336 THE LYMPHATICS OF THE EYE, BY G. SCHWALBE. 



composed of numerous very flat lamellae, the basis of which is 

 formed of a rich plexus of elastic fibres. Closely connected 

 with this plexiform tissue are numerous very flat and more or 

 less branched pigment cells, which, when numerous, lie in close 

 apposition, and resemble an epithelium. In many animals, as 

 for example, in the Pig, in addition to these pigment cells, 

 small flat colourless cells are constantly found to be pre- 

 sent on both sides of the elastic lamella thus formed, or where 

 this is firmly attached to the tissue of the sclerotic, on 

 one side only, is a very thin glass-clear membrane, present- 

 ing at certain points ellipsoidal nuclei projecting beyond the 

 general plane of the lamella. If these membranes are treated 

 with solutions of nitrate of silver, containing from one-fourth 

 to one per cent, of the salt, a beautiful plexus of dark sil- 

 vered lines is brought into view, each mesh of which corre- 

 sponds to one of the ellipsoidal nuclei. The elastic lamella of 

 the supra-choroidea is then, it appears, covered by an endo- 

 thelium, which differs but little from that of the lymphatic 

 canals. Its presence may be demonstrated both on the outer 

 surface of the choroid and upon the inner surface of the scle- 

 rotic, covering uniformly the whole perichoroidal system of 

 cavities. 



If injections be forced into the perichoroidal space, it will be 

 found that the fluid passes into the second of the above- 

 mentioned lacuniform lymphatic spaces at four points which 

 lie close behind the points of emergence of the vense vorticosse. 

 A careful examination of this region shows that the lymphatic 

 vessel at first invests the vein as it passes obliquely through 

 the sclerotic like a sheath (fig. 370), but shortly before reach- 

 ing the external surface it separates from it, and lies on the 

 inner and inferior side of the vessel. Its passage through 

 the sclerotic is thus for the most part perivascular. Having 

 reached the surface of the bulb, the injected fluid passes into a 

 lymphatic cavity which exists between the sclerotic and the 

 fascia .of Tenon, and may be termed Tenon's space or cavity 

 (fig. 369, Q. 



This is lined throughout by an endothelial layer of cells 

 resembling that which lines the perichoroidal space. A net- 

 work of dark silvered lines may easily be shown to exist- on 



