

VITALITY AND GERMINATION OF SEEDS. 229 



3 weeks, show much less tendency to form root nodules 

 than the roots of normal seedlings do. Thus on the roots 

 of normal seedlings 10 days old a few root nodules were 

 found whereas upon the roots of alcohol seedlings of the 

 same age none were to be seen. On, however, performing 

 further experiments it was found that the numbers of 

 root nodules formed were relatively about the same in 

 both cases. The difference between the two sets of seed- 

 lings, in the first experiment, was therefore probably due 

 to the unequal distribution throughout the soil in the pot 

 of the root-nodule-forming Bacteroids, more being present 

 on one side than on the other, the side in which they 

 were in greater abundance happening to be that in which 

 the normal seeds were planted. 



The effect upon vitality of excessive drying alone, is 

 partly shewn by the following experiments. Seeds were 

 placed in bottles, along with an open erect tube containing 

 a number of large clean pieces of the metal sodium. The 

 bottles were then stoppered and hermetically sealed, for 

 periods of 3 weeks and 5 weeks respectively. At the end 

 of the experiment they were opened and a known 

 number of each kind of seed planted. In the same pot 

 but separated from the former seeds by a partition an 

 equal number of the same seeds, which had been kept 

 alongside the bottles in loose paper bags exposed to the 

 air, were planted and the numbers given in the following 

 table are comparison percentages with these. The sodium 

 which the bottles contain exercises a double influence 

 upon the enclosed air. In the first place the oxygen 

 present combines with the sodium to form an oxide of 

 that metal, whilst any moisture which the air may contain 

 combines with the oxide or with the sodium directly to 

 form sodium hydrate, hydrogen being at the same time 

 given off. In a short time therefore the bottles contain 



