ORIGIN OF LYMPHATICS. clxxxiii 



produced by the short distended branches of a very close lymphatic net- 

 work, and transitions are accordingly met with between this and the more 

 usual and regular forms. 



But whilst the superficial commencement of 



lymphatic* is generally plexiform, the rule is p 1 ^ ^ 



not without exception. The lacteals of the 

 intestinal villi, for example, although they form 

 networks in the larger and broader villi, arise 

 in others by a single vessel beginning with a 

 blind or closed extremity at the free end of 

 the villus, whence it sinks down to join the 

 general plexus of the intestinal membrane. 



Lacunar origin. When lymphatics arise 

 deeply, their origin may be hidden from view, 

 and the precise mode in which it takes place 

 unknown. There may be cases in which it is BREAST INJECTED (after 

 still plexiform ; but another and doubtless more Breschet). 



general mode of origin from the interior of ,, . , , , , 



. , ., , . , a, superficial, and o, deeper 



organs, long suspected and often upheld on pl exus ; c, a lymphatic vessel, 

 imperfect evidence, has now been satisfactorily -which proceeded to the axil- 

 ascertained, which may not inappropriately be I ar 7 glands, 

 termed lacunar. In this case the lymphatic 



vessels proceed from irregular or shapeless spaces in the internal parts 

 of organs ; the spaces, that is, which intervene between the several struc- 

 tures of which the organ is composed. Thus, in a gland, they are the 

 spaces which lie between or surround the blood-vessels, secreting tubes or 

 saccules, partitioning or inclosing membranes, and the like. Though shape- 

 less, or at least of no regular form, these anfractuous cavities are limited 

 and defined by a lining of epithelium, agreeing in character with that of 

 the lymphatic vessels. It may be presumed that their opposite sides are 

 in apposition or in near proximity, as in serous membranes, for the lymph 

 deposited in these recesses is not suffered to accumulate, but is drained off 

 by the lymphatic vessels which lead out of them. 



The lacunar condition of the lymphatic system at its commencement was shown 

 to exist in the testicle by Ludwig and Tomsa, and has since then been found in the 

 kidney by Ludwig and Zwarykin, in the thymus gland by Frey, in the spleen by 

 Tomsa, in the liver (forming canals which inclose the blood-capillaries) by Mac- 

 Gillivray, and in the salivary glands by Giannuzzi. His has also discovered that 

 the blood-vessels of the brain and spinal cord are surrounded and inclosed by 

 lymph-channels perivascular canals which follow their course and eventually 

 terminate in ordinary lymphatic vessels ; an arrangement that brings to mind an 

 earlier observation of liusconi, who found that the aorta and mesenteric arteries 

 of the frog and salamander are inclosed in large lymphatic canals. The spaces 

 which so extensively separate the frog's skin from the subjacent muscles, were 

 recognised by the late Professor Johannes Muller as belonging to the lymphatic 

 svstem, and von Recklinghausen has shown that the subcutaneous lymph-spaces of 

 the frog's leg communicate with lymphatic vessels which envelope the blood-vessels 

 of the foot ; also that milk injected into these spaces finds its way into the blood. 

 The lymphatic system of man and the higher animals, in being thus partly consti- 

 tuted by lacunee or interstitial receptacles, so far agrees with the sanguiferous system 

 of crustaceans and insects. 



It has been sometimes maintained that the lymphatics of glandular organs com- 

 municate at their origin with the ducts ; but, although it is no uncommon thing for 

 matters artificially injected into the ducts of glands, as, for instance, those of the 

 liver and testicle, to pass into the lymphatics, a careful examination of such cases 



n 2 



