26 



fHEORY OF THE EARTH. 



fragments formerly belonged, and then of compar- 

 ing them with those animals which still live on the 

 surface of the earth; an art which is almost unknown, 

 and which presupposes, what had scarcely been 

 obtairie-d jbfcfore, an acquaintance with those laws 

 which regulate the coexistence of the forms by 

 wh'i'cih; th>e Different parts of organized beings are 

 distinguished. I had next to prepare myself for 

 these inquiries by others of a far more extensive 

 kind, respecting the animals which still exist. 

 Nothing, except an almost complete review of 

 creation in its present state, could give a character 

 of demonstration to the results of my investiga- 

 tion in its ancient state ; but that review has afford- 

 ed me, at the same time, a great body of rules 

 and affinities which are no less satisfactorily de- 

 monstrated; and the whole animal kingdom has 

 been subjected to new laws in consequence of this 

 Essay on a small part of the theory of the earth.* 



The importance of the truths which have been 

 developed in the progress of my labours, has con- 

 tributed equally with the novelty of my principal 

 results to sustain and encourage my efforts. May 

 it have a similar effect on the mind of the reader, 

 and induce him to follow me patiently through the 

 difficult paths in which I am under the necessity of 

 leading him ! 



* This will be seen more at large in the extensive work upon Com- 

 parative Anatomy, in which I have been employed for more than 

 twenty-five years, and which I intend soon to prepare for publication. 



