28o 



Vitality of Seeds. 



[AUG., 



whilst in Michigan, where the rainfall was only 285 inches 

 and the mean temperature 49 degrees F. the loss of vitality 

 only amounted to 2\ per cent. Figures tending to support 

 this conclusion are also given for other places ; though the 

 comparisons were found to be somewhat indefinite. If the 

 rainfall had been equally distributed throughout the year a 

 definite ratio could, it is thought, have been established, but in 

 the majority of the places where the experiments were made 

 there were alternating wet and dry seasons, which made the 

 comparisons very difficult and unsatisfactory, The evidence 

 obtained, however, seemed to show quite clearly that seeds retain 

 their vitality much better in places having a small rainfall. It 

 was also found experimentally that most seeds if kept in a dry 

 atmosphere were not injured by prolonged exposure to tem- 

 peratures below 98J degrees F., but if the temperature was 

 increased above that point the vitality was seriously reduced, 

 and long exposures to a temperature from 102 degrees to 104 

 degrees F. were found to cause premature death ; if the seeds 

 were kept in a moist atmosphere, a temperature as high as 86 

 degrees F. was found to cause much injury in a comparatively 

 short period. In this connection it must be remembered that 

 grain, first stored in stacks and afterwards used for seed, may have 

 been exposed to a much higher temperature than the surrounding 

 air when in the interior of the rick. 



The curing of seeds is of the utmost importance, and great 

 care should be taken to prevent excessive heating, otherwise the 

 vitality will be greatly lowered. When seeds come to be stored 

 the main factor to be considered is dryness, and they should be 

 put in well ventilated rooms kept dry by artificial heat. This 

 method of treatment requires that the seeds be well cured and 

 well dried before storing, but in no case must the temperature 

 of the storehouse be increased unless the seed is amply venti- 

 lated, so that the moisture from the seed can be carried off readily 

 by the currents of air. If this precaution is not taken the 

 increased humidity of the air confined between the seeds will 

 cause a marked injury. For this reason seeds kept at low 

 temperature during the winter deteriorate in the warm weather 

 of spring, especially if they contain much moisture. 



The bulletin, which contains an account of the various 



