312 HINTS TO ORNITHOLOGISTS. 
the study of internal anatomy to be the basis of the 
zoological system. 
We may measure the feet of preserved bird-skins j 
with rule and compasses, and then draw the conclu- I 
sion, from external appearances, that this foot, foi". I 
sooth^ is gifted by Nature fo^ grasping, and that, for ; 
perching : but it will not do. Internal anatomy must 
be consulted. It alone can let us into the real secret, | 
why all birds which frequent the trees can grasp a ' 
branch with the utmost facility, and sit securely 
there, without any fear of falling from it. 
See the barn-door fowl walking before us I No 
sooner does it lift its foot from the ground, than the | 
toes immediately bend inwards. From this natural 
tendency to contract we draw the conclusion, that a 
bird is in absolute security when it perches upon a i 
branch. By means of this admirable provision of 
Nature, the little delicate golden-crested wren can 
brave the raging tempest, on the top of the loftiest 
tree, in as perfect safety as the largest bird of the 
creation. 
Nothing can be more illusory than an attempt to 
judge of a bird's powers of perching by an external 
admeasurement of its feet and claws. Our specula- 
tion is unprofitable, and our judgment is of no avail 
whatever ; for, after we have laid our rule and com- 
passes down upon the table, and have left the house | 
to take a walk into the fields, with a full conviction ! 
that we have learned our lesson from the dried skin 
of a bird, we find that the habits of one bird are 
utterly at variance with those of another, although i 
the proportional anatomy of their feet and claws 
