He certainly had a lucky inspiration who first thought of confining the wind in a bag, as mythology tells us that Æolus did. The goatskin turned into a bellows gave us our metals, the essential matter whereof our tools are made. Well, in this art of expelling air, an enormous source of progress, the Cicadella was the pioneer. She was blowing her froth before Tubalcain thought of urging the fire of his forge with a leather pouch. She was the first to invent bellows. When, bubble by bubble, the foamy wrapper covers the insect to a height which the uplifted tip of her belly is unable to reach, it is no longer possible to take in air and the effervescence stops. Nevertheless, the gimlet that extracts the sap goes on working, for nourishment must be obtained. As a rule then, in the sloping part, the superfluous liquid, that which is not converted into foam, collects and forms a drop of perfectly clear liquid. What does this limpid fluid lack in order to turn white and effervesce? Nothing but air blown into it, one would think. I am able to substitute my own devices for the Cicadella’s syringe. I place between my lips a very slender glass tube and with delicate puffs send my breath into the drop of moisture. To my great surprise, it does not froth up. The result is just the same as that which I should have with plain water from the tap. Instead of a plentiful, lasting, slow-subsiding foam, like that with which the insect covers itself, all that I obtain is a miserable ring of bubbles, which burst as soon as they appear. And I am equally unsuccessful with the liquid which the Cicadella collects under her abdomen at the start, before working her bellows. What is wrong in each case? The foamy product and its generating liquid shall tell us. The first is oily to the touch, gummy and as fluid as, for instance, a weak solution of albumen would be; the second flows as readily as plain water. The Cicadella therefore does not draw from her well a liquid liable to effervesce merely by the action of the blow-pocket; she adds something to what oozes from the puncture, adds a viscous element which gives cohesion and makes frothing possible, even as a boy adds soap to the water which he blows into iridescent bubbles through a straw. Where then does the insect keep its soap-works, its manufactory of the effervescent element? Evidently in the blow-pocket itself. It is here that the intestine ends and here that albuminous products, furnished either by the digestive canal or by special glands, can be expelled in infinitesimal doses. Each whiff sent out is thus accompanied by a trifle of adhesive matter, which dissolves in the water, making it sticky and enabling it to retain the captive air in permanent bubbles. The Cicadella covers herself with an icing of which her intestine is to some extent the manufacturer.