82 STUDIES IN SEEDS AND FRUITS 



Professor Ewart gives the result of an experiment where, out 



of twenty-four seeds fifteen years old, five germinated. I only 



tested their keeping capacity in the case of two seeds collected 



by me ten and eleven years previously in Fiji, and found that 



both germinated readily and produced healthy plants. 



Negative Negative results in the germination of old impermeable 



beTexclusive- seeds should not be exclusively relied upon, since they may 



in testin the ar * se more f rom a failure in the conditions of the experiment 



longevity of than from a failure in the seed. For instance, it is not at all 



impermeable -11 ... ... . 



seeds. easy, one might almost say it is impossible, to exactly repro- 



duce the processes of nature in a soil-experiment. The initial 

 step, when we place in warm, moist conditions an impermeable 

 seed that has been lying dry for years in the air of a room is a 

 distinct departure from the natural process ; and, as Professor 

 Ewart shows in the case of an experiment on " fifty-year " old 

 seeds under what he describes as " optimal " conditions, there 

 may be no results. Yet if the seeds that still remain intact 

 and impermeable after such a soil-experiment are placed in a 

 germination chamber, after the impermeable cuticle has been 

 removed by sand-papering, about half on the average will ger- 

 minate. In such a case every seed having been made permeable 

 must either germinate or die. But we are not, I venture to 

 think, justified in presuming that the seeds which failed to 

 germinate in the second experiment had necessarily lost their 

 vitality. The inference we should be apt to draw from the first 

 soil-experiment that the seeds had lost their germinative powers 

 would be disproved, as Professor Ewart observes in recounting 

 the experiments, by the test in the germinating chamber ; and 

 it is equally possible that our second inference might be 

 erroneous if we assumed that the failures in the germinating 

 chamber are all to be attributed to the lost powers of the seed 

 and not to some failure in the conditions. 



Artificial methods, such as sand-papering, filing, scraping, 

 the use of an acid, etc., are generally necessary in experiments 

 to procure the germination of impermeable seeds, the seed 

 being rendered permeable by being deprived of its cuticle ; 



