336 HOW CROPS GROW. 



that those who have raised mummy wheat or mummy 

 peas were deceived either by an admixture of fresh seed 

 with the ancient, or by planting in ordinary soil, which 

 commonly contains a variety of recent seeds that come 

 to light under favorable conditions. 



Dietrich (/?o/. Jahr., 1862-3, p. 11) experimented 

 with seeds of wheat, rye, and a species of Bromus, which 

 were 185 years old. Nearly every means reputed to favor 

 germination was employed, but withoat success. After 

 proper exposure to moisture, the place of the germ was 

 usually found to be occupied by a slimy, putrefying liq- 

 uid. Commonly, among the freshest seeds, when put to 

 the sprouting trial, some will mold or putrefy. 



The fact appears to be that the circumstances under 

 which the seed is kept greatly influence the duration of 

 its vitality. If seeds, when first gathered, be thoroughly 

 dried, and then sealed up in air-tight vessels, there is no 

 evident reason why their vitality should not endure for 

 long periods. Moisture and the microbes that flourish 

 where it is present, not to mention insects, are the agen- 

 cies that usually put a speedy limit to the duration of 

 the germinative power of seeds. 



In agriculture it is a general rule that the newer the 

 seed the better the results of its use. Experiments have 

 proved that the older the seed the more numerous the 

 failures to germinate, and the weaker the plants it pro- 

 duces. 



Londet made trials in 1856-7 with seed-wheat of the 

 years 1856, '55, '54, and '53. The following table exhib- 

 its the results : 



Nuviher of stalks 



Per cent of seeds Length of leaves four days and earsper 



sprouted. c^ter coming up. hundred seeds. 



Seed of 1853 none 



" " 1854 51 0.4 to 0.8 Inches. 269 



" " 1855 73 1.2 " 365 



" " 1866 74 1.6 " 404 



The results of similar experiments made by Haberlandt 

 on various grains are contained in the following table : 



