ENTOZOA IN THE EYE. 215 



which live in serous cavities or in the areolar tissue 

 of other parts of the body. Those which have been 

 hitherto observed in the organs of vision in the 

 human subject are — the Hydatid and the Cysticercus 

 telcB cellulosce, from amongst the class of cestoid 

 worms ; the Monostomum lentis, and Distomum 

 ophthalmohium, belonging to the trematoda ; and the 

 Filaria lentis, and another species of Filaria, belong- 

 ing to the nematoid class of entozoa. 



With the exception of the cysticercus, all of these 

 species have only been observed in a very small 

 number of cases. The filaria lentis, the mono- 

 stomum, and the distomum were found in the crys- 

 talline lens of patients suffering from cataract ; the 

 other filaria which was seen by Quadri, occurred in 

 the anterior chamber of the eye ; the hydatids were 

 seen both in the anterior chamber, and in the deep- 

 seated parts of the eye ;^ the cysticerci have been 

 met with in. most parts of the eye, with the exception 

 of the lens. 



The cysticerci have been more frequently observed 

 in the deep-seated than in other parts of the eye, and, 

 according to Graefe, who has recorded upwards of a 

 dozen cases, they usually occupy the vitreous humour, 

 the choroid membrane, or the retina. Their develop- 

 ment is not generally attended with pain, although 

 some patients have experienced a sense of pressure 



* It has been suggested that the cases of hydatids stated by 

 the earlier writers to have been observed in the anterior chamber 

 of the eye were more probably cases of displacement of the lens, 

 owing to rupture of its capsule. These cases are very doubtful, 

 as the nature of the substance seen in the eye was not properly 

 determined in any of them. 



