THE TRANSFORMATION. 
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of color or beauty. How are they to expand 
and become vigorous and ready for flight? I 
will tell you. 
The wing of the butterfly is composed of two 
membranes, that at first do not touch each other, 
but leave a space between. This hollow space 
has a number of tubes or vessels, called nervures 
running through it, and when the nervures are 
empty, as they are at present, the wings droop, 
and have neither power nor beauty. 
But presently, a fluid, that answers to the blood 
in animals, begins to rush through them; the air 
also gains admittance and fills the air-vessels; 
and a wonderful change takes place. The wings 
that were folded and doubled up, gradually open 
and expand, for the fluid is forcing its way into 
every nervure, and the nervures themselves are 
increasing in size as the wing is. 
Everything depends on the proper circulation of 
the fluid; and there is one conjecture about it 
that I ought not to pass over, though it does not 
relate to the butterfly. 
When the emperor moth comes out of her 
cocoon, it has been supposed, that the trap of 
spikes, set round the doorway, press upon her 
body, and assist in forcing the fluid into her 
wings. This seems very likely to be the case, 
for a chrysalis was once taken out of the 
cocoon, and the moth hatched, without being 
