330 THE BLOODVESSELS OF THE EYE, BY TH. LEBER. 



them was long ago pointed out by Briicke * and Rouget, f and 

 more recently by Iwanoff and Rollett. J 



An analogous structure to the peculiar trabecular tissue 

 which fills the canal of Fontana, occurs, according to these 

 observers, in Man also, though in small amount ; this is the so- 

 called ligamentum pectinatum, that extends from the border of 

 the membrane of Descemet over the circulus venosus, towards 

 the insertion of the ciliary muscle and the origin of the iris. 



The circulus venosus may be injected both from the 

 ophthalmic artery and vein, though not readily, without extra- 

 vasation^ Owing to such extravasations the plexiform struc- 

 ture of the venous circle is more or less concealed, but the 

 extravasations are recognized easily by their having no sharply 

 defined contour. Extravasations are produced still more readily 

 by direct injection through simple penetration with the point 

 of the canula, for which purpose mercury was formerly em- 

 ployed. I have recently found, however, that Prussian blue 

 and glycerine can be thus injected with great facility, and, in 

 part at least, without extravasation, into the vascular circle, 

 and that the fluid penetrates by this means at a low pressure 

 into the finest branches of the episcleral veins, and into those 

 of the ciliary muscle. 



These experiments with injection fluids, the presence of 

 blood in the dead body, especially in those who have been 

 hanged (Schlemm), and the demonstration of a thin vascular 

 wall which may be made with facility in transverse sections, 

 may be collectively regarded as finally proving the blood- 

 vascular nature (still doubted by many) of the circulus 

 venosus. || 



called Canal of Fontaiia or of Schlemm), in the Archiv fur Ophthalmology, 

 Band xiii., Heft ii. , p. 425, et seq. 



* Anatomiscfie Beschreibung d. menschlichen Augapfels, pp. 52 and 53. 



+ Loc. cit., p. 117. 



J Iwanoff and Rollett, Bemerkungen zur Anatomic der Irisanheftung 

 (Remarks on the anatomy of the attachment of the Iris, etc.), Archiv fur 

 Ophthalmologie, Band xv., Heft i., p. 23, et seq. 



Though Pelechin was not able to effect this, I may adduce my own 

 experience in opposition ; for I found, when the injections were otherwise 

 successful, the vessels of the circulus venosus were, as a rule, filled. 



|| The essay of Schwalbe on the Lymphatics of the Eye and their limits, 



