OP PLANTS AND ANIMALS. 179 



built cities and founded empires. We have arrived now at 

 the historical era. From the written accounts which have 

 been transmitted to us, it is clear that the long reign of 

 instinct is giving place to that of reason, and that the pre- 

 sent period of the world's history is characterized by its 

 slow development. 



The occurrence of human skeletons, and of coins and 

 works of art, in modern fluviatile and marine deposits ; the 

 preservation of the bones of the existing species of ani- 

 mals, and of the leaves and branches of plants now grow- 

 ing on the earth's surface, in the various geological forma- 

 tions now in progress, shows the immutability of nature, 

 and proves that the same enduring monuments of the pre- 

 sent state of things will be transmitted to future ages. 

 When the beds now forming in the existing seas shall be 

 elevated above the waters and covered with woods and 

 forests; when the deltas of our rivers shall be converted 

 into fertile tracts, and become the sites of towns and cities ; 

 in excavating the earth thus newly created, there is little 

 doubt that the then existing races of men will discover the 

 same indelible records of the physical history of our times, 

 as we have now of that of former ages. 



The Linnsean maxim, "Natures mirandaest maxime in 

 minimis," nature is chiefly to be admired in the least 

 things, is as yet only partially appreciated by a few distin- 

 guished minds, although it should never be lost sight of 

 in the investigation of vital phenomena. If it be philoso- 

 phical to pursue researches in the physical sciences by ex- 

 periments and observations on the properties of inorganic 

 matter ; it would seem to be equally in accordance with the 

 principles of science, in the study of organic nature, to 

 adhere as closely as possible to the plan of nature, and 

 trace her operations in the simpler forms of life before we 



