310 THE LYMPHATIC SYSTEM, BY F. v. KECKLINGHAUSEN. 



Oedmansson, His, and others have described foramina present- 

 ing features analogous to such stomata. 



We come now to the essential point of the whole inquiry, 

 the nature, namely, of the relation borne by the lymphatics 

 to the surrounding tissues. And we must first ask whether 

 definite channels exist by which the fluids transuded from 

 the blood are conducted to the commencement of the lympha- 

 tics, or whether the surrounding tissues behave like Descemet's 

 membrane, in which pores and canals are present of sufficient 

 magnitude to enable them to be readily seen by means of the 

 microscope ? If we consider the phenomena of the absorp- 

 tion of fat, it appears absolutely requisite to assume, not 

 only that there are foramina in the walls of the capillary lym- 

 phatics, but that there are channels in the surrounding 

 substance of the parenchyma in the case of the villi, though 

 in regard to the other rootlets of the lymphatic vessels, their 

 existence appears less requisite, since their contents, apart 

 from the lymph corpuscles which are probably formed in their 

 interior, ordinarily consist of a fluid destitute of any undis- 

 solved particles, or oil drops. In the parenchyma of the villi, a 

 plexiform disposition of the chyle constituents has been observed 

 to be situated immediately beneath the epithelium, forcibly 

 suggesting that special arrangements are here present, by means 

 of which the vessels containing the chyle are brought into 

 direct communication with the cavity of the intestine. Very 

 recently it has been maintained by Letzerich that a special 

 system of canals, commencing with cup-shaped organs, in 

 the epithelium, conducts the chyle into the central lacteal; 

 but, even in the event of this statement proving correct, there 

 must still be apertures or canals analogous to those above 

 described, which lead from the abdominal cavity to the lym- 

 phatic vessels of the central tendon of the diaphragm. 



A lively discussion is still maintained, as to whether the lym- 

 phatics are closed channels, or whether they stand in communi- 

 cation with interspaces of the tissue, from which, indeed, they 

 may be supposed to be developed. The former view has be- 

 come more definite since Virchow and Donders advanced their 

 doctrines respecting the stellate connective tissue corpuscles ; 

 the corpuscles, in consequence of the fusion of their membranes, 



