108 THEORY OP THE EARTH. 



character, relative to the class, order, genus, and 

 species of the animal to which it belonged ; inso- 

 much, that, when we find merely the extremity of a 

 well-preserved bone, we are able, by careful ex- 

 amination, assisted by analogy and exact compari- 

 son, to determine the species to which it once be- 

 longed, as certainly as if we had the entire animal 

 before us. Before venturing to put entire confi- 

 dence in this method of investigation, in regard to 

 fossil bones, I have very frequently tried it with 

 portions of bones belonging to well-known animals, 

 and always with such complete success, that I now 

 entertain no doubt with regard to the results which 

 it affords. I must acknowledge that I enjoy every 

 kind of advantage for such investigations that 

 could possibly be of use, by my fortunate situation 

 in the Museum of Natural History ; and, by assi- 

 duous researches for nearly fifteen years, I have 

 collected skeletons of all the genera and sub-gene- 

 ra of quadrupeds, with those of many species in 

 some of the genera, and even of several varieties 

 of some species. With these aids, I have found it 

 easy to multiply comparisons, and to verify, in 

 every point of view, the application of the forego- 

 ing rules. 



We cannot, in the present Essay, enter into a 

 more lengthened detail of this method, and must 

 refer for its entire explanation to the large work 

 on Comparative Anatomy, which we propose to 

 publish very soon, and in which all its laws will 



