128 HATCH EXPERIMENT STATION. [Jan. 



ment, this being made in the greenhouse bench soil ; 500 

 seeds Avere sown in unsterilized soil and 500 in sterilized 

 soil. 



The data given in the table show that there occurred a 

 positive gain in germination of the seed sown in sterilized 

 soil. Nos. 20, 29 and 33, hoAvever, Avere old seed, which 

 had apparently lost their poAver of germinating, and the 

 stimulating effect induced by soil sterilization evidently had 

 no effect on them. There is no reason for believing that 

 Avhen seeds have once lost their germinating poAver, or, in 

 other Avords, are dead, this process Avill revive them. The 

 percentage gained in some instances is (juite marked, Avhile 

 in others it is insignificant. The average obtained from this 

 series is 21 per cent. On account of the Ioav germinating 

 capacity prevailing here in many in,stances, the percentage 

 gained is only indicative, since it would be necessary to 

 employ a larger numl)er of seeds to obtain more accurate 

 averages. It should be pointed out, however, that better 

 results than those given in these experiments have been ob- 

 served many times in connection Avith lettuce, cucumber, 

 melon seed, etc., in the greenhouse, Avhere seed Avas used 

 on a much larger scale. The degree of acceleration in ger- 

 mination is also marked, a feature Avhich has been fre(j[uently 

 noticed by us before. The number of seeds germinated dur- 

 ing the first fcAv days of these experiments, including Nos. 

 15 to 34, inclusive, Avas 169 for the sterilized soil and 146 

 for the normal loam, or a gain of 14 per cent, in favor of 

 the sterilized soil. In the former series of experiments, 

 previousl}^ noted, we obtained 25 per cent, of acceleration 

 at the end of four days. There undoubtedly exists a differ- 

 ence in seeds in their response to stimulation in sterilized 

 soils. Tomatoes, for example, respond but little if any to 

 this method of treatment. The cause of this variation in 

 diU'crent species of seeds is not knoAvn. Experiments are 

 noAV being made along dilfcrent lines Avhich may throw some 

 light on this question. The benefit to be derived from soav- 

 ing seed in sterilized soil, both from a physiological and 

 pathological point of vicAV, is important enough to Avarrant 

 in many instances its practice. 



