RELATIONS. 157 



V. The teats of animals, which give suck, bear a re- 

 lation to the mouth of the suckling progeny ; particularly 

 to the lips and tongue. Here also, as before, is a corres- 

 pondency of parts ; which parts subsist in different indi- 

 viduals. 



These are general relations, or the relations of parts 

 which are found, either in all animals, or in large classes 

 and descriptions of animals. Particular relations, or the 

 relations which subsist between the particular configura- 

 tion of one or more parts of certain species of animals, 

 and the particular configuration of one or more other parts 

 of the same animal, (which is the sort of relation, that is, 

 perhaps, most striking,) are such as the following: 



I. In ihesivan; the web-foot, the spoon-bill, the long 

 neck, the thick down, the graminivorous stomach, bear all 

 a relation to one another, inasmuch as they all concur in 

 one design, that of supplying the occasions of an aquatic 

 fowl, floating upon the surface of shallow pools of water, 

 and seeking its food at the bottom. Begin with any one 

 of these particularities of structure, and observe how the 

 rest follow it. The web-foot qualifies the bird for swimming ; 

 the spoon bill enables it to graze. But how is an animal, 

 floating upon the surface of pools of water, to graze at the 

 bottom, except by the mediation of a long neck ? A long 

 neck accordingly is given to it. Again, a warm blooded ani- 

 mal, which was to pass its life upon water, required a de- 

 fence against the coldness of that element. Such a defence 

 is furnished to the swan, in the muffin which its body is 

 wrapped. But all this outward apparatus would have been 

 in vain, if the intestinal system had not been suited to the 

 digestion of vegetable substances. I say suited to the di- 

 gestion of vegetable substances; for it is well known, that 

 there are two intestinal systems found in birds, one with a 

 membranous stomach and a gastric juice, capable of dissolv- 

 ing animal substances alone ; the other with a crop and 

 gizzard, calculated for the moistening, brusing, and after« 

 terwards digesting, of vegetable aliment. 



Or set off with any other distinctive part in the body 

 of the swan; for instance, with the long neck. The long 

 neckjwithoutthe web-foot, would have been an encumbrance 

 to the bird ; yet there is no necessary connexion between 

 a long neck and a web-foot. In fact they do not usually 

 go together. How happens it, therefore, that they meet 

 only when a particular design demands the aid of both I 



