38 Henry B. Ward 



have each its own territory and so far as present records show 

 do not occur together in any region. 



The occurrence of Filaria loa in negro slaves, in travelers, in 

 government officials, and in missionaries points out distinctly 

 the certainty with which any kind of intercourse between nations 

 and geographic areas tends to transfer to new races and terri- 

 tories the diseases of the old. Increased means of communica- 

 tion and growing freedom of movement contribute clearly to 

 the spread of maladies and call for better means to check their 

 advance into new regions. It is not to be doubted that some 

 of the persons who brought F. loa into the United States now 

 harbor its embryos in the blood. Though we know nothing pre- 

 cise of its life history, the possibility lies close at hand that some 

 blood-sucking insect may furnish these embryos proper condi- 

 tions for further development and may thus bring about the 

 introduction of a new disease into our territory. Such cases as 

 these of F. loa show clearly the gradual spread of disease 

 through national intercourse. 



4. Pathology ^ 



seat of the parasite 



In many cases no more definite information is given than that 

 the parasite occurred in the eye. In the absence of more specific 

 details this may probably be construed to mean crossing the eye- 

 ball beneath the conjunctiva but above the cornea or sclerotic; 

 in numerous cases, indeed, such a location is definitely assigned 

 to the parasite. All in all, this is the most usual position of 

 F. loa in the cases thus far on record ; however, for reasons to 

 be fiven later it is probably only an accidental occurrence and 

 not the normal seat of the parasite. While most frequently 

 recorded on the surface of the eyeball yet accurate records are 

 not wanting to show that the parasite does occur, if infrequently, 

 within the bulbus oculi. From the anterior chamber F. loa was 

 removed in the case of Mercier (No. 4, but not in No. 5 as 

 Kraemer incorrectly says), also in the case of Bachelor (No. 

 27), of Lacompte (No. 33), and possibly of Barkan, if this most 

 doubtful account be interpreted as concerning F. loa. 



308 • 



