S52 THE VITREOUS HUMOUR, BY PROF. A. IVVANOFF. 



the detachment of the vitreous with the zomila from the membrana 

 lirnitans. 



In the year 1814, Martegiani described a funnel-shaped depression 

 in the vitreous at the point of entrance of the optic nerve, which he 

 named the " area." 



This " area Martegiani " is really the commencement of the canal 

 which has been incorrectly designated the canalis hyaloideus Cloqueti. 

 Cloquet never saw and never depicted the canal in adults ; he only 

 describes the course of the capsular artery in the foetal vitreous. 



Hannover describes the canal better, but states expressly that he 

 has never found it open, and thus really knew nothing of the existence 

 of a proper canal. 



The account given by Finkbeiner * is not clear ; of the existence 

 of an open canal in any fully developed eye of Mammal or Man he 

 really says nothing. He describes at length only the eye of the 

 Ox, in which two elongated arese unite to form a solid cord traversing 

 the vitreous. 



The presence of this canal as a patent tube existing throughout life 

 in the eye all Mammals and of Man, and gradually increasing to the 

 period of complete development of the whole eye, was first demon- 

 strated by Stilling, who described the method by means of which it 

 can be demonstrated in the fresh eye. 



The cells of the vitreous are situated only in its external 

 superficial layers ; in the deeper layers we meet only with 

 derivatives from them, that is to say, with nuclei and shrivelled 

 vesicles. Though their form is very various, they can all be 

 classed under three principal groups. 



1. Round cells with large nuclei, the latter surrounded by 

 coarsely granular protoplasm. These occur chiefly in the ante- 

 rior portions of the vitreous, especially in children, in whom 

 they often contain several nuclei. 



2. Fusiform and stellate cells. These are met with through- 

 out the peripherical portions of the vitreous. The stellate cells 

 usually possess long, fine, ramified processes, which are. beset 

 with varicose dilatations. 



3. A very characteristic form of round cells, which contain 

 in their interior a large, round, and perfectly transparent 



* Loc. ctf., p. 332. 



