D 



taneous generation, was rendered, as he says, extremely 

 improbable and unnecessary. Subsequently, in various 

 extensive journeys, accomplished under royal patronage, 

 one of which, into Africa, was protracted into a residence 

 of six years, he obtained opportunities of comparing the 

 infusorial forms, found in dilTerent regions of the "lobe, and 

 in 1S30. he communicated his observations to the Berlin 

 Academy, Continuing tliese researches, in which he had 

 become deeply interested, he discovered that the silicious 

 remains of one class of these objects, the Bacillarice, enter 

 into the composition of bog iron ore, are imbedded in ilints, 

 and constitute large strata of the earth's surface. 



The result of all his observations on this subject, lie has 

 given in a series of 30 propositions, a few of which, on 

 account of their importance, are here presented. 



1. All the Infusoria are organized, the greater part, 

 probably all, are highly organized animals. 



2. The Infusoria form two natural classes of animals 

 according to their structure, and may thus be scientitically 

 classed, and adniit no union of their forms with larger 

 animals in corresponding species or families, however 

 similar they may be in appearance. 



3. The existence of Infusoria in four divisions of the 

 globe, and also in the sea, is established, and partictdar 

 species are similar in the most distant regions. 



4. Since a cubic inch of earth often contains more than 

 forty one thousand millions of single animals, the Infusoria 

 form the greatest numerical proportion of individual life that 

 is known, they constitute the principal number, perhaps the 

 principal mass, of living animal organisms on the earth. 



These labop of Professor Ehrenberg have led, as he 

 informs us, to the establishment of two great principles, viz: 

 That there is an animal organization, which does not 

 proceed by gradation, but is perfect in all its principal parts ; 

 and next, that there is a great and direct influence of the 

 world of microscopic forms on unorganized nature. The 



