Essays on the Microscope: Containing a Practical Description of the Most Improved Microscopes, a General History of Insects, etc., etc.Adams, George
Science
Essays on the Microscope: Containing a Practical Description of the Most Improved Microscopes, a General History of Insects, etc., etc.
Adams, George
Insects -- Early works to 1800; Microscopy -- Early works to 1800
provided with a liquor with which they soften and weaken the end of the
cone; some leave one end feeble, and close it only with a few threads,
so that a slight effort of the head enables the moth to burst the prison
doors, and immerge into day.
When the moth first sees the day, it is humid and moist; but this
humidity soon evaporates, the interior parts dry and harden as well as
the exterior; the wings, which are wrinkled, being thick and small, then
extend themselves, strengthen and harden insensibly, and the fibres
which were at first flexible, become hard and stiff; so much so, that
Malpighi considered them as bones: in proportion as these fibres harden,
the fluid which circulates within them, and extends the wings, loses its
force; so that if any extraneous circumstance prevent the motion of this
fluid, at the first instant of the moth’s escape from its former state,
the wings will then become ill-shaped; often expanding with such
rapidity, that the naked eye cannot trace their unfolding. The wings,
which were scarce half the length of the body, acquire in a few minutes
their full size, so as to be nearly five times as large as they were
before: nor is it the wings only which are thus increased; all their
spots and colours, heretofore so minute as to be scarce discernible, are
proportionably extended, so that what before appeared as only so many
unmeaning and confused points, become distinct and beautiful ornaments;
and those that are furnished with a tongue or trunk, curl and coil it
up. When the wings are unfolded, the tongue rolled up, the moth
sufficiently dried, and the different members strengthened, it takes its
flight. Most of them, soon after they have attained their perfect state,
void an excrementitious substance; Reaumur thinks that they eject very
little, if any, during the rest of their lives.
In the progress of these insects, such changes take place, as we could
have formed no conception of, if the great Author of these wonders had
not been pleased to reward the industrious naturalist with the
discovery.
If the moth be opened down the belly, and the unctuous parts which fill
it, be removed, the gross artery, which has been called the heart, will
be visible, and the contractions and dilatations, by which it pushes
forward the liquor it contains, may be easily observed. One of the most
remarkable circumstances is, that the circulation of this fluid in the
moth is directly contrary to that which took place in the caterpillar;
in this, the liquor moved from the tail to the head, whereas in the
moth, it moves from the head to the tail; so that the fluid which
answers the purposes of the blood in the moth, goes from the superior,
towards the inferior parts, but in the voracious sensual caterpillar,
the order is inverted, it proceeds from the inferior towards the
superior parts; all its members, formerly soft, inactive, and folded up
under an envelope, are expanded, strengthened, and exposed to
observation.
Public-domain text, read in full here on John Shaqi.
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