102 HISTORY OF THE WOEKS OF CUVIER. 



principle wLicli governs or co-ordinates tlie movements of locomotion ; tlie 

 •medulla ohhngafa, seat of the principle which controls the movements of respira- 

 tion. Now, in the bird, the part of the brain which, relatively to the brain of 

 other vertebrate animals, predominates, is precisely that Avhich governs or co-ordi- 

 nates the movements of locomotion ; it is the ccrebcUmn. All the parts, all the 

 functions, all the modifications of the parts and of the functions, are therefore 

 formed each for the others, and all for a given purpose. 



We have seen this as regards respiration, as regards the act of flying, &c. It 

 is easily shown as regards digestion. The system of an animal is, in effect, by 

 no means an arbitrary thing. It is not by hazard that incisive teeth coincide 

 with a single stomach ; flat and dull teeth with a multiple stomach ; flat teetli, 

 a multiple stomach, with a herbivorous diet, &c. A single one of those things, 

 necessarily supposes all the others, or excludes them all. An animal with long 

 intestines, a multiple stomach, flat teeth, is necessarily herbivorous. A carniv- 

 orous animal has, necessarily, incisive teeth, a single stomach, short intestines ; 

 it has, moreover, and just as necessarily, divided and movable digits, to seize its 

 prey ; and, even in the T)rain, it has a peculiar instinct which impels it to nour- 

 ish itself on flesh. Never will such an instinct nor an incisive tooth co-exist in 

 the same animal, with a foot enveloped in horn, for these things are incompatible 

 and contradict one another; the animal in which they presented themselves 

 together could not subsist. The laws of organic correlations, properly viewed, 

 are the very conditions of the existence of beings. 



After the law of organic correlations, comes, as we have said, the law of the 

 suhordination of organs. A recognized subordination everywhere subjects cer- 

 tain organs to others : the ore-ans of locomotion to those of dio'estion : the orcfans 

 of circulation to those of respiration ; all functions and all organs to the nervous 

 system. Circulation, for instance, does or does not exist, according as respira- 

 tion is conducted in such or such a manner. All animals with a circumscribed 

 respiration (the vertebrata, the mollusks, the Crustacea, &c.,) have, necessarily, 

 a circulation ; for it is necessarj^ that the blood should arrive in the organ which 

 receives the air, and it is the circulation which carries it thither. The insects, 

 in place of a circumscribed respiration, have a general respiration, executed by 

 means of trachea?, which carry the air everywhere ; in their case, there was no 

 need of eirculation, and there is none. 



The same subordination connects the organs of locomotion or oiprehension with 

 the digestion. And such is the force of this subordination that one of these organs 

 seems incapable of making any progress without manifesting a similar progress 

 in the other. Thus, for example, the ruminant animals have, in general, neither 

 canine nor incisive teeth in the upper jaw, and there are but five bones to their 

 tarsus ; the camel has canines, and even two or four incisives in the upper jaw, 

 and already we observe an additional bone in the tarsus, because the scaphoid is 

 here not consolidated with the cuboid ; further, the common ruminants have, for 

 the whole fbida, only a small bone articulated at the base of the tibia, and the 

 chevrotain or vioschus, which has canines well developed, has a distinct and 

 complete fibula. Sec. 



v. — COMPARATIVE OSTEOLOGY. 



This branch of science, sprung from the labors of Daubenton,of Camper, of 

 Pallas, has become, in the hands of M. Cuvier, a new instrument ; it was by 

 comparative osteology that he reconstructed the lost species of ancient worlds ; 

 and it is well worthy of remark thak in this long and laborious series of researches 

 and eftbrts none of these learned men ever diverged from the domain of positive 

 facts. Such, effectively, is the empire of these facts over the human mind that, 

 except in their default, it scarcely ever throws itself into the domain of con- 

 jecture and hypothesis. In almost every line it is only when the facts are not 



