RELATIONS. l70 



II. The relation of the kidneys to the bladder, and of the 

 dreters to both, that is, of the secreting organ to the vessel 

 receiving the secreted liquor, and tlie pipe laid from one to 

 the other for the purpose of conveying it from one to the 

 other, is as manifest as it is among the different vessels em- 

 ployed in a distillery, or in the communications between 

 them. The animal structure, in this case, being simple, 

 and the parts easily separated, it forms an instance of corre- 

 lation which may be presented by dissection to every eye, or 

 which indeed without dissection is capable of being appre- 

 hended by every understanding. This correlation of instru- 

 ments to one another fixes intention somewhere ; especially 

 when every other solution is negatived by the conformation. 

 If the bladder had been merely an expansion of the ureter, 

 produced by retention of the fluid, there ought to have been 

 a bladder for each ureter. One receptacle fed by two pipes 

 issuing from different sides of the body, yet from both con- 

 veying the same fluid, is not to be accounted for by any such 

 supposition as this. 



III. Relation of parts to one another accompanies us 

 throughout the whole animal economy. Can any relation 

 be more simple, yet more convincing than this, that the eyes 

 are so placed as to look in the direction iai which the legs 

 move and the hands work ? It might have happened very 

 difierently if it had been left to chance. There were at least 

 three quarters of the compass out of four to have erred in. 

 Any considerable alteration in the position of the eye or the 

 figure of the joints would have disturbed the line and de- 

 stroyed the alliance between the sense and the limbs. 



IV. But relation, perhaps, is never so striking as when 

 it subsists, not between different parts of the same thing, but 

 between difierent things. The relation between a lock and 

 a key is more obvious than it is between different parts ol 

 the lock. A bow was designed for an arrow, and an arrow 

 for a bow ; and the design is more evident for their being 

 separate implem.ents. 



