LECTURE XIL 
193 
The lately instituted genus Filaria is so simi- 
lar to that of Goy'dius 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 5 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 
