The solitary 

 and agminated glands of the intestine are, therefore, closely analo- 

 gous in their structure to the lymphatics. The former are to be 

 regarded as simple, the latter as compound vascular glands. 



The arrangement of the lymphatic vessels in the interior of the 



" --a- 



LACTEAI.S, THORACIC DUCT, &c. a. Intes- 

 tine, b. Vena cava inferior. c, c. Right and left 

 subclavian veins, d. Point of opening of thoracic 

 duct into left subclavian. 



