The genus Volvox--the little worms or wormlets in vinegar, mud, spoiled paste, or grain-smut; the Rotifera--a kind of little shell-fish protected by a carapace, provided with a good digestive apparatus, of separate sexes, having a nervous system with a distinct brain, having either one or two eyes, according to the genus, a crystalline lens, and an optic nerve; the Tardigrades--which are little spiders with six or eight legs, separate sexes, regular digestive apparatus, a mouth, two eyes, a very well defined nervous system, and a very well developed muscular system;--all these die and revive ten or fifteen times consecutively, at the will of the naturalist.

One dries up a rotifer: good night to him; somebody soaks him a little, and he wakes up to bid you good day.

All depends upon taking great care while he is dry.

You understand that if any one should merely break his head, no drop of water, nor river, nor ocean could restore him.
"The marvellous thing is, that an animal which cannot live more than a year, like the minute worm in grain-smut, can lie by twenty-four years without dying, if one has taken the precaution of desiccating him.
"Needham collected a lot of them in 1743; he presented them to Martin Folkes, who gave them to Baker, and these interesting creatures revived in water in 1771.

They enjoyed a rare satisfaction in elbowing their own twenty-eighth generation.