54 
LIFE, IN ITS LOWER FORMS. 
the economy of these animals which appeared so anoma- 
lous, was the mode in which they were both naturally 
and artificially multiplied. They were manifestly animals, 
yet it was found that they could he propagated by slips 
or cuttings, like plants ! In the warm weather of sum- 
mer each polype is observed to shoot forth, from various 
parts of its body, little warts, or knobs, which increase 
rapidly, until in a few days they assume the form of the 
parent animal, each one being furnished with a circle of 
tentacles, though still attached at its lower end. The 
young one, which up to this period had received its nutri- 
ment from the parent’s stomach, from which a channel 
had communicated with its own, now catches prev with 
its own tentacles, the duct closes, the connexion of the 
base with the mother becomes more slender, and at length 
the little animal falls off, and commences independent 
life. Such is the ordinary mode of increase — generation 
by gemmation. 
In autumn, the Hydra propagates by means of eggs, 
which are deposited around the parent ; the basal portion 
of her body being spread over them, and becoming a horny 
protecting skin. She immediately dies, and the eggs are 
hatched in the ensuing spring.* 
But these strange animals may be artificially increased 
at pleasure, and that by means which, to higher animals, 
would inevitably destroy, instead of multiplying life. If 
the head of a polype, with all its tentacles, be cut off from 
the trunk with scissors, it will presently develop a new 
trunk and base, while the headless trunk begins to shoot 
out new tentacles ; and thus, in a little time, two perfect 
* Laurent, L’lustitut, No. 465. 
