NESTS AND EGGS. 
vegetable fibre. These are only a few of the facts which 
may be adduced to prove that birds are gifted with an 
instinctive power of selecting materials and positions calculated 
to conceal their eggs and progeny from their enemies. By far 
the most numerous class of birds build their nests in trees or 
bushes, and a nest, in spite of the arts of the builders, being 
a bulky excrescence, is easily discovered by a practised eye, 
and, once discovered, concealment of the eggs would be 
impossible. 
As to the eggs themselves, their well-known external cover- 
ing is a light, porous, and brittle shell, of chalky formation, 
which is pervious to the admission of oxygen and carbonic acid 
from the atmosphere, which are essential to the development of 
the vital principle which they contain. Within the shell is a 
thin membraneous lining, which covers the whole, terminating 
in a small bag at the obtuse end, which receives the air and 
communicates with the interior organism of the egg. Within 
this lining is the white, or albumen, which, under the 
microscope, reveals some very curious physiological forms, 
which it would be foreign to our purpose to enter on here. 
Within this layer is the yellow matter, known as the yolk or 
vitellus of the egg. 
An examination of the statistics of eggs leads to the conclu- 
sion that the birds useful to man produce them in the greatest 
numbers. The domestic fowl and the gallinaceous tribes gene- 
rally lay an unlimited number of eggs; those smaller birds 
which live on insects, as if for the purpose of keeping down 
these enemies to vegetation, lay a large but limited number of 
eggs. In falcons and owls the number varies from two to five, 
the largest and fiercest birds having the fewest eggs. 
But our present object is to collect and prepare eggs and 
nests. The pursuit is sometimes objected to on the score of 
inhumanity; but it is not impossible to gratify a rational 
curiosity and avoid the other alternative. One or two eggs 
taken from a nest does not, probably, much affect the mother 
bird : taking the whole nest, indeed, in some species, only leads 
to their building a second ; for it seems pretty well ascertained 
that most birds, after a time, will build a second and even a 
third time, although at each successive laying the eggs are 
said to be smaller and less numerous. We cannot, then, advise 
our bird-nesters to take more than one or two eggs from any 
one nest, and the only excuse for taking the nest itself is when 
a collection is being formed ; even then, if possible, let the nest 
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