86 VARIATION 



It is sufficient for the present purpose to note that there was 

 a difference of 5.62 per cent (13.87-8.25) in the protein content 

 of the highest and the lowest ears of the 163 analyzed ; of 3.51 

 per cent (12.54-9.03) in the seed planted ; and of 0.55 per cent 

 (11.18-10.55) in the crop harvested the first year. 



It is not the intent to pursue this subject further at this 

 point. It will be fully discussed under heredity and under plant 

 breeding, but enough has been quoted to show that these func- 

 tional differences are both distinctive and hereditary, and that in 

 it all the ear is the unit to such an extent that it is entirely prac- 

 ticable to permanently influence functional differences by selec- 

 tion. Indeed this has been done already to such an extent that 

 corn has been produced with a higher protein content than wheat. 



Variation in sugar production. Sugars of various kinds are 

 produced by many plant and animal activities. Certain plants 

 excel in this particular function, and among these wide differ- 

 ences have been found, leading to marked and permanent in- 

 crease in the amount of sugar produced. The beet, for example, 

 though originally producing but from 4 to 6 per cent of sugar, 

 has been so improved and its sugar-producing activities have 

 been so increased as to yield specimens containing as high as 

 25 per cent of sugar and whole crops averaging 14 per cent. 



Cane is also variable, and every one familiar with the maple 

 knows that certain trees will yield a large amount of exceed- 

 ingly sweet sap, while others yield but little, which little may 

 be either sweet or tasteless, indeed, even bitter. 



Variation in speed, scent, and organic activities generally. 

 One horse is faster or more enduring than another, not so 

 much from conformation as from inherent activity and power 

 of endurance. Some dogs are especially keen in scent, others 

 are defective, and the hearing instinct is much better developed 

 in some individuals (dogs, cats, horses, cattle, birds, etc.) than 

 in others. 1 



Mental qualities, personal tastes, and intellectual ability in 

 general are conditioned not upon conformation but upon the 



1 It is more than likely that some of these differences are connected with the 

 degree of development of certain portions of the nervous system. They are 

 none the less functional, however. 



