bles contain an
acrid and volatile oil, which gives them strong anti-scorbutic
qualities. The cabbage (_Brassica oleracea_), turnip (_B. napus_),
radish (_Raphanus sativus_), and mustard (_Sinapis alba_), are of the
crucifera order. To this list we must also add the horse-radish, the
colza, the seed of which produces an oil well adapted for lighting
purposes; the _crysimum_, or hedge-mustard, a popular remedy in France
for coughs; the shepherd's purse, which the Mexicans use as a decoction
for washing wounds; and the _Lepidium piscidium_, employed by the
natives of Oceanica for intoxicating fish, so as to catch them more
easily.

"You quite forget the _cochlearia_, or scurvy-grass, so useful to
sailors as a remedy for scurvy?" said Sumichrast.

"You are right; but I think I've said enough about the _Cruciferae_ for
Master Sunbeam to remember."

A few paces farther on, while we were looking for insects under the
leaves of a shrub, Lucien drew back in surprise at seeing it covered
with the pretty little creatures called tree-frogs (_Hyla viridis_).
Instead of flying towards the water, these reptiles made for the woods.
Sumichrast explained to the young naturalist that tree-frogs have sticky
disks on their feet, and by the aid of this mechanism they could move
about on leaves and even on smooth surfaces.

"In Europe," he added, "the peasants shut them up in bottles half full
of water, and assert that the animal predicts good or bad weather by
either coming up to the top or keeping under the water. The tree-frog,
like all its fellows, buries itself in the mud during winter, and
remains torpid. This lethargy, which in glacial climates has the effect
of preserving it from hunger, must in Mexico have some other cause, for
in the latter country it can find food all the year round. The skin of
the tree-frog secretes a poisonous matter."

"Come here and look at an apple-tree!" cried Lucien, suddenly.

I hastened to the spot, and found a shrub about thirteen or fourteen
feet high, covered with berries of a yellowish color, spotted with red.
I recognized what is called in the Antilles the soap-tree. This
discovery came just in the nick of time, and Sumichrast helped us in
gathering some of the useful fruit which would assist us to give our
clothes a thorough wash. Lucien tasted the little apples, which were as
transparent as artificial fruit made of pure wax; but he did not like
their astringent flavor, and threw them away w