CANAL OF PETIT. 



439 



anterior part of the capsule, in which the lens is contained. It 

 is supposed, by some anatomists, that this membrane is con- 

 tinued completely over the crystalline lens ; but it has not been- 

 separated from it. 



As this lamen extends round the crystalline lens, it is in con- 

 tact with the ciliary processes ; or, with a production from the 

 retina, which is suppossd by some anatomists to pass between 

 them. It is impressed with radiated plates by the ciliary pro- 

 cesses, and some of the pigmentum nigrum of these processes 

 adheres to it. 



As these lamina of the tunica hyaloidea are separated by the 

 crystalline lens, there is a vacuity between them, around the 

 margin of the lens, and this vacuity must necessarily be circu- 

 lar in its course. 



It is not probable that any considerable quantity of fluid is 

 contained in this vacuity ; for the two lamina concerned in its 

 formation, appear in contact with each other. It can be 

 readily demonstrated by puncturing the external lamen, and 

 blowing into it through a small pipe. When thus distended, 

 there appear to be incomplete partitions in the canal, or partial 

 adhesions of the lamina forming it, which have the effect of par- 

 titions ; these partitions are placed in a radiated direction, at 

 some distance from each other, and give the canal a peculiar 

 indented appearance. It is called by the name of the celebrated 

 Petit who discovered it. 



The anterior lamen of the tu- 

 nica hyaloidea, which forms part 

 of this canal, seems to adhere to 

 the coats of the ciliary processes ; 

 for, if a section is made behind 

 the ciliary ligament of all the 

 coats of the eye, the vitreous 

 humor will be found adhering 

 to the anterior portion of the 

 section, when it is lifted up. 



— Fig. 195, is an enlarged 



representation of the canal of 



Petit (called godronne, from its resemblance to the puckers or 



ornaments of silver plate.) It is here shown inflated with air, 



