276 ON THE CLASSIFICATION OF BIRDS. 
may be changed, and they may be raised higher or 
lower, as circumstances require. The glass front should 
be easily taken off ; or it may be hung on hinges, the 
sides being lined with felt or baize, so that as little air 
or dust can enter as possible. It is surprising how 
closely birds of a moderate size may he arranged on 
this plan without any appearance of confusion, each 
specimen being immediately accessible, and capable of 
being taken out singly in three minutes. Of two cases 
now before us, one, containing a large proportion of 
small birds, has seventy-five specimens ; ^e other, 
chiefly filled with thrushes, starlings, and other middle- 
sized birds, contains fifty-two. The dimensions of 
each case are three feet eleven inches high, three feet 
one inch wide, and eleven inches deep. 
(228.) But even the above method of arranging a 
large collection, admirable as it is, presents some serious 
obstacles to a private individual, no less than to socie- 
ties whose funds are not very ample. It requires great 
space, and a large pecuniary expenditure. Rooms or 
galleries must be devoted to containing cases; and 
the cost of mounting, independent of the eases them- 
selves, will generally be found, in a large collection, to 
average nearly two thirds the original cost of the speci- 
mens. The great and con.stant trouble, also, of opening 
glass fronts whenever a bird is to be examined, is no 
small hinderance to the scientific author, who often 
finds it necessary to be able to handle a specimen, turn 
it about, open its wings or tail, and discompose in some 
measure that exact arrangement of the feathers which 
constitutes the finishing of a mounted specimen. All 
these, as we before observed, are serious inconveniences 
to all but very wealthy individuals, who can build 
galleries and rooms, and to whom the expense of mount- 
ing is no object. 
( 229 -) last and best method of arranging birds 
is by leaving them, as it is technically called, “ in their 
skins.” It is now near twenty years since we began 
this plan, to the great surprise and disapprobation of 
