se continuously and are at once
replaced by others in the generating casket; slowly they rise, like tiny
globes of light. They spread on every side. It is a constant display of
fireworks in the depths of the water.

Chemistry tells us that, thanks to its green matter and the stimulus of
the sun's rays, the weeds decompose the carbonic acid gas wherewith
the water is impregnated by the breathing of its inhabitants and the
corruption of the organic refuse; it retains the carbon, which is
wrought into fresh tissues; it exhales the oxygen in tiny bubbles. These
partly dissolve in the water and partly reach the surface, where their
froth supplies the atmosphere with an excess of breathable gas. The
dissolved portion keeps the colonists of the pond alive and causes the
unhealthy products to be oxidized and disappear.

Old hand though I be, I take an interest in this trite marvel of a
bundle of weeds perpetuating hygienic principles in a stagnant pool;
I look with a delighted eye upon the inexhaustible spray of spreading
bubbles; I see in imagination the prehistoric times when seaweed, the
first-born of plants, produced the first atmosphere for living things
to breathe at the time when the silt of the continents was beginning to
emerge. What I see before my eyes, between the glass panes of my trough,
tells me the story of the planet surrounding itself with pure air.

CHAPTER VIII. THE CADDIS WORM

Whom shall I lodge in my glass trough, kept permanently wholesome by
the action of the water weeds? I shall keep caddis worms, those expert
dressers. Few of the self-clothing insects surpass them in ingenious
attire. The ponds in my neighborhood supply me with five or six species,
each possessing an art of its own. Today, but one of these shall receive
historical honors.

I obtain it from the muddy bottomed, stagnant pools crammed with small
reeds. As far as one can judge from the habitation merely, it should be,
according to the specialists, Limnophilus flavicornis, whose work has
earned for the whole corporation the pretty name of Phryganea, a Greek
term meaning a bit of wood, a stick. In a no less expressive fashion,
the Provencal peasant calls it lou portofais, lou porto-caneu. This is
the little grub that carries through the still waters a faggot of tiny
fragments fallen from the reeds.

Its sheath, a travelling house, is a composite and barbaric piece of
work, a megalithic pile wherein art, retires in favor of amorp