284 Account of a Filaria in a Horse^s Eye. 



M. De Blainville, in the Dictionnaire des Sciences Naturelles, 

 describes twelve species of Filaria^ and mentions thirty-one oth- 

 ers, which are doubtful, and whose names are derived from the 

 species of birds, fishes, quadrupeds, insects and reptiles which 

 they inhabit. The points of difference among these do not ap- 

 pear sufficient to constitute them into distinct species, with the 

 exception, perhaps, of the four following, viz. corotiata, acmnin- 

 ata, plicata and alala, which have been minutely described by 

 Rudolphi and De Blainville. For our knowledge of the others, 

 we are chiefly indebted to Lamarck and Rcsssel. The principal 

 animals in which the Filaria has been detected are the vulture, 

 eagle, falcon, owl, swan, duck, stork, heron, lark, starling and 

 limiet, among birds, and the horse, swine, ox, hare, weasel and 

 lion, among quadrupeds ; in numerous species of fishes, and cole- 

 opterous insects, among the lower orders. 



Dr. Nordmann, in his work above referred to, states that he has 

 detected the Filaria in the eye of a person affected with cataract, 

 also a hydatid in the eye of a young woman. Ehrenberg agrees 

 with Nordmann in opinion that cataract and some other diseases 

 of the eye, are probably owing to an accumulation of these par- 

 asitic animals. This writer has shown very satisfactorily that 

 quadrupeds, birds, reptiles and fishes have each their eye-worms, 

 which are, for the most part, peculiar to each species. Several of 

 these are figured in his work ; among which, one that infests the 

 eyes of different species of perch, is very conspicuous. In one 

 instance he counted 360 of these in the eye of a single fish af- 

 fected with cataract. " This little animal," says Kirby in his 

 Bridgewater Treatise, "appears something related to the Planaria 

 or pseudo-leech, and from Dr. Nordmann's figures seems able, like 

 it, to change its form. Underneath the body, at the anterior ex- 

 tremity, is the mouth, and in the middle are what he denomin- 

 ates two sucking-cups ; these are prominent, 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 ascertairi that it was used 

 for prehension." 



It is remarkable that these animals, small as they are, are in- 

 fested with parasites of their own. These appear like minute 

 brown dots or capsules, attached to the intestinal canal. When 

 extracted and laid upon a smooth surface, these capsules burst, 



