EFFECT OF MOISTURE AND TEMPERATURE. 29 



of the first series of tests show a slight increase in favor of the seeds 

 kept in the bottles, though the increase is not so well marked and is 

 less uniform than in those of the second series. 



Aside from the final germination there is still another factor that 

 must be taken into consideration as bearing evidence of the advantage 

 of keeping seeds at low temperatures, provided that they are kept dry. 

 All of the samples that were stored in the ice house in bottles showed 

 a marked acceleration in germination. It is quite evident that the res- 

 pi ratory activities and accompanying chemical transformations were 

 much reduced by the reduction in temperature, and the vital energy was 

 thus conserved; but when the conditions were favorable for germination 

 the greater amount of reserve energy in these seeds gave rise to a more 

 vigorous activity within the cells and a corresponding* acceleration in 

 germination. 



Numerous other experiments showing the effect of moisture on the 

 vitality of seeds were made. In contrast to those just given, the 

 injurious action of moisture at higher temperatures, yet temperatures 

 well within the limits of those ordinarily met with in the handling of 

 seeds, will be next considered. 



EFFECT OF MOISTURE ON VITALITY AT HIGHER TEMPERATURES. 



This set of experiments was undertaken particularly to furnish con- 

 ditions somewhat similar to those existing in the States bordering on 

 the Gulf of Mexico, or, in fact, all places having a relatively high 

 degree of humidity and a temperature ranging from 30 to 37 C. 

 (86 to 98.6 F.) during the summer months. In order to secure the 

 desired degrees of temperature two incubators were utilized, one being 

 maintained at a temperature varying from 30 to 32 C., the other 

 from 36 to 37 C. The thermo-regulators were so adjusted as to 

 admit of a possible variation of nearly two degrees in each case. 



Beans, cabbage, carrot, lettuce, and onion were used for these tests. 

 In each of the incubators the seeds were subjected to four different 

 methods of treatment: 1. In a moist atmosphere, in free communica- 

 tion with the outside air. 2. In a moist atmosphere, but not in con- 

 tact with fresh air, the seeds being in sealed bottles of 250 cc. capacity. 



3. In a dry atmosphere, in free communication with the outside air. 



4. Air-dried seeds in sealed bottles. 



In order to obtain the conditions requisite for the first method of 

 treatment, an apparatus was used as shown in figure 1. The seeds were 

 put up in small packages and then placed in a 250 cc. bottle. The bottle 

 containing the packages of seeds was placed withki a specimen jar 

 which was partially filled with water. This jar was then closed with 

 a large cork stopper which carried two glass tubes, each of 1 cm. bore. 

 These tubes extended 25 cm. above the top of the jar and out through 



