1896.] NATURAL SCIENCES OF PHILADELPHIA. 271 



REMARKS ON FILARIA. 

 BY FREDERICK P. HENRY, M. D. 



The case which is the basis of my remarks belongs to one of a 

 group of diseases included under tbe generic term " filariasis," by 

 which is understood an affection caused by one or other species of 

 Filaria. This parasite is by no means rare in the lower animals, 

 especially in the dog, but I will confine my remarks to those Filariie 

 which infest the blood of man. Of these, three species are univer- 

 sally recognized : (1) Filaria sanguinis hominis nocturna, (2) Fil- 

 aria sangxvinis hominis dinrna, (Z) Filaria perstans. This classifica- 

 tion is based upon the habits of the filarial embryos, the first species 

 being found in the superficial vessels solely or chiefly during the 

 night; the second solely or chiefly during the day, while the third 

 is constantly present in the cutaneous capillaries. 



There is a fourth species recently discovered by Dr. Patrick 

 Manson, formerly of Amoy, China, now of Londop, which he has 

 modestly named Filaria Demarquayi, after Demarquay, the dis- 

 coverer of Filaria nocturna. 



Filaria diurna and Filaria perstans are confined thus far to the 

 West of Africa and adjoining districts, while the Filaria nocturna is 

 widely prevalent in the tropics and endemic in certain sections of the 

 United States. The adults of Filaria nocturna have been frequently 

 found ; that of Filaria perstans never, so far as I have been able to 

 ascertain. In the opinion of Manson the Filaria loa of the eye of 

 the negro of Old Calabar is probably the adult form of the Filaria 

 diurna. If it is not, he argues, then there must be another blood 

 worm yet to be discovered, for the embryos of the loa must escape 

 from the body of their host through the medium of the circulation. 

 Filaria perstans has been practically proved by Manson to be the 

 cause of the fatal " sleeping sickness" of the Congo region. 



While engaged in the study of filariasis my attention was called 

 by Dr. Charles A. Oliver of Philadelphia, to a remarkable case of 

 Filaria loa recently reported by Dr. Argyll Robertson, the distin- 

 guished ophthalmologist of Edinburgh. The patient was a lady 

 who had spent eight years in missionary work at Old Calabar on 



