LAW OF VARIATION. 33 



CHAPTEE III. 



The Law of Variation. 



We come now to consider another law, by which 

 that of similarity is greatly modified, to wit, the law of 

 variation or divergence. All organic beings, whether 

 plants or animals, possess a certain flexibility or pliancy 

 of organization, rendering them capable of change to a 

 greater or less extent. When in a state of nature vari- 

 ations are comparatively slow and infrequent, but when 

 in a state of domestication they occur much oftener and 

 to a much greater extent. The greater variability in 

 the latter case is doubtless owing, in some measure, to 

 our domestic productions being reared under conditions 

 of life not so uniform, and different from, those to which 

 the parent species was exposed in a state of nature. 



Flexibility, of organization in connexion with climate, 

 is seen in a remarkable degree in Indian corn. The 

 small Canada variety, growing only three feet high and 

 ripening in seventy to ninety days when carried south- 

 ward, gradually enlarges in the whole plant until it 

 may be grown twelve feet high and upwards, and re- 

 quires one hundred and fifty days to ripen its seed. A 



