210 Bibliography. 



" 2. The results already obtained by direct examinations have prov- 

 ed, that in all zones of the surface of the earth, in all climates, in low 

 situations, and the bottom of the ocean, as well as on high mountains 

 at the elevation of about nine thousand feet, (Niglherri, Mexico,) and 

 even in the smallest particles of humus, microscopic life has not merely 

 an existence, but is in exuberant abundance. 



" 3. The European microscopic organisms have been shown to be 

 so related to those of other parts of the earth, that new orders, classes, 

 and families, are no where found, but the forms all belong to the often 

 siliceous, never calcareous shelled Polygastric infusoria, and to the 

 never siliceous but generally calcareous shelled Polythalamia, which 

 are not infusoria. 



"4. Besides these independent microscopic forms of life, there also 

 are found in soil and in calcareous strata all over the earth, astonishing 

 numbers of small undecomposed regular parts of larger organisms, 

 which are either siliceous or calcareous, and both of vegetable and ani- 

 mal origin which every where present the closest resemblance in char- 

 acters, however different may be the Flora or Fauna of the localities. 



" 5. In place of orders, classes, or families, peculiar to different parts 

 of the world, there occur peculiar local genera, which however are 

 no where numerous, while on the contrary there are very numerous 

 peculiar species of widely distributed genera. 



" 6. Certain geographical latitudes have their characteristic forms of 

 minute animal life. Thus the proportionally large and slender serrated 

 species of Eunotia — E. tetraodon, pentodon, diadema, serrulata, &lc. — 

 have hitherto been found only in Sweden, Finland, and in North Amer- 

 ica, from New York to Labrador. Similar species of the broad and 

 small, many-toothed species of Himantidium and Eunotia only occur 

 on the south coast of Asia, at Senegal in Africa, and in Cayenne in 

 South America. The genus Tetragramma is found only in Libya and 

 in the Ladrone isles, and the same species occurs at both places. 



" 7. There is distributed over all parts of the earth a considerable 

 number of perfectly identical forms, among which are {Navicula), Pin- 

 nularia viridis, Himantidium arcus, and Eunotia amphioxys. These 

 most common forms appear to be the most important in their relations 

 to the economy of nature. 



" 8. The so-called inorganic constituents of the body and shells of ani- 

 malcules are chiefly carbon, silica, lime, and iron, with traces of alu- 

 mina and manganese ; magnesia and other substances are probably only 

 present as mechanical mixtures. 



" 9. The quantity of iron in the minutest organisms is sometimes 

 surprisingly great. It is never united with the lime, but only with the 

 silica, appearing to be rather mechanically than chemically combined, 



