GERMINATION OF SEEDS. 589 



mained dormant for ten years, but the evidence adduced 

 is too inadequate to enable one to say with absolute 

 certainty that it was so. The seeds mii>"ht, for instance, 

 have been introduced on a spade, or in many other ways. 



The experiments that tend most strongly to prove 

 'longevity' in certain seeds are those of Girardin and of 

 Brown. The seeds tested had in each case been part of a 

 collection which there was every reason to suppose had 

 not been disturbed, and the age of which was known. But 

 there is no absolute certainty that the seeds had not been 

 interfered with, and this doubt weakens the evidence. 

 There is only one method for settling the question beyond 

 contradiction ; large quantities of selected seeds of many 

 species should be collected at some recognised institute 

 after careful previous treatment, and allowed to remain 

 quiescent in a suitable place, to which no one could get 

 access without being known to have done so. These seeds 

 should be periodically tested and the results recorded. The 

 research of Peter, although admirably conducted, only 

 supports strongly the idea of ' longevity ' of seeds. 



That this ' longevity ' is a function varying with the 

 species, and even individual seeds, admits of no doubt. 

 Burgerstein (i) found that deviations due to individual 

 differences in seeds of cereals amounted to from i to 16 per 

 cent. Moreover the degree of maturity at harvest-time 

 and the aqueous content at the time of preservation are 

 factors that influence considerably the ' vitality ' of seeds. 



Resistance to water. — The influence of oceanic agency 

 in distribution of certain plants has been long known ; this 

 is, stated in other words, that it has been long known that 

 certain seeds can withstand protracted immersion in salt 

 water. The old experiments of Darwin (6) on this point 

 are interesting. Seeds were placed in bottles with salt water 

 made according to Schweitzer's analysis. The trial was 

 fair, as algae and marine animals lived long in the water. 

 With Darwin's results are conjointly published some 

 of Berkeley's. The latter tied up seeds in bags and 

 immersed them in sea-water which was daily renewed ; 

 immersion lasted three weeks, but since the seeds were 



