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, however, were old seed, which 

 had apparently lost their power of germinating, and the 

 stimulating eftect induced by soil sterilization evidently had 

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

 when seeds have once lost their germinating power, or, in 

 other words, are dead, this process will revive them. The 

 percentage gained in some instances is (|uite marked, while 

 in others it is insignificant. The average obtained from this 

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

 capacity prevailing here in many instances, the percentage 

 gained is only indicative, since it would be necessary to 

 employ a larger num))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 with lettuce, cucumber, 

 melon seed, etc., in the greenhouse, where seed was used 

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

 mination is also marked^ a feature which has been fre(|uently 

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

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

 15 to 34, inclusive, was 1()9 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, 

 previously 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 

 dilferent species of seeds is not known. Experiments are 

 now being made along different lines which may throw some 

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

 ing seed in sterilized soil, both from a physiological and 

 pathological point of vicw% is important enough to warrant 

 in many instances its practice. 



