Conditions of Storing 131 



spoiled in a short time by improper conditions of 

 storing. 



The failure of seeds from conditions of preserva- 

 tion is illustrated in a method employed by Sturtevant. 

 The following table represents germinations of various 

 varieties of corn, selected from a large series of 

 experiments : 



No. of No. of Percent 



Age of seed trials seeds tried germination 



% year 17 1,075 100 



2 years 37 3,005 100 



3 years 7 725 100 



5 years 1 93 100 



Under proper conditions, therefore, corn preserves 

 its vitality perfectly for five years. The next table 

 exhibits the germinations of the entire series from 

 which the former examples were selected: 



Age of seed 



1 year . 



2 years 



3 years 



4 years 



5 years 



The differences between the minimum percentages 

 and 100 per cent must be due to conditions of preser- 

 vation. The average percentage of germination in each 

 case represents an exact measure of loss. This loss 

 amounts in the total average to 18.8 per cent. 



5. Mechanical and insect injuries usually lessen the 

 germinative vitality of seeds. The threshing process 



