590 SCIENCE PROGRESS. 



posted damp, and not at once unpacked, total immersion 

 was practically a month. Some of Darwin's bottles were 

 exposed to weekly temperatures of 35° to 57° F,, others to 

 daily ones of 46° to 56° F. Seeds were also immersed for 

 six weeks at 32° F., the temperature rising slowly during the 

 next six weeks to 44° F. But seeds thus tested did not 

 seem to withstand the injurious effect of salt water better 

 than those exposed to higher but variable temperatures. 

 The total number of species tested by the authors was 

 eighty-seven ; of these twenty-three did not ' survive ' im- 

 mersion of twenty-eight days. Capsicum was most re- 

 sistant, for thirty out of fifty-six seeds germinated after 

 immersion of 137 days, whereas of those of Apiuni grave- 

 olens only 6 per cent, germinated after like immersion. 

 Several seeds of Atriplex germinated after immersion of 

 100 days, but those of the dwarf kidney-bean and Hibiscus 

 Manihot were ' killed ' by immersion of eleven days. All 

 other species tested fell between these two extremes. It is 

 noteworthy that the majority of seeds tried were such as 

 might be expected to resist salt water least, not belonging 

 to littoral plants ; indeed, several were garden varieties. 



Hemsley^ cites experiments of Martins and Thuret on 

 this subject. The former tested ninety-eight species ; a 

 perforated box was employed with as many compartments 

 as kinds of seeds, being attached to a buoy. After ex- 

 posure of forty-five days the box was opened ; forty-one 

 kinds were rotten ; of the apparently sound remainder, 

 thirty-five germinated. Several of the latter were essen- 

 tially littoral. Fresh samples of the resistant thirty-five 

 kinds were immersed for ninety-three days ; only nine 

 withstood the trial. The conditions of these experiments 

 were better than those of Darwin's The experiments 

 of Thuret, in which immersion lasted thirteen months, 

 yielded similar results ; seeds of ten species (it is not stated 

 out of how many) germinated, several with more vigour 

 than the controls. 



Evidence adduced by Salter (7) tends to prove that 

 seeds can bear prolonged submersion in fresh and salt 

 ^ Challenger Report^ i- 3> appendix 277. 



