46 MARKET GARDENING. 



vested ; third, upon the greater or lesser moisture of the 

 air in which they are stored ; and, fourth, upon proper 

 ventilation of the bags or packages. On the southern 

 seaboard, and in the Gulf States, where the air is very 

 moist, at times, perfectly fresh seeds frequently lose 

 their vitality by the end of the first year, while far inland 

 and in dry sections of the country, and especially in 

 high latitudes, they may, with few exceptions, be safely 

 used the second season. The primary cause, however, 

 of difference in period of duration of the growing powers 

 of seed, depends principally upon difference in their 

 chemical composition. 



All seed may be divided into two classes, those in 

 which oil predominates, those in which starch predom- 

 inates ; and it is the first which most rapidly change by 

 decomposition, the starchy seeds, with the exception of 

 corn, being least subject to chemical change and most 

 tenacious of life. 



Testing Seeds. When it is desired to determine 

 the vitality of a seed, the test should always be made by 

 counting out lots of one hundred seeds, just as they are, 

 good, bad and indifferent ; better still, to take several 

 lots of one hundred seeds of each variety, that one lot 

 may serve to prove the other. In all such cases the 

 experimenter should have a sample of another lot of the 

 same variety of seed from a distinct source, of which he 

 already knows the true vitality, this to serve as a proof 

 or standard in estimating the accuracy of the test. The 

 test of vitality may be made in a number of ways, the 

 most reliable, of course, being in earth ; sandy loam in 

 broad pots or trays, well placed as respects heat and 

 moisture, or, better still, the seed sown in earth on the 

 benches of a greenhouse. 



A second method of testing geeds is by germinating 

 them in flannel cloths suspended over water trays, from 

 which the flannel becomes damp by capillary attraction. 



