io6 



TENTH LECTURE. 



diffused throughout the human body, is permeated by- 

 millions of clefts and spaces. They receive nutritious plas- 

 matic or lymphatic fluids, and contain wandering lymphoid 

 cells. In the serous cavities and sacs we meet with an im- 

 mense lymphatic lacunar system ; nevertheless, the quantity 

 of fluid is small. 



Now, do these latter lymphatic passages, lined with endothe- 

 lium, pass over continuously into these connective-tissue canals, 

 and do the former open into the system of serous caverns ? 



It is just these questions which we are now to answer. 

 Let us tarry for an instant at the latter relations. 



A communication of the lym- 

 phatics with the cavity of the 

 serous sac has, for several years, 

 been recognized with certainty. 

 The names of Recklinghausen, 

 Ludwig, Dybkowsky, Schweig- 

 ger-Seidel and Dogiel deserve 

 mention here. 



Recklinghausen discovered at 

 the under surface of the centrum 

 tendineum of the rabbit (Fig. 103, 

 i), between the epithelium, aper- 

 tures (a) of not inconsiderable size, 

 or at least greater than the diame- 

 ter of a red blood corpuscle. He 

 saw how the milk and color gran- 

 ules entered here and reached the 

 lymphatics of the diaphragm. 

 Other short lateral passages of the 

 lymphatics were then found to 

 open into these apertures (2, b). 

 No further doubt can, therefore, 

 exist here. 



The question assumes a different shape, however, concern- 

 ing the relation of the above mentioned connective-tissue 

 chasm to the vascular system. 



Fig. 103. — 1. Epithelium of the under 

 surface of the centrum tendineum of the 

 rabbit ; a, apertures or stomata ; 2. sec- 

 tion through the pleura of the dog ; b, 

 free opening, short, lateral passage of the 

 lymphatic canal ; 3, epithelium of the me- 

 diastinum of the latter animal ; a, pores. 



