1891.] On the Fossa Patellaris of the Corpus Vitreum. 137 



III. " On a Membrane lining the Fossa Patellaris of the Corpus 

 Vitreum." By T. P. ANDERSON STUART, M.D., Professor of 

 Physiology in the University of Sydney, N.S.W. Com- 

 municated by Professor S CHAFER, F.R.S. Received 

 January 12, 1891. 



The 9th edition of Quain's ' Anatomy,' 1882, after giving a de- 

 scription of the hyaloid membrane and its connexions, says, 

 " According to the account usually given, the hyaloid membrane 

 divides in front into two layers : an anterior, continued forwards as 

 the zonule of Zinn, and a posterior, passing behind the lens, the canal 

 of Petit being contained between them. The above description is 

 based upon a renewed original investigation into the relations of the 

 structures which support the lens, and is confirmatory of the state- 

 ments of Meckel, Henle, Brailey, and others, and opposed to those of 

 Iwanoff." Now the description adopted by Qnain discards the poste- 

 rior layer passing behind the lens. The vitreous humour, accord ir g 

 to it, lies immediately against the posterior layer of the lens capsule, 

 and at the canal of Petit may, perhaps, in part occupy the interstices 

 of the suspensory fibres, which are said to pass from the zonula to the 

 periphery of the lens capsule. Thus the whole anterior surface of 

 the vitreous is bare, that is, is not invested by any membrane. 



I cannot agree with this view, for, in the eye of the ox, I have 

 demonstrated to the satisfaction of large numbers of my students and 

 many members of the medical profession in Sydney, and at the Inter- 

 colonial Medical Congress in Melbourne, 1889, that there is un- 

 doubtedly a membrane in this situation. I have found it likewise in 

 the eye of the sheep, goat, dog, and porpoise, so that I entertain no 

 doubt of its general occurrence, notwithstanding that Schwalbe, in 

 1887 (' Anatomic der Sinnesorgane '), adheres to the view of the 

 non-existence of the membrane. This view was more explicitly set 

 forth by Schwalbe in the anatomical part of De Wecker and Landolt's 

 'Traite complet d'Ophthalmologie ' (Paris, 1886). Here, at p. 519, 

 vol. 11, he says what I translate as follows : 



" In the region of the ora serrata the hyaloid begins to gradually 

 thicken and to change its structure, becoming the zonula ciliaris. 

 From this point it constitutes the anterior wall of the canal of Petit ; 

 the posterior wall is identical with the anterior surface of the jelly of 

 the vitreous body, which is differentiated from the liquid contents of 

 the canal of Petit merely by its more dense surface. A cleavage of 

 the zonula, near the ora serrata, into an outer leaflet representing the 

 fibres of the zonula and an inner one lining the fossa patellaris does 

 not take place. Consequently the canal of Petit is to be compared to 

 the other clefts in the jelly of the vitreous body. This description 



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