ABSORPTION. 1 .").") 



to the movements of respiration and circulation; so that serous sacs 

 may be regarded in a certain sense as large lymph-cavities. Fluids 

 placed within these cavities readily find their way into the lymphatics. 

 The cavities referred to are those of the peritoneum, pleura, peri- 

 cardium, aqueous chamber of the eye, and labyrinth of the ear. 



6. In the mucous membrane of the nose, larynx, trachea, and 

 bronchi there have been noticed open pores which are in communica- 1 

 tion with the lymphatics. 



Fig. 43. Section of Dog's Intestine, allowing Villi. (CADIAT. ) 



C, Blood-vessels, injected. d, Lacteals, injected. Blind end of villi en- 

 veloped in a capillary network of blood-vessels. 



Lymphatic vessels of moderate size are supplied with nutrient 

 vessels (vasa vasorum), which are distributed to the external and 

 middle coats of their walls; up to the present time no nerve-supply 

 has as yet been ascertained except for the thoracic duct. 



Eanvier and others state that there is no origin of lymphatics 

 from open spaces in the tissues. They believe lymphatic capillaries 

 are terminated by absolutely closed cuts de sac. 



