2 BOOK OF NATURE LAID OPEN. 



about which we mean not here to treat. One ob- 

 servation, however, upon a general view of the 

 whole, as it cannot fail in time to present itself to 

 every person who engages in this study, may here 

 be introduced: it is, that however easy it may seem, 

 at the first glance, to discriminate the three classes 

 of objects from each other, yet every class of natural 

 objects will be found to approach so nearly in the 

 extreme of other classes, that it is a matter of diffi- 

 culty to say with precision where the one ends, and 

 the other begins. The whole are so closely con- 

 nected, like the links of a chain, that there is no 

 possibility of finding a disjunction in any part. 

 Among animated beings, bats are the connecting 

 link between beasts and birds: the numerous class 

 of amphibia conjoin beasts and fishes; and lizards 

 unite them with reptiles The humming-bird ap- 

 proaches the nature of insects, and the flying-fish 

 that of birds The polypus, the sea anemony, and 

 the sea pen, though of animal origin, have more the 

 habits of vegetables than of animals; while the 

 fly-trap, the sensitive plant, and some other vegeta- 

 ble productions, by their spontaneous movements, 

 or extreme sensibility, seem to participate more of 

 animal origin. Corals and corallines, from the dif- 

 ferent forms they assume, may be more easily mis- 

 taken for mineral or vegetable than animal produc- 

 tions, to which class they are now referred, by the 

 unanimous decision of naturalists. The trufle, though 

 a vegetable, assumes rather the appearance of a 

 mineral; and there is reason to believe that the 



