36 MEMOIR OF LAMARCK. 



bitudes. It is susceptible of demonstration, that if 

 species had an absolute constancy, there would be 

 no varieties, but naturalists cannot help acknowledg- 

 ing that such exist*. 



Whatever changes circumstances may have pro- 

 duced in individuals, are all preserved by genera- 

 tion, and transmitted to new individuals emanating 

 from those which have undergone these changes. 

 Unless this were the case, Nature could never have 

 introduced the diversity among animals which we 

 now witness, nor a progression in the composition 

 of their organs and faculties t. 



Such is Lamarck's theory of life, and manner of 

 accounting for the innumerable variety of forms in 

 which living nature now appears. If his principles 

 were once admitted, they would not only produce 

 the effects he ascribes to them, but it would be 

 a matter of surprise that natural productions are 

 not infinitely more diversified than they really are, 

 for nothing more is necessary than time and cir- 

 cumstances for any one animal form to be trans- 

 formed into any other, — for a monad or a polypus 

 to become indifferently a frog, an eagle, an elephant, 

 or a man. But the two suppositions on Avhich they 

 rest, viz. that it is the seminal vapour which orga- 

 nizes the embryo, and that efforts and desires en- 

 gender organs, are both so entirely arbitrary, and 

 the latter so obviously fallacious, that very few have 

 ever thought it worth while to attempt a formal 



* Aminaux sans Vertebres, vol. i. p. 197, 198. 

 f lb. p. 199. 



