MAKSUPIALIA 299 



u 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 gradation 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 hi 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 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 shows 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, resulting from 



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

 suffisantc ; mais comme nous ne la connoissons pas, nous devons supplier an 

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



f " En effet, quand on tonne un tableau de ces rapports, on y rem ar que noii- 

 Beulement une Constance specifiqne, si Ton pent s"exprimer ainsi, entre telle 

 forme de tel organe, et telle autre forme d'un organ e 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 raisonne- 

 111 • 11 1 effectif, leur influence mutuelle." (Tom. eit., p. 185.) 



