The ripple beat gently on the sea-line of the boat, which oscillated with the regularity and softness of a cradle.
"It is always so," said Jack, impatiently; "if we don't want wild beasts, there are shoals of them to be seen; but if we do want them, then they are all off to their dens." "Perhaps, there are none now," suggested Willis.
"Say rather," observed Fritz, "that there ought to be thousands; for on the one hand they multiply rapidly, and on the other there is no one to destroy them.

Spaniards once left a few cattle on St.Domingo, and they increased at such a rate, that the island very soon would not have been able to support them, had they not been kept down by constant slaughter." "Besides," remarked Jack, "the bovine race reproduce themselves more slowly than other animals; a single sow, according to a calculation made by Vauban, if allowed to live eleven years, would produce six millions of pigs." "What a cargo of legs of pork and sides of bacon!" exclaimed Willis, laughing.
"Then fish; there are more than a hundred and sixty thousand eggs in a single carp.

A sturgeon contains a million four hundred and sixty-seven thousand eight hundred and fifty, whilst in some codfish the number exceeds nine millions." "Oh, you need not favor us with the 'Mariner's March,' Willis; what my brother says is perfectly correct." "What, then, do these shoals of creatures live upon ?" "The big ones upon the little ones; fish devour each other." "A beautiful harmony of Nature," remarked Fritz drily.
"Then plants," continued Jack, "are still more prolific than animals.
Some trees can produce as many of their kind as they have branches, or even leaves.

An elm tree, twelve years old, yields sometimes five hundred thousand pods; and, by the way, Willis, to encourage you in carrying on the war against the mosquitoes, a single stalk of tobacco produces four thousand seeds." "The leaves, however, are of more use to me than the seeds," replied Willis.
"This admirable proportion between the productiveness of the two kingdoms demonstrates the far-seeing wisdom of Providence.

If the power of multiplication in vegetables had been less considerable, the fields, gardens, and prairies would have been deserts, with only a plant here and there to hide the nakedness of the land.