CHAP. 2. (3.)—WHETHER INSECTS RESPIRE, AND WHETHER
THEY HAVE BLOOD.
Many authors deny that insects respire,
1 and make the
assertion upon the ground, that in their viscera there is no
respiratory organ to be found. On this ground, they assert
that insects have the same kind of life as plants and trees,
there being a very great difference between respiring and merely
having life. On similar grounds also, they assert that insects
have no blood, a thing which cannot exist, they say, in any
animal that is destitute of heart and liver; just as, according
to them, those creatures cannot breathe which have no lungs.
Upon these points, however, a vast number of questions will
naturally arise; for the same writers do not hesitate to deny
that these creatures are destitute also of voice,
2 and this,
notwithstanding the humming of bees, the chirping of grasshoppers, and the sounds emitted by numerous other insects
which will be considered in their respective places. For my
part, whenever I have considered the subject, I have ever felt
persuaded that there is nothing impossible to Nature, nor do I
see why creatures should be less able to live and yet not
inhale, than to respire without being possessed of viscera, a
doctrine which I have already maintained, when speaking
3 of
the marine animals; and that, notwithstanding the density
and the vast depth of the water which would appear to impede
all breathing. But what person could very easily believe that
there can be any creatures that fly to and fro, and live in the
very midst of the element of respiration, while, at the same time,
they themselves are devoid of that respiration; that they can
be possessed of the requisite instincts for nourishment, generation, working, and making provision even for time to come,
in the enjoyment too (although, certainly, they are not possessed of the organs which act, as it were, as the receptacles
of those senses) of the powers of hearing, smelling, and tasting, as well as those other precious gifts of Nature, address,
courage, and skilfulness? That these creatures have no blood
4
I am ready to admit, just as all the terrestrial animals are not
possessed of it; but then, they have something similar, by way
of equivalent. Just as in the sea, the sæpiahas
5 a black
liquid in place of blood, and the various kinds of purples, those
juices which we use for the purposes of dyeing; so, too, is every
insect possessed of its own vital humour, which, whatever it
is, is blood to it. While I leave it to others to form what
opinion they please on this subject, it is my purpose to set
forth the operations of Nature in the clearest possible light,
and not to enter upon the discussion of points that are replete
with doubt.