of the universe. We are more perplexed in attempting to comprehend the organization of the minutest Infusoria,[1]
- ↑ Ehrenberg has ascertained that the Infusoria, which have heretofore been considered as scarcely organized, have an internal structure resembling that of the higher animals. He has discovered in them muscles, intestines,
teeth, different kinds of glands, eyes, nerves, and male and female organs of reproduction. He finds that some are born alive, others produced by eggs, and some multiplied by spontaneous divisions of their bodies into two or more distinct animals. Their powers of reproduction are so great, that from one individual (Hydatina senta) a million were produced in ten days; on the eleventh day four millions, and on the twelfth sixteen millions. The most astonishing result of his observations is, that the size of the smallest coloured spots on the body of Monas Termo, (the diameter of which is only of a line) is of a line, and that the thickness of the skin of the stomach may be calculated at from to of a line. This skin must also have vessels of a still smaller size, the dimensions of which are too minute to be ascertained. Abhandlungen der Academie der Wissenschaften zu Berlin, 1831.
Ehrenberg has described and figured more than 500 species of these Animalcules; many of them are limited to a certain number of vegetable infusions; a few are found in almost every infusion. Many vegetables produce several species, some of which are propagated more readily than others in each particular infusion. The familiar case of the rapid appearance and propagation of animalcules in pepper water will suffice to illustrate the rest.
In the London and Edin. Phil. Mag. Aug. 1, 1836, p. 158, there is an extract of a letter sent by M. Alexander Brongniart from Berlin to the Royal Academy of Sciences of Paris, announcing that Ehrenberg has also discovered the silicified remains of Infusoria in the stone called Tripoli (Polie-schiefer of Werner,) a substance which has been supposed to be formed from sediments of fine volcanic ashes in quiet waters. These petrified Infusoria from a large proportion of the substance of this kind of stone from four different localities, on which Ehrenberg has made his observations; they were probably living in the.waters, at the time when they became charged with the volcanic dust, in which the Tripoli originated. It is added in this notice that the slimy Iron ore of certain marshes is loaded with Infusoria, of the genus Gallionella.—L'Institut, No. 166.
These most curious observations throw important light on the obscure and long-disputed question of equivocal generation; the well-known fact that animalcules of definite characters appear in infusions of vegetable and animal matter, even when prepared with distilled water, receives a
