Multiplication of Extremes 747 



Putting this discussion in other terms, we find 

 every individual and every organ in the adult 

 state corresponding with a single ordinate of 

 the curve. The curve indicates the range of 

 possibilities, the ordinate shows the choice that 

 has been made. Now it is clear at once that 

 this choice has not been made suddenly but 

 gradually. Halfway of the development, the 

 choice is halfway determined, but the other half 

 is still undefined. The first half is the same for 

 all the organs of the plant, and is therefore 

 termed individual; the second differs in the 

 separate members, and consequently is known as 

 partial. Which of the two halves is the greater 

 and which the lesser, of course depends on the 

 cases considered. 



Finally we may describe a single example, the 

 length of the capsules of the evening-primrose. 

 This is highly variable, the longest reaching 

 more than twice the length of the smallest. 

 Many capsules are borne on the same spike, 

 and they are easih^ seen to be of unequal size. 

 They vary according to their position, the 

 size diminishing in the main from the base up- 

 wards, especially on the higher parts. Like- 

 wise the fruits of weaker lateral branches are 

 smaller. Curves are easily made by measuring 

 a few hundred capsules from corresponding 

 parts of different plants, or even by limiting tlie 



