596 SCIENCE PROGRESS. 



inside and outside was mostly uniform and constantly as 

 low as 2>3° F- (presumably — ^2>°)' The excessive cold of 

 winter months, involving upwards of ioo° of frost, is also 

 not fatal to mature seeds. Grains of Triticum left at 

 Polaris Bay during Hall's expedition, which had lain en- 

 tirely exposed to the weather for four successive years, 

 germinated in Discovery Bay. Beans [Faba?) and peas 

 [Pis7im ?) that germinated had suffered the whole severity 

 of winter on deck with a minimal temperature of - 7 1 ° F. 



Kerner v. Marilaun^ cites that the mean tempera- 

 ture of January at Jakutsk and Werchojansk in Siberia is 

 - 42*8° C. to - 49° C, and that - 62*0° C. and - 63' 2° C, 

 the lowest temperature ever noted on the earth, have been 

 recorded there. Here also for months the shade-tempera- 

 ture in never above — 30° C. ; yet not only do seeds 

 germinate when the conditions become favourable, but 

 plants persist and live. 



Guppy (8) shows that enclosure in ice of an English 

 winter does not affect the ' vitality ' of seeds enclosed. 



Concerning resistance to high temperatures Just '^states 

 that seeds of Trifolmin pratense withstand temperatures up 

 to 120° C, if previously desiccated and kept so during the 

 experiment ; exposures were from half an hour to two 

 hours. Subjection to high temperatures always involves 

 slower and more imperfect germination than that to lower 

 ones. The more complete the desiccation is, he adds, the 

 less is the injury, but that most careful desiccation will not 

 prevent notable harm with temperatures over 100° C. 

 Later Just (10) experimented partly with carefully desic- 

 cated seeds. Dehydration w^as effected by exposure to 

 sulphuric acid for two days, then in a closed tube to calcium- 

 chloride for ten days at room-temperature ; subjection to 

 high temperatures took place in the tube. Hordeuui and 

 Avena were tested. If the tubes were placed in the ther- 

 mostat at once, the seeds of Hordeum were almost killed, 

 those of Avena considerably damaged ; if, however, they 

 were gradually taken to 100° C., thus effecting a more 



'^ FJlanzenleben, vol. i., 508. 



"^ Bot. Zfg., 1875, 52- Quoted in Just's paper (10) of bibliography. 



