The Infusoria reproduce their species in several ways: by a kind of budding, like plants, by sexual reproduction, and by fission—i.e., the spontaneous division of the animal into two parts. “By this mode of propagation,” says Dujardin, “an Infusorian is the half of the one which preceded it, the fourth of the parent of that, the eighth of its grandparent, and so on.” The process is represented in the accompanying [pg 113]figures, A and B being the adult, C the same in course of separation, and D after completion. “This mode of generation, however,” says Figuier, “enables us to comprehend the almost miraculous multiplication of these beings. The amount defies calculation, if we wished to be at all precise. We may, however, arrive at a proximate estimate of the number which may be derived from a single individual by this process of fission. It has been found that at the end of a month two Stylonichiæ would have a progeny of more than 1,048,000 individuals, and that in a lapse of forty-two days a single Paramecium could produce much more than 1,364,000 forms like itself.” In a year it would have the proud satisfaction of being the father of an Infusorian nation!
PROPAGATION OF AN INFUSORIAN BY SPONTANEOUS DIVISION.
Many of the Infusoria are subject to metamorphoses, while others can remain long periods, and in a dried and torpid state, and then awake to action. One of the largest of these curious organisms, which sometimes actually attains to the size of the twelfth of an inch, is the Kondylostoma patens, remarkable for its voracity. It lives upon sea-weed, and is common to every shore, from the Mediterranean to the Baltic.
KONDYLOSTOMA PATENS (MAGNIFIED 300 TIMES).
The inhabitants of the sea are, there can be no doubt, much more numerous than those of the earth. Charles Darwin has remarked that our terrestrial forests do not maintain nearly so many living beings as do marine forests in the very bosom of the ocean. Its surface and its depths, its plains and its mountains, its valleys and precipices, teem with organisms, the like of which have no counterpart on the land, and which are only partly understood to-day, although the invention and adoption of the aquarium have greatly facilitated the study of them.
Many years ago Dr. Milne-Edwards, in a voyage round the coast of Sicily, employed a diver’s apparatus to enable him to descend and examine the bottom of the sea. It included a metallic casque and helmet, with visor or window of glass fitting closely by means of water-tight packing round the neck. It communicated with an air-pump above by a flexible tube; the diver had a rope attached by which he could be hoisted immediately, and a signal cord to give alarm in case of need; he wore heavy lead shoes, which gave him steadiness and enabled him to maintain his upright position in the water. Milne-Edwards made the descent in several fathoms of water, and with perfect safety. Ariel’s song had not to be applied to him:—
“Full fathoms five thy father lies;
Of his bones are coral made;