LECTURE XII. 193 



The lately instituted genus Filaria is so simi- 

 lar to that of Gordius or Hair- Worm, that it can 

 hardly be separted from it with propriety. Some 

 species of Filaria inhabit the waters, and some are 

 found in the bodies of animals ; even in those of 

 insects ; many kinds of Beetles and Caterpillars 

 being infested by them. Among those which in- 

 fest the waters, the most common is the Horse- 

 Hair Worm, so called from its general appearance, 

 usually measuring several inches in length, and 

 being of a dusky colour, and not much thicker 

 than a horse-hair. It is the Gordius aquaticus of 

 Linnaeus, and is in many places believed by the 

 common people to be an animated horse-hair. Lin- 

 naeus observes that in Sweden an idea prevails of its 

 bite, or rather its puncture, producing the com- 

 plaint called a Whitlow; and this he says was verified 

 in the case of a Mr. Rinmann. I have likewise my- 

 self been witness to an instance of a similar nature, 

 in which the animal, on being taken out of the wa- 

 ter, pierced the tip of the finger, near the nail, and 

 a whitlow was the consequence of the puncture; but 

 whether the same complaint might not have taken 

 place from the puncture of any other substance on 

 the same part, I cannot take upon me to determine. 



LECT. II. O 



