t 



[ ^27 ] . 



I HAVE faid, CONTRARY TO ALL ANATOMISTS, that the infidc 

 of the iris adheres clofely to the anterior ptrt of the vitreous 

 humour, except where it opens for the lodgment of the cryftal- 

 line; and the better to comprehend this fad, I fliall give a new 

 defcription of the iris. V/ith other anatomifts, I always imagined 

 that this laft was a real continuation of the. choroi'des ; I am 

 now fatisfied that it is not, and that the afTertion is very nearly 

 as abfurd as to affirm that the diaphragm is a continuation of 

 the pleura, though the choroi'des adheres pretty clofely to the 

 fclerotica, near the infertion of the optic nerve ; yet from thence 

 to the ligamentum ciliare, the correfpondence is moftly kept up 

 by blood-veflels and nerves paffing from one to the other. 

 Here a clofe adhefion of the choroi'des to the fclerotica com- 

 mences. At the middle of the fuperior and inferior parts of 

 the eye, it begins at the very edge of the fclerotica, bordering . 

 on the cornea tranfparens, but from thence to the two can- 

 thufes it gradually retires back on the fclerotica ; the adhering 

 part from the choro'ides, called ligamentum ciliare, is truly ten- 

 dinous, and forms an expanfion or covering to the iris ; within 

 fide this are groupes of blood veffels from the arterial circle 

 of the iris, proceeding in nearly ftraight lines, as well to the 

 pupilla as to the ciliary ligament. To prove that the iris is 

 totally different from the choro'ides and truly mufcular, it is 

 only neceffary to obferve that the infide of the ligamentum 

 ciliare anfwering to its breadth, is flefhy and thicker than 

 any other part of this body ; its fibres proceed radiated or 

 nearly fo from thence towards the iris. Here the covering of 

 the anterior part of the vitreous membrane commences, and fo 



clofely 



