WORMS IN THE EYES. 
Dr. Nordmann* has given an account of a guinea- worm 
(jilaria medinensis ) which was extracted from the eye of a person 
affected with cataract ; and another of an hydatid from the eye 
of a young woman. 
But besides those that infest our own visual organs, quad- 
rupeds, birds, reptiles, and fishes, have each their eye-worm . 
Dr. Nordmann has discovered a remarkable one in several dif- 
ferent species of perch , sometimes in such numbers as must have 
interfered with that distinct sight of passing objects which ap- 
pears necessary to enable predaceous animals to discover their 
prey in time to dart upon it and secure it. In a single eye he 
has detected in different parts 360 of these animals. When 
much increased in number they produce cataracts in the eyes of 
the fishes which they infest. 
This little animal appears related to the planaria or pseudo 
leech, and to be able, like it, to change its form. Underneath the 
body, at the anterior extremity, is the mouth, and in the middle 
are, what he denominates, two sucking cups. These are pro- 
minent, and, viewed laterally, form a truncated cone. The anterior 
one is the smallest and least prominent, and more properly a 
sucker : the other probably has other functions, since he could 
never ascertain that it was used for prehension. 
A kind of metamorphosis seemed to take place in these ani- 
mals, for our author observed that they appeared under three 
different forms. 
On looking over the author’s list, it appears that five out of 
seven of the eye-worms which he describes are attached to dif- 
ferent species of the perch, and one cannot help feelifhg some 
commiseration for these poor animals ; but when we recollect 
that they form the most numerous body of predaceous fishes in 
our rivers, we may conjecture that these worms are placed where 
we find them in order that the organs of vision in the perch may 
be rendered less acute, and thousands of roach, and dace, and 
carp, and tench, may escape destruction. 
These little pests, small as they are, have a parasite of their 
own to avenge the cause of the perch. Dr. Nordmann observed 
some very minute brown dots or capsules attached to the intes- 
tinal canal : when these were extracted by a minute scalpel, and 
laid upon a piece of talc, the membrane that inclosed them burst, 
and forth issued living animalcules belonging to the genus mo?ias, 
* Micrographische Beitrage. 
