August 19, 1893.] 



SCIENCE. 



215 



Nat. Mus. Washington, p. 138, 1896.) I 

 meant to correct my mistake when I read 

 my proof, but I neglected so to do. 



It, therefore, becomes necessary to give 

 the Georgia old field mouse a new name and 

 I propose for it Peromyseits subgriseits baliolu^^ 

 nom. nov. Type, No. 5925, Coll. of E. A. 

 and O. Bangs, described under above refer- 

 ence as Peromyseus mhgriseus arenarius, 



OuTBAM Bangs. 



BOTANICAL NOTES. 

 SEEDS AND VERY LOW TEMPEEATUEES. 



Two English investigators, H. T. Brown 

 and F. Escombe, recently made some in- 

 teresting experiments upon the ability of 

 seeds to endure very low temperatures. In 

 the Jodrell laboratory, of the Kew Gardens, 

 they enclosed seeds in thin glass tubes im- 

 mersed in a vacuum-jacketed flask contain- 

 ing about two liters of liquid air ; the latter 

 was replenished so as to submit the seeds, 

 for one hundred and ten hours, to a tempera- 

 ture of from —183° C. to -192° C. (-297 = 

 Fahr. to — 313° Fahr.). The seedsused were: 

 Sorcleum distichon, Avena sativa, Cucurbita 

 pepo, Cyclanthera explodens, Lotustetragonolobits, 

 Pimm elatlus, Trigonella foenum-graecimi, Im- 

 patiens balsamina, Helianthus annuus, Hera- 

 cleum villosum, Convolvidiis tricolor and Funlcia 

 sieboldiana. They had previously been air- 

 dried, and contained, when the experiment 

 was begun, from ten to twelve per cent, of 

 moisture. After their prolonged exposure 

 to the intense cold indicated above, they 

 were slowly thawed, the process requiring 

 about fifty hours. They were then tested as 

 to their germinative power, by comparison 

 with seeds from the same lots, which had not 

 been subjected to this low temperature, with 

 the result that ' their germinative power 

 showed no appreciable difference from that 

 of the controls, and the resulting plants, 

 which were in most cases grown to full ma- 



* Baliolus=dark-brown, swarthy. 



turity, were equally healthy in both cases.'' 

 This astonishing result can not fail to 

 attract much attention, not only of botan- 

 ists, but of gardeners and farmers as well. 

 That this was not due to unusual or acci- 

 dental conditions is shown by experiments 

 by other investigators, cited by Messrs 

 Brown and Escombe. Thus DeCandolle 

 and Pictet in 188-1 exposed seeds for four 

 days to a temperature of —100° C. (—148° 

 Fahr.) without destroying their vitality, 

 and in 1895 the former exposed seeds in the 

 ' snow box ' of a refrigerating machine for 

 a period of one hundred and eighteen days 

 to a temperature of from —37° C. to —53° 

 C. (—34.6° Fahr. to —63.4° Fahr.), a treat- 

 ment which most of the seed are said to have 

 ' resisted successfully.' 



"While these experiments are very inter- 

 esting as showing that mere lowering of 

 temperature may not necessarily destroy 

 the vitality of seeds, it is fair to the investi- 

 gators to say that this was not their princi- 

 pal object. They aimed to determine the 

 condition of the protoplasts of the resting 

 seed, whether (1) ' the essential elements of 

 the cell, during the period of inertness, are 

 still undergoing feeble but imperceptible 

 alteration, accompanied by gaseous inter- 

 change with the surrounding atmosphere,' 

 or (2) ' that all metabolism is completely 

 arrested in protoplasm when in the dormant 

 state, and that it then loses, for the time 

 being, all power of internal adjustment to 

 external conditions.' 



In other words, they asked the question : 

 ' Is the machinery of the dormant cell merely 

 slowed down to an indefinite extent, or is it 

 completely brought to rest for a time, to be once 

 more set going when external conditions are 

 favorable ? ' To this question they make 

 answer that ' we must regard the proto- 

 plasm in resting seeds as existing in an ab- 

 solutely inert state, devoid of any trace of 

 metabolic activity, and yet conserving the 

 potentiality of life.' 



