ngs considered, there is not a doubt but that the Glow-worm
himself manages his lighting-apparatus, extinguishing and rekindling
it at will; but there is one point at which the voluntary agency of
the insect is without effect. I detach a strip of the epidermis
showing one of the luminescent sheets and place it in a glass tube,
which I close with a plug of damp wadding, to avoid too rapid an
evaporation. Well, this scrap of carcass shines away merrily, although
not quite as brilliantly as on the living body.

Life's aid is now superfluous. The oxidizable substance, the
luminescent sheet, is in direct communication with the surrounding
atmosphere; the flow of oxygen through an air-tube is not necessary;
and the luminous emission continues to take place, in the same way as
when it is produced by the contact of the air with the real phosphorus
of the chemists. Let us add that, in aerated water, the luminousness
continues as brilliant as in the free air, but that it is extinguished
in water deprived of its air by boiling. No better proof could be
found of what I have already propounded, namely, that the Glow-worm's
light is the effect of a slow oxidization.

The light is white, calm and soft to the eyes and suggests a spark
dropped by the full moon. Despite its splendour, it is a very feeble
illuminant. If we move a Glow-worm along a line of print, in perfect
darkness, we can easily make out the letters, one by one, and even
words, when these are not too long; but nothing more is visible beyond
a narrow zone. A lantern of this kind soon tires the reader's
patience.

Suppose a group of Glow-worms placed almost touching one another. Each
of them sheds its glimmer, which ought, one would think, to light up
its neighbours by reflexion and give us a clear view of each
individual specimen. But not at all: the luminous party is a chaos in
which our eyes are unable to distinguish any definite form at a medium
distance. The collective lights confuse the link-bearers into one
vague whole.

Photography gives us a striking proof of this. I have a score of
females, all at the height of their splendour, in a wire-gauze cage in
the open air. A tuft of thyme forms a grove in the centre of their
establishment. When night comes, my captives clamber to this pinnacle
and strive to show off their luminous charms to the best advantage at
every point of the horizon, thus forming along the twigs marvellous
clusters from which I expected magnif