be other powers at play
in the tiny animal's machinery.

Total abstinence from food could be understood, if it were accompanied by
inertia: immobility is not life. But the young Lycosae, although usually
quiet on their mother's back, are at all times ready for exercise and for
agile swarming. When they fall from the maternal perambulator, they
briskly pick themselves up, briskly scramble up a leg and make their way
to the top. It is a splendidly nimble and spirited performance. Besides,
once seated, they have to keep a firm balance in the mass; they have to
stretch and stiffen their little limbs in order to hang on to their
neighbours. As a matter of fact, there is no absolute rest for them. Now
physiology teaches us that not a fibre works without some expenditure of
energy. The animal, which can be likened, in no small measure, to our
industrial machines, demands, on the one hand, the renovation of its
organism, which wears out with movement, and, on the other, the
maintenance of the heat transformed into action. We can compare it with
the locomotive-engine. As the iron horse performs its work, it gradually
wears out its pistons, its rods, its wheels, its boiler-tubes, all of
which have to be made good from time to time. The founder and the smith
repair it, supply it, so to speak, with 'plastic food,' the food that
becomes embodied with the whole and forms part of it. But, though it
have just come from the engine-shop, it is still inert. To acquire the
power of movement, it must receive from the stoker a supply of 'energy-
producing food;' in other words, he lights a few shovelfuls of coal in
its inside. This heat will produce mechanical work.

Even so with the beast. As nothing is made from nothing, the egg
supplies first the materials of the new-born animal; then the plastic
food, the smith of living creatures, increases the body, up to a certain
limit, and renews it as it wears away. The stoker works at the same
time, without stopping. Fuel, the source of energy, makes but a short
stay in the system, where it is consumed and furnishes heat, whence
movement is derived. Life is a fire-box. Warmed by its food, the animal
machine moves, walks, runs, jumps, swims, flies, sets its locomotory
apparatus going in a thousand manners.

To return to the young Lycosae, they grow no larger until the period of
their emancipation. I find them at the age of seven months the same as
when I saw them at their birth