THE BEAUTIFUL LADDER. 
245 
possess neither square nor dividers, only feet, 
bill, and breast, to aid them in their work. 
The most varied materials are used, and are 
selected and appropriated with special care as 
the different conditions and stages of progress 
require. Now a foundation of sticks or mud, 
as used by the robin, and now moss, grass, 
leaves, and any soft woolly fibre, lint, wool, 
cotton, or down of flowers. Others use a glu¬ 
tinous secretion or transparent jelly, as in the 
edible swallows’ nests so highly prized as a del¬ 
icacy by the Chinese. But, with the exception 
of a few species which lay their eggs on the 
ground, whatever may be the materials used in 
the main structure, the final inner finish is of 
the softest texture that can be obtained, even 
in some cases, as among the humming-birds, the 
dainty web of the spider. Whatever requisites 
may be used, they are assorted and worked into 
the structure with art that no human skill can 
equal. If this statement is questioned, let the 
doubter try his hand on the nest of a robin 
or an oriole, and he will find his best efforts at 
imitation abortive. 
“ In studying these characteristics of birds no 
thoughtful observer can fail to realize the force 
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