336 PALEONTOLOGY. 



" However," continues Cuvier, " since these relations are 

 constant, they must have a sufficing cause ; but as we are 

 ignorant of it, we must supply the want of the theory by means 

 of observation .* This, if adequately pursued, will serve to 

 establish empirical laws almost as sure in their application as 

 rational ones." " That there are secret reasons for all these 

 relations, observation may convince us independently of 

 general philosophy." " The constancy between such a form of 

 such organ, and such another form of another organ, is not 

 merely specific, but one of class, with a corresponding grada- 

 tion in the development of the two organs."")" 



" For example, the dentary system of non-ruminant Ungu- 

 lates is generally more perfect than that of the Bisulcates ; 

 inasmuch as the former have almost always both incisors and 

 canines in the upper as well as the lower jaw ; the structure 

 of their feet is in general more complex, inasmuch as they have 

 more digits, or hoofs less completely enveloping the phalanges, 

 or more bones distinct in the metacarpus and metatarsus, or 

 more numerous tarsal bones ; or they have a more distinct 

 and better developed fibula; or a concomitance of all these 

 modifications. It is impossible to assign a reason for these 

 relations ; but, in proof that it is not an affair of chance, we 

 find that whenever a bisulcate animal shews in its dentition 

 any tendency to approach the non-ruminant Ungulates, it also 

 manifests a similar tendency in the conformation of its feet. 

 Thus the camels, which have canines and two or four incisors 

 in the upper jaw, have an additional bone in the tarsus, result- 



* " Puisque ces rapports sont constants, il faut bien qu'ils aient une cause 

 suffisante ; mais comme nous ne la connoissons pas, nous devons suppleer au 

 defaut de la theorie par le moyen de l'observation." (Tom. cit., p. 184.) 



f " En effet, quand on forme un tableau de ces rapports, on y remarque non- 

 seulement une Constance specifique, si Ton peut s'exprimer ainsi, entre telle 

 forme de tel organe, et telle autre forme d'un organe different ; mais Ton apercoit 

 aussi une Constance de classe et une gradation correspondante dans le developpe- 

 ment de ces deux organes, qui montrent, presque aussi bien qu'un raisonnement 

 effectif, leur influence mutuelle." (Tom. cit., p. 185.) 



