1^04 NATURAL HISTORY. 



proved, by late discoveries, that many formations of rock 

 owe their origin to the Infusoria. For instance, chalk 

 cliffs are supposed to have arisen from a combination of 

 the calcareous scales or shells of the animalcule, belong- 

 ing to the antediluvian world. This class feed not only 

 on all corrupt substances, but also seize and devour each 

 other. Space can not be afforded for a general review 

 of the species. We will, however, mention a few. 



The Smallest Point (monas termo) a thousandth part 

 of a line (tenth of an inch) long, and, a mere point, is a 

 simple globule, without tail or eyes ; nevertheless, it 

 swims about rapidly by means of its mouth. A single 

 drop of water is said to contain five thousand millions. 



The Globe (volvox globator), being about the third of 

 a line in size, can be seen by the naked eye. It is trans- 

 parent, studded with more minute globes of green. If 

 viewed under a microscope, these minute creatures can 

 be seen revolving with great rapidity on their own axis. 



The Wheel Animalcule (virdicella senta) is one-sixth 

 of a line long ; almost globular ; as it moves emits a 

 phosphorescent luster. 



The Vinegar Eel (vibrio asceti) is hardly a line in 

 length, and has a thread-like body ; found in great num- 

 bers in vinegar, so that many thousands are swallowed in 

 taking a spoonful of this fluid. Are never found in bad 

 vinegar. 



