CYST1CEKCUS IN THE EYE. 120 



fingers, go out, &c. ; but at the time when Von Graefe made his 

 report, all dread of chronic chorioiditis was not got rid of. 



d. In the retina. — In one case the patient observed, three 

 weeks before his visiting Graefe's hospital, a cloud in front of the 

 left eye in the middle of the field of vision, and diffusing itself 

 thence towards the sides, so that the patient only had a perfect 

 sensation of light from the sides, whilst in the middle of the axis 

 of vision only large and strongly illuminated objects glimmered 

 as if through a thick cloud. In course of time, however, the 

 sensibility to light was entirely extinguished in this eye. The 

 lens and vitreous humour were clear, but in the middle of the 

 retina a shining greenish body was seen, which was bordered by 

 convex circular margins and lay a little outwards from the centre 

 of the retina on the outside of the optic nerve. The rest of the 

 retina was healthy. Examined in the reversed image, the body 

 appeared as a perfect, roundish, greenish vesicle, four times larger 

 in diameter than the entrance of the optic nerve. It was firmly 

 attached to the retina, and projected with its anterior wall into the 

 vitreous body,in which was perceived awhite,button-like, projecting 

 appendage, distinctly marked by its greater opacity and its colour, 

 which shifted its place, although no separate parts could be per- 

 ceived upon the knob, and over which a pair of vessels ran 

 forwards. On this account Graefe supposed that the worm had a 

 fine enveloping membrane. "When the axis of vision was com- 

 pletely fixed, the walls of the vesicle exhibited fiattenings or cup- 

 like impressions in several places simultaneously, together with 

 movements which diffused themselves in an undulatory manner. 

 In three weeks the vesicle had increased about one third in 

 diameter and reached to the optic nerve. The head had passed 

 from the centre to beneath the upper margin, and appeared to 

 have grown like a small vesicle out of the previous one, that is to 

 say, the enveloping cyst had probably burst, and a small vesicle 

 protruded which sat upon the former. On the head distinct 

 swellings and a neck-region, sometimes extended and sometimes 

 retracted, were now seen. Ten weeks after the first observation, 

 the vesicle was not remarkably enlarged, but less greenish and 

 more transparent. The above-mentioned vessels appeared to 

 be obliterated cords. The small appendage was nearly as large 

 as the original vesicle and covered the optic nerve entirely. The 

 rest of the retina had lost its colour, and was covered with 

 irregular, blended, pale spots, of which Graefe did not know 



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