﻿OBSERVATIONS UPON FILAUIA PHILIPPINENSIS. 6 



spot and the tip becomes suddenly attenuated to three quarters of its former diam- 

 eter, thus forming a distinct offset upon each side; from this point the tail dimin- 

 ishes progressively and uniformly to a very fine, thread-like point. Because of 

 its situation in relation to the embryonic anus and its apparently less vital char- 

 acteristics, the portion of the tail beyond the attenuation probably dies or is 

 sloughed off during the later development of the filaria. 



In. stained specimens, a column of deeply stained nuclei is observed running the 

 entire length of the worm, broken here and there by unstained areas, which vary 

 in position in individual specimens; the only "gap" in the stained column that is 

 at all constant is situated at a point 20 per cent of the total length of the 

 worm from the head; however, many specimens do not show this "gap," and there 

 is also much variation in its situation in individual filaria. We do not regard it 

 as of any diagnostic importance. In the stained specimen the anterior V spot, the 

 central viscus, and the posterior V spot are not seen. 



Filaria philippinensis is very actively motile, the movements being of a wrig- 

 gling, lashing character and not progressive, as a rule, but at times a marked 

 progressive motion is observed. (See figs. 1 and 18.) 



LATER OBSERVATIONS. 



The study of four more cases of infection with Filaria philippinensis 

 has enabled its to add somewhat to the above description as regards the 

 morphology, motility, and periodicity of this filaria. 



Morphology. — We can add but little to our original description as 

 regards the morphology of Filaria philippinensis. We have examined a 

 very large number of filarise in the blood with special reference to the 

 armature of the head, but we have been unable to distinguish any definite 

 number of lips; the spicule, mounted upon a smooth, hemispherical base, 

 into which it retracts, is easily distinguished, but the retractile prepuce 

 which incloses it can not be separated into definite lips, its margin 

 being so very finely serrated. The serrations can easily be seen in the 

 fresh specimen, but their number can not be determined, while in the 

 stained specimen they are not visible. 



In a certain proportion of stained filarise in blood obtained from the 

 mosquito's stomach shortly after the insect has bitten, and in which 

 the sheath has been lost, what appears to be two lips can be seen, an upper 

 one, broad and fleshy, and a lower, more slender and delicate. However, 

 we are not convinced that these represent true lips, for the appearance 

 may be due to the staining method, but their presence in a comparatively 

 large number of the filarial is suggestive. 



The sheath, as we have already stated, is tight and generally only seen 

 as a thread-like flagellum at the extremities of the worm. When the 

 filaria is moving forward, the anterior end of the sheath bends backward 

 along the side of the body, while the posterior end is lashed about by the 

 movement of the tail ; when the movements of the worm are lashing and 

 not progressive, both ends of the sheath are whipped freely about. The 

 filaria is never seen to slide forward and backward within the sheath, 



