many authors deny that insects breathe, upon the ground that in their viscera there is no respiratory organ[188] to be found. 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,[189] 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 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 235 instincts for nourishment, working, and making provision even for time to come, in the enjoyment too 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 i am ready to admit, just as all the terrestrial animals are not possessed of it; but they have something similar, by way of equivalent.[190]

insects, so far as i find myself able to ascertain, seem to have neither sinews,[191] bones, spines, cartilages, fat, nor flesh; nor yet so much as a frail shell, like some of the marine animals, nor even anything that can with any propriety be termed skin; but they have a body which is of a kind of intermediate nature between all these, of an arid substance, softer than muscle, and in other respects of a nature that may, in strictness, be rather pronounced yielding, than hard. such, then, is all that they are, and nothing more: in the inside of their bodies there is nothing, except in a few, which have an intestine arranged in folds. hence, even when cut asunder, they are remarkable for their tenacity of life, and the palpitations which are to be seen in each of their parts. for every portion of them is possessed of its own vital principle, which is centred in no limb in particular, but in every part of the body; least of all, however, in the head, which alone is subject to no movements unless torn off together with the corselet. no kind of animal has more feet than the insects have, and those which have the most, live the longest when cut asunder, as we see in the case of the scolopendra. they have eyes, as well the senses of touch and taste; some of them have also the sense of smelling, and a few that of hearing.