60 
OIL GLANDS OF BIRDS. 
ON BIRDS USING OIL FROM GLANDS FOR 
THE PURPOSE OF LUBRICATING THE SUR- 
FACE OF THEIR PLUMAGE." 
*' Nardo perunctus.'* Hor. Epod. 
Birds, in general, are much troubled with vermin. 
After applying the solution of corrosive sublimate 
in alcohol to he fresh skin of a bird, you will see 
an amazing quantity of insects coming out from all 
parts of the plumage, but especially from the head. 
They linger for a few hours on the extremities of 
the feathers, and then fall off and die : they are of 
all sizes, from the full-grown insect down to the 
minutest little creature which has just entered into 
life and motion. No part of the body of the bird is 
exempt from their annoyance ; and we may judge 
how much the birds suffer from it, by their perpe- 
tual attempts to free themselves from the tormenting 
attacks of the insects. 
People are apt to suppose that a bird is preening, 
or rectifying, its feathers, when they see it applying 
its bill to the plumage, and running it down a fea- 
ther, from the root to the extremity : but a man 
well versed in the habits of birds knows, when he 
sees the bird do this (except after it has got wet), 
that it is trying to dislodge the vermin, which cling 
with an astonishing pertinacity to the feathers. 
Now, while the bird is thus employed on that part 
of its body just above the tail, where there is a 
gland, some people imagine that the bird is pro- 
