22 Henry B. Ward 



before the Buffalo meeting of the American Academy of Oph- 

 thahnology and Oto-laryngology. 



CASES WRONGLY ASSIGNED TO F, LOA 



It is no matter of conjecture that other species of filaria than 

 F. loa do occur in the human eye. In Italy, for example, Ad- 

 dario (1885) observed in the eye of man a nematode which he 

 named F. coiijiiiictk'ac. Later Grassi (1887) published an ex- 

 tended description of the same form to which he gave the name 

 of F. iiicnnis. He also discussed the cases of its occurrence in 

 man and showed it to be a normal parasite of the horse and ass 

 that, as an erratic parasite, occurs at times in the human eye. 

 In spite of a certain similarity in general character its differ- 

 entiation from F. loa is not a matter of any difiticulty in case a 

 precise examination is made of the specimen in question. How- 

 ever, when no such examination is recorded, the area of geo- 

 graphical distribution becomes determinative in general, and 

 cases with insufficient data occurring within the range of this 

 or a similar species will be referred to it by preference rather 

 than to F. loa.^ Thus the cases from Italy, in so far as they are 

 not errors in observation, are naturally assigned to F. conjunc- 

 tivae in the absence of more precise information as to the actual 

 species concerned. 



In similar fashion the case of Drake (1894) from Madras, 

 India, is regarded by Blanchard as belonging most probably to 

 F. equina, a common parasite of the horse and ass in that region 

 and known in such hosts to make occasional incursions into the 

 eye. The case of Neve (1895), also from India, in which the 

 parasite was designated specifically as F. Joa, appears to me to 

 be u-'idoubtedly an error in determination and to concern rather 

 the species F. equina. I was unable to consult a copy of the 

 paper by Macnamara (1863) which, to judge from the title, 

 refers to cases also to be assigned to the species F. equina 



' Recinrocally, it is just to assign to /^. /<;<? sucli cases as that of Maurel 

 (Trucy, 1873) since the par.^site was removed at Gaboon where the Loa is 

 common, while it is beyond the range of the Guinea worm, to which the 

 case is referred bv the author. 



292 



