O F T H E F OE T U S, 307 



Hence we may conclude, that, if there is any 

 defeat, or redundance, in the matter deftined for 

 the formation of the double parts, as the forces 

 are equal on each fide, this defed or excefs 

 muft take place both in the right and left fides. 

 If, for example, from a defedt of matter, a man 

 has but two fingers in the right hand, in place 

 of five, the fame defe(ft will appear in tlie left ; 

 if, from an excefs of matter, there be fix 

 fingers in the right hand, he will have the fame 

 number in the left; or, if the matter be vitiated^ 

 and produces a change in the parts of one fide, 

 the fame change will appear in the other. Of 

 this fadt we have daily proofs : The parts of 

 monfters are always deranged in a certain order 

 and proportion. Hence Nature, even in her er- 

 rors, uniformly commito the leaft of pofTible 

 miftakes. 



This harmony in the pofition of the double 

 parts of animals, is likewife apparent in vege- 

 tables. The branches pufli out final! ramifi- 

 cations on each fide ; the fmall nerves in the 

 leaves are equally difpofed with regard to the 

 principal nerve; and, if the fymmetry appear^ 

 to be lefs cx^Ct in vegetables than in animals, 

 this proceeds only from its being mote various^ 

 and bccaufe its limits arc more extenfive, and 

 lefs prccile. But the fame order is eafily rccog- 

 nifable; and the fingle and eflential parts aie 

 i)crfcdly diftinct from thofc which are double ; 



U 2 zud 



