THE EYE. 



421 



and nucleated (Iwanoff and Vircliow); according to tlie former 

 observer the cells have contractile powers. 



The hyaloid membrane is described as structureless by Schwalbe, 

 as fibrous by Pappenheim^ Bowman, and Fuikbeiner. 



The vessels o£ the vitreous body (Fig*. 260) are as follows. The 

 A. Iiyaloldea arises at the lowest point of the corpus ciliare ; it almost 

 immediately divides into two branches, which form a ring" at a 

 distance of about 0*5 mm. from the lens and lying- on the surface 

 of the vitreous body (Fig*. 260 I, II). One, It. nasaJis, passes to 

 the nasal side and courses through one-fourth of the circle; the 



Fig. 260. 



The vessels of the vitreous body ; after Hans Virchow. 



I. Vessels of the vitreous body ; seen from the deeper pole and slightly from ab<jve. Magnified 

 6 times. 

 II. Arteries of the vitreous body of the right eye. 

 A Seen from the proximal pole. 

 B Seen from the nasal side. 

 III. Veins of the vitreous body of the left eye. 

 A Seen from the proximal pole. 

 B Seen from the nasal side. 



a Nasal vein. 



b Temporal vein. 



c Branch (constant) of temporal vein. 



n R. nasalis of the ophthalmic artery. 



t R. temporalis of the ophthalmic artery. 



t' Termination of the R. temporalis. 



V Ventral vein. 



other, R. temporalis, courses through three-fourths of the circle. The 

 branches are all given off proximally and at right angles to the circle 

 (Fig. 260 I, II). From the R. nasalis only one branch arises, from 

 the R. temporalis seven, the first of which corresponds in point of 

 origin with the branch from the R. nasalis. The branches on the 

 nasal and temporal surfaces of the vitreous body arc the shortest. 



