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.

1. They respire by orifices in the sides of the body, known to naturalists as stigmata. The whole body, Cuvier says, forms, in a measure, a system of lungs.

2. Cuvier remarks that the various noises made by insects are in reality not the voice, as they are not produced by air passing through a larynx.

3. B. ix. c. 6.

4. Cuvier remarks, that they have a nourishing fluid, which is of a white colour, and acts in place of blood.

5. The dye of sæpia, Cuvier remarks, is not blood, nor does it act as such, being an excrementitious liquid. It has in addition a bluish, transparent, blood. The same also with the juices of the purple.